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Dai C, Huang C, Ye M, Liu J, Cheng H. Mild Catalyst- and Additive-Free Three-Component Synthesis of 3-Thioisoindolinones and Tricyclic γ-Lactams Accelerated by Microdroplet Chemistry. J Org Chem 2024; 89:14818-14830. [PMID: 39361508 DOI: 10.1021/acs.joc.4c01568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/05/2024]
Abstract
Isoindolinones, bearing both γ-lactam and aromatic rings, draw extensive interest in organic, pharmaceutical, and medicinal communities as they are important structural motifs in many natural products, bioactive compounds, and pharmaceuticals. As the main contributor to isoindolinone synthesis, metal catalysis is associated with many drawbacks including essential use of toxic/precious metals and excessive additives, high reaction temperatures, specially predesigned starting materials, and long reaction times (typically 8-30 h). In this study, we developed a catalyst- and additive-free, minute-scale, and high-yield microdroplet method for tricomponent isoindolinone synthesis at mild temperatures. By taking advantage of the astonishing reaction acceleration (1.9 × 102-9.4 × 103 acceleration factor range with a typical rate acceleration factor of 1.51 × 103 for the prototype reaction as the ratio of rate constants by microdroplet and bulk phase), 12 3-thioisoindolinones and two tricyclic γ-lactams were synthesized using various 2-acylbenzaldehydes, amines, and thiols with satisfactory yields ranging from 85% to 97% as well as a scale-up rate of 3.49 g h-1. Because of the advantages (no use of any catalysts or additives, mild temperature, rapid and satisfactory conversion, broad substrate scope, and gram scalability), the microdroplet method represents an attractive alternative to metal catalysis for laboratory synthesis of isoindolinones and their derivatives.
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Affiliation(s)
- Chengbiao Dai
- College of Material, Chemistry and Chemical Engineering, Key Laboratory of Organosilicon Chemistry and Material Technology, Ministry of Education, Hangzhou Normal University, 2318 Yuhangtang Road, Hangzhou 311121, China
| | - Chengkai Huang
- College of Material, Chemistry and Chemical Engineering, Key Laboratory of Organosilicon Chemistry and Material Technology, Ministry of Education, Hangzhou Normal University, 2318 Yuhangtang Road, Hangzhou 311121, China
| | - Meiying Ye
- College of Material, Chemistry and Chemical Engineering, Key Laboratory of Organosilicon Chemistry and Material Technology, Ministry of Education, Hangzhou Normal University, 2318 Yuhangtang Road, Hangzhou 311121, China
| | - Jinhua Liu
- College of Material, Chemistry and Chemical Engineering, Key Laboratory of Organosilicon Chemistry and Material Technology, Ministry of Education, Hangzhou Normal University, 2318 Yuhangtang Road, Hangzhou 311121, China
| | - Heyong Cheng
- College of Material, Chemistry and Chemical Engineering, Key Laboratory of Organosilicon Chemistry and Material Technology, Ministry of Education, Hangzhou Normal University, 2318 Yuhangtang Road, Hangzhou 311121, China
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2
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Hatvany JB, Olsen ELP, Gallagher ES. Characterizing Theta-Emitter Generation for Use in Microdroplet Reactions. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2024. [PMID: 39387805 DOI: 10.1021/jasms.4c00262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/15/2024]
Abstract
Theta emitters are useful for generating microdroplets for rapid-mixing reactions. Theta emitters are glass tips containing an internal septum that separates two channels. When used for mixing, the solutions from each channel are sprayed with mixing occurring during electrospray ionization (ESI) with reaction times on the order of microseconds to milliseconds. Theta emitters of increasing size cause the formation of ESI droplets of increasing size, which require longer times for desolvation and increase droplet lifetimes. Droplets with longer lifetimes provide more time for mixing and allow for increased reaction times prior to desolvation. Because theta emitters are typically produced in-house, there is a need to consistently pull tips with a variety of sizes. Herein, we characterize the effect of pull parameters on the generation of distinct-sized theta emitters using a P-1000 tip puller. Of the examined parameters, the velocity value had the largest impact on the channel diameter. This work also compares the effect of pulling parameters between single-channel and theta capillaries to examine how the internal septum in theta capillaries affects tip pulling. We demonstrate the utility of using theta emitters with different sizes for establishing distinct reaction times. Finally, we offer suggestions on producing theta emitters of various sizes while maintaining high repeatability. Through this work, we provide resources to establish a versatile and inexpensive rapid-mixing system for probing biologically relevant systems and performing rapid derivatizations.
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Affiliation(s)
- Jacob B Hatvany
- Department of Chemistry & Biochemistry, Baylor University, One Bear Place #97348, Waco, Texas 76798, United States
| | - Emma-Le P Olsen
- Department of Chemistry & Biochemistry, Baylor University, One Bear Place #97348, Waco, Texas 76798, United States
| | - Elyssia S Gallagher
- Department of Chemistry & Biochemistry, Baylor University, One Bear Place #97348, Waco, Texas 76798, United States
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3
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Bose S, Mofidfar M, Zare RN. Direct Conversion of N 2 and Air to Nitric Acid in Gas-Water Microbubbles. J Am Chem Soc 2024; 146:27964-27971. [PMID: 39315452 DOI: 10.1021/jacs.4c11899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/25/2024]
Abstract
We report a simple, direct, and green conversion of air/N2 to nitric acid by bubbling the gas through an aqueous solution containing 50 μM Fe2+ ions. Air stone, along with ultrasonication, was employed to generate gas microbubbles. H2O2 produced at the water-gas interface undergoes Fenton's reaction with Fe2+ ions to produce OH• that efficiently activates N2, yielding nitric acid as the final product. Nitrate (NO3-) formation occurs without the use of any external electric potential or radiation. The concentration of NO3- increased linearly with time over a period of 132 h. The average NO3- production rate is found to be 12.9 ± 0.05 μM h-1. We envision that this nitrogen fixation strategy that produces nitric acid in an eco-friendly way might open the possibility for the energy-efficient and green production of nitric acid.
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Affiliation(s)
- Sandeep Bose
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Mohammad Mofidfar
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Richard N Zare
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
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4
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Xue L, Chen W, Zheng P, Geng J, Zhang F, Li X, Zhang Z, Hu X. Catalyst-Free Oxidation of Styrene to Styrene Oxide Using Circulating Microdroplets in an Oxygen Atmosphere. J Am Chem Soc 2024; 146:26909-26915. [PMID: 39300790 DOI: 10.1021/jacs.4c08018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/22/2024]
Abstract
Water microdroplets possess unique interfacial properties that enable chemical reactions to occur spontaneously and increase the reaction rate by orders of magnitude. In this study, water containing styrene (SY) was cyclically sprayed into the air to form microdroplets with an average diameter of 6.7 μm. These microdroplets allowed SY to be oxidized into styrene oxide (SO) without catalysts. No oxidation products of SY were observed in the bulk solution under the same conditions, while in microdroplet reactions 4.2% conversion of SY with approximately 3.1 mM SO was detected. Compared with the traditional spraying microdroplet method, the oxidation product concentration was enhanced by 1000 times. Experiments proved that an aerobic environment boosts SY oxidation, leading to a proposed dual-path hydrogen peroxide (H2O2) oxidation mechanism at the droplet interface. This was confirmed by density functional theory calculations (DFT). Furthermore, in the presence of additional ultrasound, the SY oxidation process initiated by water droplets can be further enhanced, and 7.0% conversion of SY with approximately 5.2 mM SO was detected. The cyclic spraying method greatly enhanced the oxidation product concentration, showing the potential for large scale chemical production using microdroplets.
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Affiliation(s)
- Lian Xue
- Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, PR China
| | - Weida Chen
- Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, PR China
| | - Peng Zheng
- Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, PR China
| | - Jiao Geng
- Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, PR China
| | - Feng Zhang
- Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, PR China
| | - Xinyao Li
- Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, PR China
| | - Zhibing Zhang
- Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, PR China
| | - Xingbang Hu
- Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, PR China
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5
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Mehrgardi MA, Mofidfar M, Li J, Chamberlayne CF, Lynch SR, Zare RN. Catalyst-Free Transformation of Carbon Dioxide to Small Organic Compounds in Water Microdroplets Nebulized by Different Gases. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2406785. [PMID: 39129358 PMCID: PMC11481208 DOI: 10.1002/advs.202406785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2024] [Indexed: 08/13/2024]
Abstract
A straightforward nebulized spray system is designed to explore the hydrogenation of carbon dioxide (CO2) within water microdroplets surrounded by different gases such as carbon dioxide, nitrogen, oxygen, and compressed air. The collected droplets are analyzed using water-suppressed nuclear magnetic resonance (NMR). Formate anion (HCOO-), acetate anion (CH3COO-), ethylene glycol (HOCH2CH2OH), and methane (CH4) are detected when water is nebulized. This pattern persisted when the water is saturated with CO2, indicating that CO2 in the nebulizing gas triggers the formation of these small organics. In a pure CO2 atmosphere, the formate anion concentration is determined to be ≈70 µm, referenced to dimethyl sulfoxide, which has been introduced as an internal standard in the collected water droplets. This study highlights the power of water microdroplets to initiate unexpected chemistry for the transformation of CO2 to small organic compounds.
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Affiliation(s)
- Masoud A. Mehrgardi
- Department of ChemistryStanford UniversityStanfordCalifornia94305USA
- Department of ChemistryUniversity of IsfahanIsfahan81746Iran
| | - Mohammad Mofidfar
- Department of ChemistryStanford UniversityStanfordCalifornia94305USA
| | - Jia Li
- College of Chemical EngineeringShijiazhuang UniversityShijiazhuang050037China
| | | | - Stephen R. Lynch
- Department of ChemistryStanford UniversityStanfordCalifornia94305USA
| | - Richard N. Zare
- Department of ChemistryStanford UniversityStanfordCalifornia94305USA
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6
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Zhang J, Tian S, Zhu C, Han L, Zhang X. The synthesis of polydopamine nano- and microspheres in microdroplets. Chem Commun (Camb) 2024; 60:11068-11071. [PMID: 39206971 DOI: 10.1039/d4cc03017f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
Here we developed a microdroplet-based strategy for the rapid synthesis of uniform polydopamine nano- and microspheres. Polydopamine spheres with controllable sizes were generated within hundreds of microseconds by simply spraying water solutions of dopamine into microdroplets. Mass spectrometry revealed that dopamine was primarily oxidized into aminochrome, acting as the major building block for polydopamine. We anticipate that microdroplet chemistry will be rich in opportunities for the synthesis of functional nano- and micromaterials.
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Affiliation(s)
- Jianze Zhang
- College of Chemistry, Frontiers Science Center for New Organic Matter, State Key Laboratory of Advanced Chemical Power Sources, Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Tianjin Key Laboratory of Biosensing and Molecular Recognition, Renewable Energy Conversion and Storage Center (ReCAST), Nankai University, Tianjin, 300071, China.
| | - Shufang Tian
- School of Energy Science and Technology, Henan University, Zhengzhou, 450046, China.
| | - Chenghui Zhu
- College of Chemistry, Frontiers Science Center for New Organic Matter, State Key Laboratory of Advanced Chemical Power Sources, Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Tianjin Key Laboratory of Biosensing and Molecular Recognition, Renewable Energy Conversion and Storage Center (ReCAST), Nankai University, Tianjin, 300071, China.
| | - Lifeng Han
- State Key Laboratory of Component-Based Chinese Medicine, Haihe Laboratory of Modern Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 301617, China.
| | - Xinxing Zhang
- College of Chemistry, Frontiers Science Center for New Organic Matter, State Key Laboratory of Advanced Chemical Power Sources, Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Tianjin Key Laboratory of Biosensing and Molecular Recognition, Renewable Energy Conversion and Storage Center (ReCAST), Nankai University, Tianjin, 300071, China.
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7
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Sui X, Yu XY. An evaluation of static ToF-SIMS analysis of environmental organics. Heliyon 2024; 10:e37913. [PMID: 39315229 PMCID: PMC11417316 DOI: 10.1016/j.heliyon.2024.e37913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Revised: 09/10/2024] [Accepted: 09/12/2024] [Indexed: 09/25/2024] Open
Abstract
Time-of-flight secondary ion mass spectrometry (ToF-SIMS) has been extensively used in surface analysis due to its high mass resolution, sensitivity, and mass spectral imaging capabilities. Static ToF-SIMS has mainly been used for solid material analysis; however, its application in environmental organics is limited. During SIMS spectral analysis, relative mass accuracy and measurement repeatability are key factors for obtaining reliable speciation and acquiring chemical insights of the specimens. Herein, we provide an evaluation of four environmentally relevant organic systems, including glyoxal, pyruvic acid, oil-in-water emulsion, and carbon dioxide (CO2) capture solvent (i.e., N-2-ethoxyethyl-3-morpholinopropan-1-amine, EMMPA), to show the spectral measurement repeatability when using static ToF-SIMS. First, sample preparation is essential in acquiring accurate and reproducible results in ToF-SIMS analysis. The mass spectral results show that characteristic peaks observed can be distinguished with reasonable confidence by comparing the observed mass to charge ratios (m/z) to theoretical ones. The statistical analysis of peak areas indicates that the peak area and/or peak height measurement ratios are satisfactory among replicates. Compared with previous studies, the bismuth cluster primary ion beam, namely Bi3 +, has less fragmentation than Bi+. Therefore, Bi3 + is deemed more suitable for organic analysis using static SIMS. Our results show that ToF-SIMS offers a viable approach to study environmental organics including but not limited to aqueous aerosols, wastewater emulsions, and CO2 capture solvents. It is expected that future studies will expand organic speciation with high fidelity due to the continued advancement of SIMS as a sensitive analysis technique.
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Affiliation(s)
- Xiao Sui
- College of Geography and Environment, Shandong Normal University, Jinan, 250358, China
| | - Xiao-Ying Yu
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37830-6136, United States
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8
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Abdul-Khalek N, Wimmer R, Overgaard MT, Gregersen Echers S. Decoding the impact of neighboring amino acids on ESI-MS intensity output through deep learning. J Proteomics 2024; 309:105322. [PMID: 39341565 DOI: 10.1016/j.jprot.2024.105322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Revised: 07/15/2024] [Accepted: 09/24/2024] [Indexed: 10/01/2024]
Abstract
Peptide-level quantification using mass spectrometry (MS) is no trivial task as the physicochemical properties affect both response and detectability. The specific amino acid (AA) sequence affects these properties, however the connection between sequence and intensity output remains poorly understood. In this work, we explore combinations of amino acid pairs (i.e., dimer motifs) to determine a potential relationship between the local amino acid environment and MS1 intensity. For this purpose, a deep learning (DL) model, consisting of an encoder-decoder with an attention mechanism, was built. The attention mechanism allowed to identify the most relevant motifs. Specific patterns were consistently observed where a bulky/aromatic and hydrophobic AA followed by a cationic AA as well as consecutive bulky/aromatic and hydrophobic AAs were found important for the prediction of the MS1 intensity. Correlating attention weights to mean MS1 intensities revealed that some important motifs, particularly containing Trp, His, and Cys, were linked with low responding peptides whereas motifs containing Lys and most bulky hydrophobic AAs were often associated with high responding peptides. Moreover, Asn-Gly was associated with low response. The model predicts MS1 response with a mean average percentage error of ∼11 % and a Pearson correlation coefficient of ∼0.64. While dimer representation of peptide sequences did not improve predictive capacity compared to single AA representation in earlier work, this work adds valuable insight for a better understanding of peptide response in MS analysis. SIGNIFICANCE: Mass spectrometry is not inherently quantitative, and the response of a compound relies not only on its concentration but also on the molecular composition. For mass spectrometry-based analysis of peptides, such as in bottom-up proteomics, this directly implies that the response cannot be used directly to quantify individual peptides. Moreover, the dependency of the response on the amino acid sequence of individual peptides remains poorly understood. Using a deep learning model based on a recurrent neural network with an attention mechanism, we here investigate how the presence of dimer motifs within a peptide affects the MS1 response through the analysis of intended equimolar peptide pools comprising almost 200,000 unique peptides in total. Not only do we identify certain dimer classes and specific dimers that substantially affect the MS1 response, but the model is also able to predict peptide intensity with low error rates within the independent test subset. The findings not only improve our understanding of the link between sequence and response for peptides but also highlight the potential of utilizing deep learning for developing methods allowing for absolute, label-free peptide quantification.
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Affiliation(s)
- Naim Abdul-Khalek
- Department of Chemistry and Bioscience, Aalborg University, Fredrik Bajers Vej 7H, Aalborg 9220, Denmark
| | - Reinhard Wimmer
- Department of Chemistry and Bioscience, Aalborg University, Fredrik Bajers Vej 7H, Aalborg 9220, Denmark
| | - Michael Toft Overgaard
- Department of Chemistry and Bioscience, Aalborg University, Fredrik Bajers Vej 7H, Aalborg 9220, Denmark
| | - Simon Gregersen Echers
- Department of Chemistry and Bioscience, Aalborg University, Fredrik Bajers Vej 7H, Aalborg 9220, Denmark..
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Chao S, Valsecchi C, Sun J, Shao H, Li X, Tang C, Fan M. Highly Sensitive Surface-Enhanced Raman Scattering Detection of Hydroxyl Radicals in Water Microdroplets Using Phthalhydrazide/Ag Nanoparticles Nanosensor. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:16497-16506. [PMID: 39114886 DOI: 10.1021/acs.est.4c03081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/18/2024]
Abstract
The spontaneous generation of hydrogen peroxide (H2O2) within atmospheric microdroplets, such as raindrops and aerosols, plays a crucial role in various environmental processes including pollutant degradation and oxidative stress. However, quantifying hydroxyl radicals (•OH), essential for H2O2 formation, remains challenging due to their short lifespan and low concentration. This study addresses this gap by presenting a highly sensitive and selective surface-enhanced Raman scattering (SERS) nanosensor specifically designed for quantifying •OH within water microdroplets. Utilizing a phthalhydrazide (Phth) probe, the SERS technique enables rapid, interference-free detection of •OH at nanomolar concentrations. It achieves a linear detection range from 2 nM to 2 μM and a limit of detection as low as 0.34 nM. Importantly, the SERS sensor demonstrates robustness and accuracy within water microdroplets, paving the way for comprehensive mechanistic studies of H2O2 generation in the atmosphere. This innovative approach not only offers a powerful tool for environmental research but also holds potential for advancing our understanding of atmospheric H2O2 formation and its impact on air quality and pollutant degradation.
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Affiliation(s)
- Shengmao Chao
- School of Environmental Science and Engineering, Southwest Jiaotong University, Chengdu 610031, China
- Chengdu Development Center of Science and Technology, China Academy of Engineering Physics, Chengdu 610200, China
| | - Chiara Valsecchi
- Federal University of Pampa, Campus Alegrete, 97542-160 Alegrete, Rio Grande do Sul, Brazil
| | - Ji Sun
- Department of Student Affairs, Henan University of Technology, 450001 Zhengzhou, China
| | - Hong Shao
- Chengdu Development Center of Science and Technology, China Academy of Engineering Physics, Chengdu 610200, China
| | - Xinxia Li
- Chengdu Development Center of Science and Technology, China Academy of Engineering Physics, Chengdu 610200, China
| | - Changyu Tang
- Chengdu Development Center of Science and Technology, China Academy of Engineering Physics, Chengdu 610200, China
| | - Meikun Fan
- School of Environmental Science and Engineering, Southwest Jiaotong University, Chengdu 610031, China
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10
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Li M, Yang S, Rathi M, Kumar S, Dutcher CS, Grassian VH. Enhanced condensation kinetics in aqueous microdroplets driven by coupled surface reactions and gas-phase partitioning. Chem Sci 2024; 15:13429-13441. [PMID: 39183898 PMCID: PMC11339779 DOI: 10.1039/d4sc03014a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2024] [Accepted: 07/17/2024] [Indexed: 08/27/2024] Open
Abstract
Although aqueous microdroplets have been shown to exhibit enhanced chemical reactivity compared to bulk solutions, mechanisms for these enhancements are not completely understood. Here we combine experimental measurements and kinetic modeling to show the strong coupling of interfacial reactions and gas/droplet partitioning in the condensation reaction of pyruvic acid (PA) to yield zymonic acid (ZA) in acidic aqueous microdroplets. Experimental analysis of single microdroplets reveals the substantial influence of evaporation of PA and partitioning of water on the size-, relative humidity (RH)- and temperature-dependent sigmoidal reaction kinetics for the condensation reaction. A newly developed diffusion-reaction-partitioning model is used to simulate the complex kinetics observed in the microdroplets. The model can quantitatively predict the size and compositional changes as the reaction proceeds under different environmental conditions, and provides insights into how microdroplet reactivity is controlled by coupled interfacial reactions and the gas-phase partitioning of PA and water. Importantly, the kinetic model best fits the data when an autocatalytic step is included in the mechanism, i.e. a reaction step where the product, ZA, catalyzes the interfacial condensation reaction. Overall, the dynamic nature of aqueous microdroplet chemistry and the coupling of interfacial chemistry with gas-phase partitioning are demonstrated. Furthermore, autocatalysis of small organic molecules at the air-water interface for aqueous microdroplets, shown here for the first time, has implications for several fields including prebiotic chemistry, atmospheric chemistry and chemical synthesis.
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Affiliation(s)
- Meng Li
- Department of Chemistry and Biochemistry, University of California San Diego La Jolla CA 92093 USA
| | - Shu Yang
- Department of Mechanical Engineering, University of Minnesota Minneapolis MN 55455 USA
| | - Meenal Rathi
- Department of Chemical Engineering and Materials Science, University of Minnesota Minneapolis MN 55455 USA
| | - Satish Kumar
- Department of Chemical Engineering and Materials Science, University of Minnesota Minneapolis MN 55455 USA
| | - Cari S Dutcher
- Department of Mechanical Engineering, University of Minnesota Minneapolis MN 55455 USA
- Department of Chemical Engineering and Materials Science, University of Minnesota Minneapolis MN 55455 USA
| | - Vicki H Grassian
- Department of Chemistry and Biochemistry, University of California San Diego La Jolla CA 92093 USA
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11
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Brown JB, Qian Y, Wang H, Zhang T, Huang-Fu ZC, Rao Y. Quantitative Signal Analysis of Sum-Frequency Scattering Experiments from Aerosol Surfaces. Anal Chem 2024; 96:13607-13615. [PMID: 39126390 DOI: 10.1021/acs.analchem.4c02397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/12/2024]
Abstract
Droplet interfaces are instrumental in processes of biology, engineering, production, and environmental systems. The chemical and physical properties of heterogeneous interfaces are known to be different from those of their underlying bulk phases, and different again when considering the curved surface of submicron aerosol droplets. The recently developed technique of vibrational sum-frequency scattering (VSFS) spectroscopy from airborne particles has emerged as an interface-specific method for the in situ analysis of this unique system. While the technique has shown promise in debut works, a quantitative analysis of the VSFS system has not yet been performed. Here we provide a comprehensive analysis of a VSFS spectrometer with reference to the well-documented planar analog. We decompose the VSFS signal into coherent and incoherent as well as resonant and nonresonant components as a function of incident pulse delay time. We then quantify and compare resonant and nonresonant VSFS and VSFG experimental data using the same laser and detection systems. Using the air/water interface as a guide, we show that the resonant and nonresonant contributions to the SF responses are comparable for the two systems by extracting second-order susceptibilities and hyperpolarizabilities, and using them to estimate single-particle susceptibilities. A quantitative analysis of the signal detection systems for the scattering and planar geometries is made, and conversion efficiencies for VSFG, VSFS, and other nonlinear scattering experiments are compared. Lastly, the possibility of a low-repetition (1 kHz) VSFS spectrometer is considered, determining that it may be possible with modern laser technology but is inevitably less efficient than a high-repetition (100 kHz) system. Though this multistep analysis we obtain a better understanding of the components of the VSFS signal from aerosol particles, further validate the feasibility of the experiments, and provide insight to those wishing to conduct similar experiments and how they may be improved.
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Affiliation(s)
- Jesse B Brown
- Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84322, United States
| | - Yuqin Qian
- Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84322, United States
| | - Hui Wang
- Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84322, United States
| | - Tong Zhang
- Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84322, United States
| | - Zhi-Chao Huang-Fu
- Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84322, United States
| | - Yi Rao
- Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84322, United States
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12
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Sano M, Kamei K, Yatsuhashi T, Sakota K. Localization and Orientation of Dye Molecules at the Surface of a Levitated Microdroplet in Air Revealed by Whispering Gallery Mode Resonances. J Phys Chem Lett 2024; 15:8133-8141. [PMID: 39087939 DOI: 10.1021/acs.jpclett.4c01819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/02/2024]
Abstract
Microdroplets offer unique environments that accelerate chemical reactions; however, the mechanisms behind these processes remain debated. The localization and orientation of solute molecules near the droplet surface have been proposed as factors for this acceleration. Since significant reaction acceleration has been observed for electrospray- and sonic-spray-generated aerosol droplets, the analysis of microdroplets in air has become essential. Here, we utilized whispering gallery mode (WGM) resonances to investigate the localization and orientation of dissolved rhodamine B (RhB) in a levitated microdroplet (∼3 μm in diameter) in air. Fluorescence enhancement upon resonance with the WGMs revealed the localization and orientation of RhB near the droplet surface. Numerical modeling using Mie theory quantified the RhB orientation at 68° to the surface normal, with a small fraction randomly oriented inside the droplet. Additionally, low RhB concentrations increased surface localization. These results support the significance of surface reactions in the acceleration of microdroplet reactions.
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Affiliation(s)
- Motoya Sano
- Division of Molecular Material Science, Graduate School of Science, Osaka City University, 3-3-138, Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
| | - Kota Kamei
- Division of Molecular Material Science, Graduate School of Science, Osaka City University, 3-3-138, Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
| | - Tomoyuki Yatsuhashi
- Department of Chemistry, Graduate School of Science, Osaka Metropolitan University, 3-3-138, Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
| | - Kenji Sakota
- Department of Chemistry, Graduate School of Science, Osaka Metropolitan University, 3-3-138, Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
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13
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Qiu L, Li X, Holden DT, Cooks RG. Reaction acceleration at the surface of a levitated droplet by vapor dosing from a partner droplet. Chem Sci 2024; 15:12277-12283. [PMID: 39118618 PMCID: PMC11304536 DOI: 10.1039/d4sc03528c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2024] [Accepted: 06/30/2024] [Indexed: 08/10/2024] Open
Abstract
Chemical reactions in micrometer-sized droplets can be accelerated by up to six orders of magnitude. However, this acceleration factor (ratio of rate constants relative to bulk) drops to less than 10 for millimeter-sized droplets due to the reduction in surface/volume ratio. To enhance the acceleration in millimeter-sized droplets, we use a new synthesis platform that directly doses reagent vapor onto the reaction droplet surface from a second levitated droplet. Using Katritzky transamination as a model reaction, we made quantitative measurements on size-controlled vapor-dosed droplets, revealing a 31-fold increase in reaction rate constants when examining the entire droplet contents. This enhancement is attributed to a greater reaction rate constant in the droplet surface region (estimated as 105 times greater than that for the bulk). The capability for substantial reaction acceleration in large droplets highlights the potential for rapid synthesis of important chemicals at useful scales. For example, we successfully prepared 23 pyridinium salts within minutes. This efficiency positions droplets as an exceptional platform for rapid, in situ catalyst synthesis. This is illustrated by the preparation of pyridinium salts as photocatalysts and their subsequent use in mediation of amine oxidation both within the same droplet.
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Affiliation(s)
- Lingqi Qiu
- Department of Chemistry, Purdue University 560 Oval Drive West Lafayette Indiana 47907 USA
| | - Xilai Li
- Department of Chemistry, Purdue University 560 Oval Drive West Lafayette Indiana 47907 USA
| | - Dylan T Holden
- Department of Chemistry, Purdue University 560 Oval Drive West Lafayette Indiana 47907 USA
| | - R Graham Cooks
- Department of Chemistry, Purdue University 560 Oval Drive West Lafayette Indiana 47907 USA
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14
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Martins-Costa MTC, Ruiz-López MF. The Structure of Carbon Dioxide at the Air-Water Interface and its Chemical Implications. Chemistry 2024; 30:e202400825. [PMID: 38838064 DOI: 10.1002/chem.202400825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 05/14/2024] [Accepted: 05/31/2024] [Indexed: 06/07/2024]
Abstract
The efficient reduction of CO2 into valuable products is a challenging task in an international context marked by the climate change crisis and the need to move away from fossil fuels. Recently, the use of water microdroplets has emerged as an interesting reaction media where many redox processes which do not occur in conventional solutions take place spontaneously. Indeed, several experimental studies in microdroplets have already been devoted to study the reduction of CO2 with promising results. The increased reactivity in microdroplets is thought to be linked to unique electrostatic solvation effects at the air-water interface. In the present work, we report a theoretical investigation on this issue for CO2 using first-principles molecular dynamics simulations. We show that CO2 is stabilized at the interface, where it can accumulate, and that compared to bulk water solution, its electron capture ability is larger. Our results suggest that reduction of CO2 might be easier in interface-rich systems such as water microdroplets, which is in line with early experimental data and indicate directions for future laboratory studies. The effect of other relevant factors which could play a role in CO2 reduction potential is discussed.
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Affiliation(s)
- Marilia T C Martins-Costa
- Laboratoire de Physique et Chimie Théoriques, UMR CNRS 7019, University of Lorraine, CNRS, BP 70239, 54506, Vandoeuvre-lès-Nancy, France
| | - Manuel F Ruiz-López
- Laboratoire de Physique et Chimie Théoriques, UMR CNRS 7019, University of Lorraine, CNRS, BP 70239, 54506, Vandoeuvre-lès-Nancy, France
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15
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Guo S, Ji Y, Liao G, Wang J, Shen ZH, Qi X, Liebscher C, Cheng N, Ren L, Ge B. Tailoring Heterostructure Growth on Liquid Metal Nanodroplets through Interface Engineering. J Am Chem Soc 2024; 146:19800-19808. [PMID: 38976349 DOI: 10.1021/jacs.4c02521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
Liquid metal (LM) nanodroplets possess intriguing surface properties, thus offering promising potential in chemical synthesis, catalysis, and biomedicine. However, the reaction kinetics and product growth at the surface of LM nanodroplets are significantly influenced by the interface involved, which has not been thoroughly explored and understood. Here, we propose an interface engineering strategy, taking a spontaneous galvanic reaction between Ga0 and AuCl4- ions as a representative example, to successfully modulate the growth of heterostructures on the surface of Ga-based LM nanodroplets by establishing a dielectric interface with a controllable thickness between LM and reactive surroundings. Combining high-resolution electron energy-loss spectroscopy (EELS) analysis and theoretical simulation, it was found that the induced charge distribution at the interface dominates the spatiotemporal distribution of the reaction sites. Employing tungsten oxide (WOx) with varying thicknesses as the demonstrated dielectric interface of LM, Ga@WOx@Au with distinct core-shell-satellite or dimer-like heterostructures has been achieved and exhibited different photoresponsive capabilities for photodetection. Understanding the kinetics of product growth and the regulatory strategy of the dielectric interface provides an experimental approach to controlling the structure and properties of products in LM nanodroplet-involved chemical processes.
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Affiliation(s)
- Siqi Guo
- Information Materials and Intelligent Sensing Laboratory of Anhui Province, Leibniz International Joint Research Center of Materials Sciences of Anhui Province, Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, P. R. China
| | - Yuan Ji
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, International School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070, P. R. China
| | | | - Jian Wang
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, International School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070, P. R. China
| | - Zhong-Hui Shen
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, International School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070, P. R. China
| | - Xiang Qi
- Xiangtan University, Xiangtan 411105, P. R. China
| | | | - Ningyan Cheng
- Information Materials and Intelligent Sensing Laboratory of Anhui Province, Leibniz International Joint Research Center of Materials Sciences of Anhui Province, Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, P. R. China
- Max-Planck-Institut für Eisenforschung GmbH, 40237 Düsseldorf, Germany
| | - Long Ren
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, International School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070, P. R. China
| | - Binghui Ge
- Information Materials and Intelligent Sensing Laboratory of Anhui Province, Leibniz International Joint Research Center of Materials Sciences of Anhui Province, Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, P. R. China
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16
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Zhang X, Huang K, Fu Y, Zhang N, Kong X, Cheng Y, Zheng M, Cheng Y, Zhu T, Fu B, Feng S, Chen H. Demethylation C-C coupling reaction facilitated by the repulsive Coulomb force between two cations. Nat Commun 2024; 15:5881. [PMID: 38997250 PMCID: PMC11245495 DOI: 10.1038/s41467-024-49946-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2023] [Accepted: 06/26/2024] [Indexed: 07/14/2024] Open
Abstract
Carbon chain elongation (CCE) is normally carried out using either chemical catalysts or bioenzymes. Herein we demonstrate a catalyst-free approach to promote demethylation C-C coupling reactions for advanced CCE constructed with functional groups under ambient conditions. Accelerated by the electric field, two organic cations containing a methyl group (e.g., ketones, acids, and aldehydes) approach each other with such proximity that the energy of the repulsive Coulomb interaction between these two cations exceeds the bond energy of the methyl group. This results in the elimination of a methyl cation and the coupling of the residual carbonyl carbon groups. As confirmed by high-resolution mass spectrometry and isotope-labeling experiments, the C-C coupling reactions (yields up to 76.5%) were commonly observed in the gas phase or liquid phase, for which the mechanism was further studied using molecular dynamics simulations and stationary-point calculations, revealing deep insights and perspectives of chemistry.
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Affiliation(s)
- Xiaoping Zhang
- Jiangxi Key Laboratory for Mass Spectrometry and Instrumentation, East China University of Technology, Nanchang, 330013, P. R. China
| | - Keke Huang
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Jilin University, Changchun, 130012, P. R. China
| | - Yanlin Fu
- State Key Laboratory of Molecular Reaction Dynamics, Center for Theoretical and Computational Chemistry, Dalian Institution of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, P. R. China
| | - Ni Zhang
- School of Pharmacy, Jiangxi University of Chinese Medicine, Nanchang, 330004, P. R. China
| | - Xianglei Kong
- State Key Laboratory of Elemento-organic Chemistry, College of Chemistry, Nankai University, Tianjin, 300071, P. R. China
| | - Yuanyuan Cheng
- Jiangxi Key Laboratory for Mass Spectrometry and Instrumentation, East China University of Technology, Nanchang, 330013, P. R. China
| | - Mingyu Zheng
- Jiangxi Key Laboratory for Mass Spectrometry and Instrumentation, East China University of Technology, Nanchang, 330013, P. R. China
| | - Yihao Cheng
- Jiangxi Key Laboratory for Mass Spectrometry and Instrumentation, East China University of Technology, Nanchang, 330013, P. R. China
| | - Tenggao Zhu
- School of Pharmacy, Jiangxi University of Chinese Medicine, Nanchang, 330004, P. R. China
| | - Bina Fu
- State Key Laboratory of Molecular Reaction Dynamics, Center for Theoretical and Computational Chemistry, Dalian Institution of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, P. R. China.
- Hefei National Laboratory, Hefei, 230088, China.
| | - Shouhua Feng
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Jilin University, Changchun, 130012, P. R. China.
| | - Huanwen Chen
- Jiangxi Key Laboratory for Mass Spectrometry and Instrumentation, East China University of Technology, Nanchang, 330013, P. R. China.
- School of Pharmacy, Jiangxi University of Chinese Medicine, Nanchang, 330004, P. R. China.
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17
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Bain RM, Stutzman JR, Pannuto J, Kane M. Characterization of 2-Butanone Peroxide Oligomeric Profiles and Their Associated Gas-Phase and Solution-Phase Rearrangement Products by Electrospray Ionization Mass Spectrometry for Forensic Applications. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2024; 35:1470-1479. [PMID: 38669013 DOI: 10.1021/jasms.4c00065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2024]
Abstract
2-Butanone peroxide (also known as methyl ethyl ketone peroxide, MEKP) has applications as a cross-linker in the chemical industry and is also encountered as a homemade primary high explosive; therefore, it is of interest to both process chemists and forensic examiners. Specifically for forensic applications, we demonstrate that when traditional synthetic procedures, available to any hobbyist, are utilized to generate MEKP, oligomeric peroxide units (n ≤ 12), along with several other oligomeric byproduct distributions, are readily observed by liquid chromatography-mass spectrometry (LC-MS). These oligomeric byproducts correspond to the formation of methyl/ethyl ketone end group(s) at the oligomer end group (i.e., loss of ethanol(s) and/or methanol(s) from the oligomer termini). Based on the interpretation of the MS and MS/MS behavior along with the characterization of newly generated terminal alkyl ketone products, we propose that these byproducts are consistent with a Hock-like rearrangement of the primary MEKP distribution in the acidified reaction medium. Following a procedure for homemade preparation, triplicate lots were synthesized. Unique oligomeric and byproduct distributions provided discriminatory power between the synthetic lots. Furthermore, the distributions of MEKP oligomers and the various byproducts in the initiated MEKP match the intensity distributions observed in the intact material with remarkable accuracy. This observation suggests that the postinitiation residue of MEKP could be associated or dissociated from a separately collected intact material obtained during an investigation by examining these oligomeric and byproduct profiles.
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Affiliation(s)
- Ryan M Bain
- The Bureau of Alcohol, Tobacco, Firearms and Explosives, Ammendale, Maryland 20705, United States
| | - John R Stutzman
- The Dow Chemical Company, Midland, Michigan 48667, United States
| | - Julie Pannuto
- The Bureau of Alcohol, Tobacco, Firearms and Explosives, Ammendale, Maryland 20705, United States
| | - Meghan Kane
- The Bureau of Alcohol, Tobacco, Firearms and Explosives, Ammendale, Maryland 20705, United States
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18
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Bain A, Lalemi L, Croll Dawes N, Miles REH, Prophet AM, Wilson KR, Bzdek BR. Surfactant Partitioning Dynamics in Freshly Generated Aerosol Droplets. J Am Chem Soc 2024; 146:16028-16038. [PMID: 38822805 PMCID: PMC11177314 DOI: 10.1021/jacs.4c03041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 05/21/2024] [Accepted: 05/22/2024] [Indexed: 06/03/2024]
Abstract
Aerosol droplets are unique microcompartments with relevance to areas as diverse as materials and chemical synthesis, atmospheric chemistry, and cloud formation. Observations of highly accelerated and unusual chemistry taking place in such droplets have challenged our understanding of chemical kinetics in these microscopic systems. Due to their large surface-area-to-volume ratios, interfacial processes can play a dominant role in governing chemical reactivity and other processes in droplets. Quantitative knowledge about droplet surface properties is required to explain reaction mechanisms and product yields. However, our understanding of the compositions and properties of these dynamic, microscopic interfaces is poor compared to our understanding of bulk processes. Here, we measure the dynamic surface tensions of 14-25 μm radius (11-65 pL) droplets containing a strong surfactant (either sodium dodecyl sulfate or octyl-β-D-thioglucopyranoside) using a stroboscopic imaging approach, enabling observation of the dynamics of surfactant partitioning to the droplet-air interface on time scales of 10s to 100s of microseconds after droplet generation. The experimental results are interpreted with a state-of-the-art kinetic model accounting for the unique high surface-area-to-volume ratio inherent to aerosol droplets, providing insights into both the surfactant diffusion and adsorption kinetics as well as the time-dependence of the interfacial surfactant concentration. This study demonstrates that microscopic droplet interfaces can take up to many milliseconds to reach equilibrium. Such time scales should be considered when attempting to explain observations of accelerated chemistry in microcompartments.
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Affiliation(s)
- Alison Bain
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, U.K.
- Department
of Chemistry, Oregon State University, Corvallis, Oregon 97331, United States
| | - Lara Lalemi
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, U.K.
| | - Nathan Croll Dawes
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, U.K.
| | - Rachael E. H. Miles
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, U.K.
| | - Alexander M. Prophet
- Department
of Chemistry, University of California, Berkeley, California 94720, United States
- Chemical
Sciences Division, Lawrence Berkeley National
Laboratory, Berkeley, California 94720, United States
| | - Kevin R. Wilson
- Chemical
Sciences Division, Lawrence Berkeley National
Laboratory, Berkeley, California 94720, United States
| | - Bryan R. Bzdek
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, U.K.
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19
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Judd KD, Parsons SW, Eremin DB, Fokin VV, Dawlaty JM. Visualizing partial solvation at the air-water interface. Chem Sci 2024; 15:8346-8354. [PMID: 38846382 PMCID: PMC11151832 DOI: 10.1039/d4sc01311e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2024] [Accepted: 04/08/2024] [Indexed: 06/09/2024] Open
Abstract
Despite significant research, the mechanistic nuances of unusual reactivity at the air-water interface, especially in microdroplets, remain elusive. The likely contributors include electric fields and partial solvation at the interface. To reveal these intricacies, we measure the frequency shift of a well-defined azide vibrational probe at the air-water interface, while independently controlling the surface charge density by introducing surfactants. First, we establish the response of the probe in the bulk and demonstrate that it is sensitive to both electrostatics and hydrogen bonding. From interfacial spectroscopy we infer that the azide is neither fully hydrated nor in a completely aprotic dielectric environment; instead, it experiences an intermediate environment. In the presence of hydrogen bond-accepting sulphate surfactants, competition arises for interfacial water with the azide. However, the dominant influence stems from the electrostatic effect of their negative heads, resulting in a significant blue-shift. Conversely, for the positive ammonium surfactants, our data indicate a balanced interplay between electrostatics and hydrogen bonding, leading to a minimal shift in the probe. Our results demonstrate partial solvation at the interface and highlights that both hydrogen bonding and electrostatics may assist or oppose each other in polarizing a reactant, intermediate, or product at the interface, which is important for understanding and tuning interfacial reactivity.
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Affiliation(s)
- Kenneth D Judd
- Department of Chemistry, The University of Southern California Los Angeles CA 90089 USA
| | - Sean W Parsons
- Department of Chemistry, The University of Southern California Los Angeles CA 90089 USA
| | - Dmitry B Eremin
- Department of Chemistry, The University of Southern California Los Angeles CA 90089 USA
| | - Valery V Fokin
- Department of Chemistry, The University of Southern California Los Angeles CA 90089 USA
| | - Jahan M Dawlaty
- Department of Chemistry, The University of Southern California Los Angeles CA 90089 USA
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20
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Wilson KR, Prophet AM. Chemical Kinetics in Microdroplets. Annu Rev Phys Chem 2024; 75:185-208. [PMID: 38382571 DOI: 10.1146/annurev-physchem-052623-120718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2024]
Abstract
Micrometer-sized compartments play significant roles in driving heterogeneous transformations within atmospheric and biochemical systems as well as providing vehicles for drug delivery and novel reaction environments for the synthesis of industrial chemicals. Many reports now indicate that reaction kinetics are accelerated under microconfinement, for example, in sprays, thin films, droplets, aerosols, and emulsions. These observations are dramatic, posing a challenge to our understanding of chemical reaction mechanisms with potentially significant practical consequences for predicting the complex chemistry in natural systems. Here we introduce the idea of kinetic confinement, which is intended to provide a conceptual backdrop for understanding when and why microdroplet reaction kinetics differ from their macroscale analogs.
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Affiliation(s)
- Kevin R Wilson
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA;
| | - Alexander M Prophet
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA;
- Department of Chemistry, University of California, Berkeley, California, USA;
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21
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Cooks RG, Holden DT. Breaking down microdroplet chemistry. Science 2024; 384:958-959. [PMID: 38815043 DOI: 10.1126/science.adp7627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2024]
Abstract
Charged microdroplets accelerate mineral disintegration.
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Affiliation(s)
- R Graham Cooks
- Department of Chemistry, Purdue University, West Lafayette, IN, USA
| | - Dylan T Holden
- Department of Chemistry, Purdue University, West Lafayette, IN, USA
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22
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Fan J, Liang L, Zhou X, Ouyang Z. Accelerating protein aggregation and amyloid fibrillation for rapid inhibitor screening. Chem Sci 2024; 15:6853-6859. [PMID: 38725489 PMCID: PMC11077537 DOI: 10.1039/d4sc00437j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Accepted: 04/04/2024] [Indexed: 05/12/2024] Open
Abstract
The accumulation and deposition of amyloid fibrils, also known as amyloidosis, in tissues and organs of patients has been found to be linked to numerous devastating neurodegenerative diseases. The aggregation of proteins to form amyloid fibrils, however, is a slow pathogenic process, and is a major issue for the evaluation of the effectiveness of inhibitors in new drug discovery and screening. Here, we used microdroplet reaction technology to accelerate the amyloid fibrillation process, monitored the process to shed light on the fundamental mechanism of amyloid self-assembly, and demonstrated the value of the technology in the rapid screening of potential inhibitor drugs. Proteins in microdroplets accelerated to form fibrils in milliseconds, enabling an entire cycle of inhibitor screening for Aβ40 within 3 minutes. The technology would be of broad interest to drug discovery and therapeutic design to develop treatments for diseases associated with protein aggregation and fibrillation.
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Affiliation(s)
- Jingjin Fan
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University Beijing 100084 China
| | - Liwen Liang
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University Beijing 100084 China
| | - Xiaoyu Zhou
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University Beijing 100084 China
| | - Zheng Ouyang
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University Beijing 100084 China
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23
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Voci S, Vannoy KJ, Dick JE. Femtoliter oil droplets act as CO 2 micropumps for uninterrupted electrochemiluminescence at the water|oil interface. J Colloid Interface Sci 2024; 661:853-860. [PMID: 38330657 PMCID: PMC11307245 DOI: 10.1016/j.jcis.2024.01.100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 01/04/2024] [Accepted: 01/14/2024] [Indexed: 02/10/2024]
Abstract
Interfacial effects are well-known to significantly alter chemical reactivity, especially in confined environments, where the surface to volume ratio increases. Here, we observed an inhomogeneity in the electrogenerated chemiluminescence (ECL) intensity decrease over time in a multiphasic system composed of femtoliter water droplets entrapping femtoliter volumes of the 1,2-dichloroethane (DCE) continuous phase. In usual electrochemiluminescence (ECL) reactions involving an ECL chromophore and oxalate ([C2O4]2-), the build-up of CO2 diminishes the ECL signal with time because of bubble formation. We hypothesised that relative solubilities of chemical species in these environments play a dramatic role in interfacial reactivity. Water droplets, loaded with the ECL luminophore [Ru(bpy)3]2+ and the coreactant [C2O4]2- were allowed to stochastically collide and adsorb at the surface of a glassy carbon macroelectrode. When water droplets coalesce on the surface, they leave behind femtoliter droplets of the DCE phase (inclusions). We report the surprising finding that the addition of multiple interfaces, due to the presence of continuous phase's femtoliter inclusions, allows sustained ECL over time after successive potential applications at the triple-phase boundary between water droplet|electrode|DCE inclusion. When femtoliter droplets of DCE form on the electrode surface, bright rings of ECL are observed during the simultaneous oxidation of [Ru(bpy)3]2+ and [C2O4]2-. Control experiments and finite element modelling allowed us to propose that these rings arise because CO2 that is generated near the 1,2-dichloroethane droplet partitions in due to relative solubility of CO2 in 1,2-dichloroethane and builds up and/or is expelled at the top of the droplet. The small droplets of the DCE phase act as micropumps, pumping away carbon dioxide from the interface. These results highlight the unexpected point that confined microenvironments and their geometry can tune chemical reactions of industrial importance and fundamental interest.
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Affiliation(s)
- Silvia Voci
- Department of Chemistry, Purdue University, West Lafayette, IN 47907, USA
| | - Kathryn J Vannoy
- Department of Chemistry, Purdue University, West Lafayette, IN 47907, USA
| | - Jeffrey E Dick
- Department of Chemistry, Purdue University, West Lafayette, IN 47907, USA; Elmore Family School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN 47907, USA.
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24
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Chen G, Chu F, Zhang S, Li W, Zhou S, Wei W, Chen W, Wang X, Yue L, Feng H, Cui Y, Pan Y. Ortho C-H Bond Activations in an Atmospheric Microwave Plasma Ion Source. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2024; 35:951-959. [PMID: 38597607 DOI: 10.1021/jasms.4c00011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/11/2024]
Abstract
C-H bond ortho-substitution reaction has always been a significant and challenging topic in organic chemistry. We proposed a synthesis method based on microwave plasma torches. High-resolution mass spectrometry was used to monitor rapid reaction products. 2-Alkylbenzimidazole can be formed through the reaction of phenylnitrenium ion and nitriles on a millisecond scale. This reaction can achieve the one-step formation of benzimidazoles from benzene ring single-substituted compounds without the addition of external oxidants or catalysts. A similar C-H bond activation reaction can be accomplished with ketones. Meanwhile, the microwave plasma reactor was modified, and the resulting 2-methylbenzimidazole was successfully collected, indicating the device has good application potential in organic reactions such as C-H bond activation reaction.
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Affiliation(s)
- Guanru Chen
- Department of Chemistry, Zhejiang University, Hangzhou 310027 Zhejiang, P. R. China
| | - Fengjian Chu
- Dr. Li Dak Sum & Yip Yio Chin Center for Stem Cell and Regenerative Medicine, College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou 310027, Zhejiang, P. R. China
| | - Shuheng Zhang
- Department of Chemistry, Zhejiang University, Hangzhou 310027 Zhejiang, P. R. China
| | - Wangyu Li
- Department of Chemistry, Zhejiang University, Hangzhou 310027 Zhejiang, P. R. China
| | - Shiwen Zhou
- Department of Chemistry, Zhejiang University, Hangzhou 310027 Zhejiang, P. R. China
| | - Wei Wei
- Department of Chemistry, Zhejiang University, Hangzhou 310027 Zhejiang, P. R. China
| | - Weiwei Chen
- Department of Chemistry, Zhejiang University, Hangzhou 310027 Zhejiang, P. R. China
| | - Xiaozhi Wang
- Dr. Li Dak Sum & Yip Yio Chin Center for Stem Cell and Regenerative Medicine, College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou 310027, Zhejiang, P. R. China
| | - Lei Yue
- College of Biology, Hunan University, Changsha 410082, Hunan, P. R. China
| | - Hongru Feng
- Department of Chemistry, Zhejiang University, Hangzhou 310027 Zhejiang, P. R. China
| | - Yanli Cui
- Department of Chemistry, Zhejiang University, Hangzhou 310027 Zhejiang, P. R. China
| | - Yuanjiang Pan
- Department of Chemistry, Zhejiang University, Hangzhou 310027 Zhejiang, P. R. China
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25
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Heindel JP, LaCour RA, Head-Gordon T. The role of charge in microdroplet redox chemistry. Nat Commun 2024; 15:3670. [PMID: 38693110 DOI: 10.1038/s41467-024-47879-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 04/12/2024] [Indexed: 05/03/2024] Open
Abstract
In charged water microdroplets, which occur in nature or in the lab upon ultrasonication or in electrospray processes, the thermodynamics for reactive chemistry can be dramatically altered relative to the bulk phase. Here, we provide a theoretical basis for the observation of accelerated chemistry by simulating water droplets of increasing charge imbalance to create redox agents such as hydroxyl and hydrogen radicals and solvated electrons. We compute the hydration enthalpy of OH- and H+ that controls the electron transfer process, and the corresponding changes in vertical ionization energy and vertical electron affinity of the ions, to create OH• and H• reactive species. We find that at ~ 20 - 50% of the Rayleigh limit of droplet charge the hydration enthalpy of both OH- and H+ have decreased by >50 kcal/mol such that electron transfer becomes thermodynamically favorable, in correspondence with the more favorable vertical electron affinity of H+ and the lowered vertical ionization energy of OH-. We provide scaling arguments that show that the nanoscale calculations and conclusions extend to the experimental microdroplet length scale. The relevance of the droplet charge for chemical reactivity is illustrated for the formation of H2O2, and has clear implications for other redox reactions observed to occur with enhanced rates in microdroplets.
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Affiliation(s)
- Joseph P Heindel
- Kenneth S. Pitzer Theory Center and Department of Chemistry, Berkeley, CA, USA
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - R Allen LaCour
- Kenneth S. Pitzer Theory Center and Department of Chemistry, Berkeley, CA, USA
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Teresa Head-Gordon
- Kenneth S. Pitzer Theory Center and Department of Chemistry, Berkeley, CA, USA.
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
- Departments of Bioengineering and Chemical and Biomolecular Engineering University of CAlifornia, Berkeley, CA, USA.
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26
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Qiu L, Cooks RG. Spontaneous Oxidation in Aqueous Microdroplets: Water Radical Cation as Primary Oxidizing Agent. Angew Chem Int Ed Engl 2024; 63:e202400118. [PMID: 38302696 DOI: 10.1002/anie.202400118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 01/28/2024] [Accepted: 01/29/2024] [Indexed: 02/03/2024]
Abstract
Exploration of the unique chemical properties of interfaces can unlock new understanding. A striking example is the finding of accelerated reactions, particularly spontaneous oxidation reactions, that occur without assistance of catalysts or external oxidants at the air interface of both aqueous and organic solutions (provided they contain some water). This finding opened a new area of interfacial chemistry but also caused heated debate regarding the primary chemical species responsible for the observed oxidation. An overview of the literature covering oxidation in microdroplets with air interfaces is provided, together with a critical examination of previous findings and hypotheses. The water radical cation/radical anion pair, formed spontaneously and responsible for the electric field at or near the droplet/air interface, is suggested to constitute the primary redox species. Mechanisms of accelerated microdroplet reactions are critically discussed and it is shown that hydroxyl radical/hydrogen peroxide formation in microdroplets does not require that these species be the primary oxidant. Instead, we suggest that hydroxyl radical and hydrogen peroxide are the products of water radical cation decay in water. The importance of microdroplet chemistry in the prebiotic environment is sketched briefly and the role of partial solvation in reaction acceleration is noted.
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Affiliation(s)
- Lingqi Qiu
- Department of Chemistry, Purdue University, West Lafayette, IN 47907, U.S
| | - R Graham Cooks
- Department of Chemistry, Purdue University, West Lafayette, IN 47907, U.S
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27
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Chen H, Wang R, Chiba T, Foreman K, Bowen K, Zhang X. Designer "Quasi-Benzyne": The Spontaneous Reduction of Ortho-Diiodotetrafluorobenzene on Water Microdroplets. J Am Chem Soc 2024; 146:10979-10983. [PMID: 38586980 DOI: 10.1021/jacs.4c02819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
It has been widely shown that water microdroplets have a plethora of unique properties that are highly distinct from those of bulk water, among which an especially intriguing one is the strong reducing power as a result of the electrons spontaneously generated at the air-water interface. In this study, we take advantage of the reducing power of water microdroplets to reduce ortho-diiodotetrafluorobenzene (o-C6F4I2) into a C6F4I2•- radical anion. Photoelectron spectroscopy and density functional theory computations reveal that the excess electron in C6F4I2•- occupies the I-C1-C2-I linkage, which elongates the C-I bonds but surprisingly shortens the C1-C2 bond, making the bond order higher than a double bond, similar to the benzyne molecule, so we named it "quasi-benzyne". The C6F4I2•- anion was further successfully utilized in a Diels-Alder reaction, a typical reaction for benzyne. This study provides a good example of strategically utilizing the spontaneous properties of water microdroplets and generating an especially exotic anion, and we anticipate that microdroplet chemistry can be an avenue rich in opportunities for new catalyst-free organic reactions.
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Affiliation(s)
- Huan Chen
- College of Chemistry, Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Renewable Energy Conversion and Storage Centre, Tianjin Key Laboratory of Biosensing and Molecular Recognition, Frontiers Science Centre for New Organic Matter, Nankai University, Tianjin300071, China
- Haihe Laboratory of Sustainable Chemical Transformations, Tianjin300192, China
| | - Ruijing Wang
- College of Chemistry, Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Renewable Energy Conversion and Storage Centre, Tianjin Key Laboratory of Biosensing and Molecular Recognition, Frontiers Science Centre for New Organic Matter, Nankai University, Tianjin300071, China
- Haihe Laboratory of Sustainable Chemical Transformations, Tianjin300192, China
| | - Tatsuya Chiba
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Kathryn Foreman
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Kit Bowen
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Xinxing Zhang
- College of Chemistry, Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Renewable Energy Conversion and Storage Centre, Tianjin Key Laboratory of Biosensing and Molecular Recognition, Frontiers Science Centre for New Organic Matter, Nankai University, Tianjin300071, China
- Haihe Laboratory of Sustainable Chemical Transformations, Tianjin300192, China
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28
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Song Z, Zhu C, Gong K, Wang R, Zhang J, Zhao S, Li Z, Zhang X, Xie J. Deciphering the Microdroplet Acceleration Factors of Aza-Michael Addition Reactions. J Am Chem Soc 2024; 146:10963-10972. [PMID: 38567839 DOI: 10.1021/jacs.4c02312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/18/2024]
Abstract
Microdroplet chemistry is emerging as a great tool for accelerating reactions by several orders of magnitude. Several unique properties such as extreme pHs, interfacial electric fields (IEFs), and partial solvation have been reported to be responsible for the acceleration; however, which factor plays the key role remains elusive. Here, we performed quantum chemical calculations to explore the underlying mechanisms of an aza-Michael addition reaction between methylamine and acrylamide. We showed that the acceleration in methanol microdroplets results from the cumulative effects of several factors. The acidic surface of the microdroplet plays a dominating role, leading to a decrease of ∼9 kcal/mol in the activation barrier. We speculated that the dissociation of both methanol and trace water contributes to the surface acidity. An IEF of 0.1 V/Å can further decrease the barrier by ∼2 kcal/mol. Partial solvation has a negligible effect on lowering the activation barrier in microdroplets but can increase the collision frequency between reactants. With acidity revealed to be the major accelerating factor for methanol droplets, reactions on water microdroplets should have even higher rates because water is more acidic. Both theoretically and experimentally, we confirmed that water microdroplets significantly accelerate the aza-Michael reaction, achieving an acceleration factor that exceeds 107. This work elucidates the multifactorial influences on the microdroplet acceleration mechanism, and with such detailed mechanistic investigations, we anticipate that microdroplet chemistry will be an avenue rich in opportunities in the realm of green synthesis.
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Affiliation(s)
- Zhexuan Song
- Key Laboratory of Cluster Science of Ministry of Education, Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Chenghui Zhu
- College of Chemistry, Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Renewable Energy Conversion and Storage Centre, Tianjin Key Laboratory of Biosensing and Molecular Recognition, Frontiers Science Centre for New Organic Matter, Nankai University, Tianjin 300071, China
| | - Ke Gong
- Key Laboratory of Cluster Science of Ministry of Education, Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Ruijing Wang
- College of Chemistry, Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Renewable Energy Conversion and Storage Centre, Tianjin Key Laboratory of Biosensing and Molecular Recognition, Frontiers Science Centre for New Organic Matter, Nankai University, Tianjin 300071, China
| | - Jianze Zhang
- College of Chemistry, Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Renewable Energy Conversion and Storage Centre, Tianjin Key Laboratory of Biosensing and Molecular Recognition, Frontiers Science Centre for New Organic Matter, Nankai University, Tianjin 300071, China
| | - Supin Zhao
- Key Laboratory of Cluster Science of Ministry of Education, Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Zesheng Li
- Key Laboratory of Cluster Science of Ministry of Education, Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Xinxing Zhang
- College of Chemistry, Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Renewable Energy Conversion and Storage Centre, Tianjin Key Laboratory of Biosensing and Molecular Recognition, Frontiers Science Centre for New Organic Matter, Nankai University, Tianjin 300071, China
| | - Jing Xie
- Key Laboratory of Cluster Science of Ministry of Education, Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China
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29
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Song X, Yan H, Zhang Y, Zhou W, Li S, Zhang J, Ciampi S, Zhang L. Hydroxylation of the indium tin oxide electrode promoted by surface bubbles. Chem Commun (Camb) 2024; 60:4186-4189. [PMID: 38530669 DOI: 10.1039/d4cc00307a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/28/2024]
Abstract
Adherent bubbles at electrodes are generally treated as reaction penalties. Herein, in situ hydroxylation of indium tin oxide surfaces can be easily achieved by applying a constant potential of +1.0 V in the presence of bubbles. Its successful hydroxylation is further demonstrated by preparing a ferrocene-terminated film, which is confirmed by cyclic voltammetry and X-ray photoelectron spectroscopy.
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Affiliation(s)
- Xiaoxue Song
- Institute of Quantum and Sustainable Technology (IQST), School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang City, 212013, Jiangsu Province, China.
| | - Hui Yan
- Institute of Quantum and Sustainable Technology (IQST), School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang City, 212013, Jiangsu Province, China.
| | - Yuqiao Zhang
- Institute of Quantum and Sustainable Technology (IQST), School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang City, 212013, Jiangsu Province, China.
| | - Weiqiang Zhou
- Institute of Quantum and Sustainable Technology (IQST), School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang City, 212013, Jiangsu Province, China.
| | - Shun Li
- Institute of Quantum and Sustainable Technology (IQST), School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang City, 212013, Jiangsu Province, China.
| | - Jianming Zhang
- Institute of Quantum and Sustainable Technology (IQST), School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang City, 212013, Jiangsu Province, China.
| | - Simone Ciampi
- School of Molecular and Life Sciences, Curtin University, Bentley, Western Australia 6102, Australia.
| | - Long Zhang
- Institute of Quantum and Sustainable Technology (IQST), School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang City, 212013, Jiangsu Province, China.
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30
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Bouza M, Foest D, Brandt S, García-Reyes JF, Franzke J. Enhanced Compound Analysis Using Reactive Paper Spray Mass Spectrometry: Leveraging Schiff Base Reaction for Amino Acid Detection. Anal Chem 2024; 96:5289-5297. [PMID: 38507224 PMCID: PMC10993198 DOI: 10.1021/acs.analchem.4c00215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 02/29/2024] [Accepted: 03/04/2024] [Indexed: 03/22/2024]
Abstract
Paper spray mass spectrometry (PS-MS) has evolved into a promising tool for monitoring reactions in thin films and microdroplets, known as reactive PS, alongside its established role in ambient and direct ionization. This study addresses the need for rapid, cost-effective methods to improve analyte identification in biofluids by leveraging reactive PS-MS in clinical chemistry environments. The technique has proven effective in derivatizing target analytes, altering hydrophobicity to enhance elution and ionization efficiency, and refining detection through thin-film reactions on paper, significantly expediting reaction rates by using amino acids (AAs) as model analytes. These molecules are prone to interacting with substrates like paper, impeding elution and detection. Additionally, highly abundant species in biofluids, such as lipids, often suppress AA ionization. This study employs the Schiff base (SB) reaction utilizing aromatic aldehydes for AA derivatization to optimize reaction conditions time, temperature, and catalyst presence and dramatically increasing the conversion ratio (CR) of formed SB. For instance, using leucine as a model AA, the CR surged from 57% at room temperature to 89% at 70 °C, with added pyridine during and after 7.5 min, displaying a 43% CR compared to the bulk reaction. Evaluation of various aromatic aldehydes as derivatization agents highlighted the importance of specific oxygen substituents for achieving higher conversion rates. Furthermore, diverse derivatization agents unveiled unique fragmentation pathways, aiding in-depth annotation of the target analyte. Successfully applied to quantify AAs in human and rat plasma, this reactive PS-MS approach showcases promising potential in efficiently detecting conventionally challenging compounds in PS-MS analysis.
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Affiliation(s)
- Marcos Bouza
- Analytical
Chemistry Research Group, Department of Physical and Analytical Chemistry, University of Jaén, Campus Las Lagunillas, Jaén 23071, Spain
| | - Daniel Foest
- ISAS—Leibniz
Institut für Analytische Wissenschaften, Bunsen-Kirchhoff-Str. 11, Dortmund 44139, Germany
| | - Sebastian Brandt
- ISAS—Leibniz
Institut für Analytische Wissenschaften, Bunsen-Kirchhoff-Str. 11, Dortmund 44139, Germany
| | - Juan F. García-Reyes
- Analytical
Chemistry Research Group, Department of Physical and Analytical Chemistry, University of Jaén, Campus Las Lagunillas, Jaén 23071, Spain
| | - Joachim Franzke
- ISAS—Leibniz
Institut für Analytische Wissenschaften, Bunsen-Kirchhoff-Str. 11, Dortmund 44139, Germany
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31
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Zhang R, Zhang Z, Chen X, Jiang J, Hua L, Jia X, Bao R, Wang F. Pyrogenic Carbon Degradation by Galvanic Coupling with Sprayed Seawater Microdroplets. J Am Chem Soc 2024; 146:8528-8535. [PMID: 38497738 DOI: 10.1021/jacs.4c00290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
Surface waves are known for their mechanical role in coastal processes that influence the weather and climate. However, their chemical impact, particularly on the transformation of pyrogenic carbon, is poorly understood. Pyrogenic carbon is generally assumed to show negligible postformational alteration of its stable carbon isotope composition. Here we present an electrochemical interaction of pyrogenic carbon with the sprayed seawater microdroplets resulting from wave breaking, driven by the galvanic coupling between the microdroplet water-carbon interfaces and the microdroplet water-vapor interfaces. This enables refractory pyrogenic carbon to rapidly degrade via the oxygenation and mineralization reaction, which makes it ∼2.6‰ enriched in 13C, far exceeding the generally assumed postformation alteration values (<0.5‰) of pyrogenic carbon. The unique chemical dynamics of seawater microdroplets provide new insights into the discrepancy in carbon isotope signatures between riverine and marine black carbon, emphasizing the potential of coastal oceans for carbon sequestration in the global carbon cycle.
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Affiliation(s)
- Ruolan Zhang
- Henan Institute of Advanced Technology, Zhengzhou University, Zhengzhou 450000, P. R. China
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, P. R. China
| | - Zhenyuan Zhang
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Xuke Chen
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Jichun Jiang
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, P. R. China
| | - Lei Hua
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, P. R. China
| | - Xiuquan Jia
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, P. R. China
| | - Rui Bao
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, Key Lab of Marine Chemistry Theory and Technology, Ocean University of China, Qingdao 266100, P. R. China
| | - Feng Wang
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
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32
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Angelaki M, Carreira Mendes Da Silva Y, Perrier S, George C. Quantification and Mechanistic Investigation of the Spontaneous H 2O 2 Generation at the Interfaces of Salt-Containing Aqueous Droplets. J Am Chem Soc 2024; 146:8327-8334. [PMID: 38488457 PMCID: PMC10979748 DOI: 10.1021/jacs.3c14040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/28/2024]
Abstract
There is now much evidence that OH radicals and H2O2 are spontaneously generated at the air-water interface of atmospheric aerosols. Here, we investigated the effect of halide anions (Cl-, Br-, I-), which are abundant in marine aerosols, on this H2O2 production. Droplets were generated via nebulization of water solutions containing Na2SO4, NaCl, NaBr, and NaI containing solutions, and H2O2 was monitored as a function of the salt concentration under atmospheric relevant conditions. The interfacial OH radical formation was also investigated by adding terephthalic acid (TA) to our salt solutions, and the product of its reaction with OH, hydroxy terephthalic acid (TAOH), was monitored. Finally, a mechanistic investigation was performed to examine the reactions participating in H2O2 production, and their respective contributions were quantified. Our results showed that only Br- contributes to the interfacial H2O2 formation, promoting the production by acting as an electron donor, while Na2SO4 and NaCl stabilized the droplets by only reducing their evaporation. TAOH was observed in the collected droplets and, for the first time, directly in the particle phase by means of online fluorescence spectroscopy, confirming the interfacial OH production. A mechanistic study suggests that H2O2 is formed by both OH and HO2 self-recombination, as well as HO2 reaction with H atoms. This work is expected to enhance our understanding of interfacial processes and assess their impact on climate, air quality, and health.
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Affiliation(s)
- Maria Angelaki
- Université Claude Bernard Lyon 1, CNRS, IRCELYON, UMR 5256, F-69626, Villeurbanne, France
| | | | - Sébastien Perrier
- Université Claude Bernard Lyon 1, CNRS, IRCELYON, UMR 5256, F-69626, Villeurbanne, France
| | - Christian George
- Université Claude Bernard Lyon 1, CNRS, IRCELYON, UMR 5256, F-69626, Villeurbanne, France
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33
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de la Puente M, Gomez A, Laage D. Neural Network-Based Sum-Frequency Generation Spectra of Pure and Acidified Water Interfaces with Air. J Phys Chem Lett 2024; 15:3096-3102. [PMID: 38470065 DOI: 10.1021/acs.jpclett.4c00113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/13/2024]
Abstract
The affinity of hydronium ions (H3O+) for the air-water interface is a crucial question in environmental chemistry. While sum-frequency generation (SFG) spectroscopy has been instrumental in indicating the preference of H3O+ for the interface, key questions persist regarding the molecular origin of the SFG spectral changes in acidified water. Here we combine nanosecond long neural network (NN) reactive simulations of pure and acidified water slabs with NN predictions of molecular dipoles and polarizabilities to calculate SFG spectra of long reactive trajectories including proton transfer events. Our simulations show that H3O+ ions cause two distinct changes in phase-resolved SFG spectra: first, a low-frequency tail due to the vibrations of H3O+ and its first hydration shell, analogous to the bulk proton continuum, and second, an enhanced hydrogen-bonded band due to the ion-induced static field polarizing molecules in deeper layers. Our calculations confirm that changes in the SFG spectra of acidic solutions are caused by hydronium ions preferentially residing at the interface.
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Affiliation(s)
- Miguel de la Puente
- PASTEUR, Department of Chemistry, École Normale Supérieur, PSL University, Sorbonne Université, CNRS, 75005 Paris, France
| | - Axel Gomez
- PASTEUR, Department of Chemistry, École Normale Supérieur, PSL University, Sorbonne Université, CNRS, 75005 Paris, France
| | - Damien Laage
- PASTEUR, Department of Chemistry, École Normale Supérieur, PSL University, Sorbonne Université, CNRS, 75005 Paris, France
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34
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Yu J, Liu J, Li C, Huang J, Zhu Y, You H. Recent advances and applications in high-throughput continuous flow. Chem Commun (Camb) 2024; 60:3217-3225. [PMID: 38436212 DOI: 10.1039/d3cc06180a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/05/2024]
Abstract
High-throughput continuous flow technology has emerged as a revolutionary approach in chemical synthesis, offering accelerated experimentation and improved efficiency. With the aid of process analytical technology and automation, this system not only enables rapid optimisation of reaction conditions at the millimole to the picomole scale, but also facilitates automated scale-up synthesis. It can even achieve the self-planning and self-synthesis of small drug molecules with artificial intelligence incorporated in the system. The versatility of the system is highlighted by its compatibility with both electrochemistry and photochemistry, and its significant applications in organic synthesis and drug discovery. This highlight summarises its recent developments and applications, emphasising its significant impact on advancing research across multiple disciplines.
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Affiliation(s)
- Jiaping Yu
- School of Science, Harbin Institute of Technology (Shenzhen), Shenzhen, 518055, China.
| | - Jiaying Liu
- Institute of Advanced Technology of Heilongjiang Academy of Sciences, Harbin, 150000, China
| | - Chaoyi Li
- School of Science, Harbin Institute of Technology (Shenzhen), Shenzhen, 518055, China.
| | - Junrong Huang
- School of Science, Harbin Institute of Technology (Shenzhen), Shenzhen, 518055, China.
| | - Yuxiang Zhu
- School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen, 518107, China.
| | - Hengzhi You
- School of Science, Harbin Institute of Technology (Shenzhen), Shenzhen, 518055, China.
- Green Pharmaceutical Engineering Research Centre, Harbin Institute of Technology (Shenzhen), Shenzhen, 518055, China
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35
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Wang W, Liu Y, Wang T, Ge Q, Li K, Liu J, You W, Wang L, Xie L, Fu H, Chen J, Zhang L. Significantly Accelerated Photosensitized Formation of Atmospheric Sulfate at the Air-Water Interface of Microdroplets. J Am Chem Soc 2024; 146:6580-6590. [PMID: 38427385 DOI: 10.1021/jacs.3c11892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2024]
Abstract
The multiphase oxidation of sulfur dioxide (SO2) to form sulfate is a complex and important process in the atmosphere. While the conventional photosensitized reaction mainly explored in the bulk medium is reported to be one of the drivers to trigger atmospheric sulfate production, how this scheme functionalizes at the air-water interface (AWI) of aerosol remains an open question. Herein, employing an advanced size-controllable microdroplet-printing device, surface-enhanced Raman scattering (SERS) analysis, nanosecond transient adsorption spectrometer, and molecular level theoretical calculations, we revealed the previously overlooked interfacial role in photosensitized oxidation of SO2 in humic-like substance (HULIS) aerosol, where a 3-4 orders of magnitude increase in sulfate formation rate was speculated in cloud and aerosol relevant-sized particles relative to the conventional bulk-phase medium. The rapid formation of a battery of reactive oxygen species (ROS) comes from the accelerated electron transfer process at the AWI, where the excited triplet state of HULIS (3HULIS*) of the incomplete solvent cage can readily capture electrons from HSO3- in a way that is more efficient than that in the bulk medium fully blocked by water molecules. This phenomenon could be explained by the significantly reduced desolvation energy barrier required for reagents residing in the AWI region with an open solvent shell.
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Affiliation(s)
- Wei Wang
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary, IRDR International Center of Excellence on Risk Interconnectivity and Governance on Weather, Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, Peoples' Republic of China
| | - Yangyang Liu
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary, IRDR International Center of Excellence on Risk Interconnectivity and Governance on Weather, Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, Peoples' Republic of China
| | - Tao Wang
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary, IRDR International Center of Excellence on Risk Interconnectivity and Governance on Weather, Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, Peoples' Republic of China
| | - Qiuyue Ge
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary, IRDR International Center of Excellence on Risk Interconnectivity and Governance on Weather, Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, Peoples' Republic of China
| | - Kejian Li
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary, IRDR International Center of Excellence on Risk Interconnectivity and Governance on Weather, Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, Peoples' Republic of China
| | - Juan Liu
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary, IRDR International Center of Excellence on Risk Interconnectivity and Governance on Weather, Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, Peoples' Republic of China
| | - Wenbo You
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary, IRDR International Center of Excellence on Risk Interconnectivity and Governance on Weather, Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, Peoples' Republic of China
| | - Longqian Wang
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary, IRDR International Center of Excellence on Risk Interconnectivity and Governance on Weather, Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, Peoples' Republic of China
| | - Lifang Xie
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary, IRDR International Center of Excellence on Risk Interconnectivity and Governance on Weather, Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, Peoples' Republic of China
| | - Hongbo Fu
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary, IRDR International Center of Excellence on Risk Interconnectivity and Governance on Weather, Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, Peoples' Republic of China
| | - Jianmin Chen
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary, IRDR International Center of Excellence on Risk Interconnectivity and Governance on Weather, Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, Peoples' Republic of China
| | - Liwu Zhang
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary, IRDR International Center of Excellence on Risk Interconnectivity and Governance on Weather, Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, Peoples' Republic of China
- Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, Peoples' Republic of China
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36
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Galembeck F, Santos LP, Burgo TAL, Galembeck A. The emerging chemistry of self-electrified water interfaces. Chem Soc Rev 2024; 53:2578-2602. [PMID: 38305696 DOI: 10.1039/d3cs00763d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2024]
Abstract
Water is known for dissipating electrostatic charges, but it is also a universal agent of matter electrification, creating charged domains in any material contacting or containing it. This new role of water was discovered during the current century. It is proven in a fast-growing number of publications reporting direct experimental measurements of excess charge and electric potential. It is indirectly verified by its success in explaining surprising phenomena in chemical synthesis, electric power generation, metastability, and phase transition kinetics. Additionally, electrification by water is opening the way for developing green technologies that are fully compatible with the environment and have great potential to contribute to sustainability. Electrification by water shows that polyphasic matter is a charge mosaic, converging with the Maxwell-Wagner-Sillars effect, which was discovered one century ago but is still often ignored. Electrified sites in a real system are niches showing various local electrochemical potentials for the charged species. Thus, the electrified mosaics display variable chemical reactivity and mass transfer patterns. Water contributes to interfacial electrification from its singular structural, electric, mixing, adsorption, and absorption properties. A long list of previously unexpected consequences of interfacial electrification includes: "on-water" reactions of chemicals dispersed in water that defy current chemical wisdom; reactions in electrified water microdroplets that do not occur in bulk water, transforming the droplets in microreactors; and lowered surface tension of water, modifying wetting, spreading, adhesion, cohesion, and other properties of matter. Asymmetric capacitors charged by moisture and water are now promising alternative equipment for simultaneously producing electric power and green hydrogen, requiring only ambient thermal energy. Changing surface tension by interfacial electrification also modifies phase-change kinetics, eliminating metastability that is the root of catastrophic electric discharges and destructive explosions. It also changes crystal habits, producing needles and dendrites that shorten battery life. These recent findings derive from a single factor, water's ability to electrify matter, touching on the most relevant aspects of chemistry. They create tremendous scientific opportunities to understand the matter better, and a new chemistry based on electrified interfaces is now emerging.
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Affiliation(s)
- Fernando Galembeck
- Department of Physical Chemistry, University of Campinas, Institute of Chemistry, 13083-872, Campinas, Brazil.
- Galembetech Consultores e Tecnologia, 13080-661, Campinas, Brazil
| | - Leandra P Santos
- Galembetech Consultores e Tecnologia, 13080-661, Campinas, Brazil
| | - Thiago A L Burgo
- Department of Chemistry and Environmental Sciences, São Paulo State University (Unesp), 15054-000, São José do Rio Preto, Brazil
| | - Andre Galembeck
- Department of Fundamental Chemistry, Federal University of Pernambuco, 50740-560, Recife, Brazil
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37
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Bairagi A, Pereverzev AY, Tinnemans P, Pidko EA, Roithová J. Electrocatalytic CO 2 Reduction: Monitoring of Catalytically Active, Downgraded, and Upgraded Cobalt Complexes. J Am Chem Soc 2024; 146:5480-5492. [PMID: 38353430 PMCID: PMC10910500 DOI: 10.1021/jacs.3c13290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 01/10/2024] [Accepted: 01/30/2024] [Indexed: 02/29/2024]
Abstract
The premise of most studies on the homogeneous electrocatalytic CO2 reduction reaction (CO2RR) is a good understanding of the reaction mechanisms. Yet, analyzing the reaction intermediates formed at the working electrode is challenging and not always attainable. Here, we present a new, general approach to studying the reaction intermediates applied for CO2RR catalyzed by a series of cobalt complexes. The cobalt complexes were based on the TPA-ligands (TPA = tris(2-pyridylmethyl)amine) modified by amino groups in the secondary coordination sphere. By combining the electrochemical experiments, electrochemistry-coupled electrospray ionization mass spectrometry, with density functional theory (DFT) calculations, we identify and spectroscopically characterize the key reaction intermediates in the CO2RR and the competing hydrogen-evolution reaction (HER). Additionally, the experiments revealed the rarely reported in situ changes in the secondary coordination sphere of the cobalt complexes by the CO2-initiated transformation of the amino substituents to carbamates. This launched an even faster alternative HER pathway. The interplay of three catalytic cycles, as derived from the experiments and supported by the DFT calculations, explains the trends that cobalt complexes exhibit during the CO2RR and HER. Additionally, this study demonstrates the need for a molecular perspective in the electrocatalytic activation of small molecules efficiently obtained by the EC-ESI-MS technique.
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Affiliation(s)
- Abhinav Bairagi
- Institute
for Molecules and Materials, Radboud University, Heyendaalseweg 135, Nijmegen 6525 AJ, The Netherlands
| | - Aleksandr Y. Pereverzev
- Institute
for Molecules and Materials, Radboud University, Heyendaalseweg 135, Nijmegen 6525 AJ, The Netherlands
| | - Paul Tinnemans
- Institute
for Molecules and Materials, Radboud University, Heyendaalseweg 135, Nijmegen 6525 AJ, The Netherlands
| | - Evgeny A. Pidko
- Inorganic
Systems Engineering Group, Department of Chemical Engineering, Faculty
of Applied Sciences, Delft University of
Technology, Delft 2629 HZ, The Netherlands
| | - Jana Roithová
- Institute
for Molecules and Materials, Radboud University, Heyendaalseweg 135, Nijmegen 6525 AJ, The Netherlands
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38
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Liu CY, Chen Y, Hu J. Identification of the Electrogenerated Hidden Nitrenium Ions by In Situ Mass Spectrometry. Anal Chem 2024; 96:3354-3361. [PMID: 38295431 DOI: 10.1021/acs.analchem.3c04315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2024]
Abstract
The identification of the electrogenerated reactive intermediates is essential for an in-depth understanding of the electroredox processes. Although various short-lived intermediates are well characterized by coupling electrochemistry with mass spectrometry (EC/MS), many electrogenerated transient species (τ < 1 μs) are still rarely captured by the currently available EC/MS approaches. Here, we present a low-delay coupling device, which was constructed by decorating a microelectrode into the front tip of a microsized ion emitter. For the first time, the in situ detection of a previously hidden intermediate, i.e., the transient nitrenium ion of carbazole (τ = 333 ns), was achieved. The electrochemical generation of indole nitrenium ion, whose half-life is estimated to be shorter compared to the carbazole nitrenium ion due to less resonance stabilization, was also confirmed by direct observation. This clog-free microelectrode/ion emitter is cheap and easy to fabricate and offers a general and powerful approach to monitoring the fast reactions of electrogenerated reactive intermediates. We believe that our integrated EC/MS approach holds substantial potential for broad applicability, particularly in probing the intricate and ultrafast electroredox processes occurring at the electrode-solution interface.
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Affiliation(s)
- Chun-Yan Liu
- School of Pharmacy, Nanjing Medical University, Nanjing 211166, P. R. China
| | - Yun Chen
- School of Pharmacy, Nanjing Medical University, Nanjing 211166, P. R. China
| | - Jun Hu
- School of Pharmacy, Nanjing Medical University, Nanjing 211166, P. R. China
- School of Life Sciences and Health Engineering, Jiangnan University, Wuxi 214122, P. R. China
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39
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Martins-Costa MTC, Ruiz-López MF. Reactivity of Monoethanolamine at the Air-Water Interface and Implications for CO 2 Capture. J Phys Chem B 2024; 128:1289-1297. [PMID: 38279927 DOI: 10.1021/acs.jpcb.3c06856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2024]
Abstract
The development of CO2-capture technologies is key to mitigating climate change due to anthropogenic greenhouse gas emissions. These cover a number of technologies designed to reduce the level of CO2 emitted into the atmosphere or to eliminate CO2 from ambient air. In this context, amine-based sorbents in aqueous solutions are broadly used in most advanced separation techniques currently implemented in industrial applications. It has been reported that the gas/liquid interface plays an important role in the early stages of the capture process, but how the interface influences the chemistry is still a matter of debate. With the help of first-principles molecular dynamics simulations, we show that monoethanolamine (MEA), a prototypical sorbent molecule, has a weak affinity for the air-water interface, where in addition it exhibits a lower nucleophilicity compared to bulk solution. The change in reactivity is due to the combination of structural and electronic factors, namely, the shift of the conformational equilibrium and the stabilization of the N-atom lone pair. Based on these results, strategies for improving the efficiency of alkanolamine sorbents are proposed.
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Affiliation(s)
- Marilia T C Martins-Costa
- Laboratoire de Physique et Chimie Théoriques, UMR CNRS 7019, University of Lorraine, CNRS, BP 70239, 54506 Vandoeuvre-lès-Nancy, France
| | - Manuel F Ruiz-López
- Laboratoire de Physique et Chimie Théoriques, UMR CNRS 7019, University of Lorraine, CNRS, BP 70239, 54506 Vandoeuvre-lès-Nancy, France
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40
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Paulson AE, Larson EA, Lee YJ. Mobilized Electrospray Device for On-Tissue Chemical Derivatization in MALDI-MS Imaging. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2024; 35:205-213. [PMID: 38147682 DOI: 10.1021/jasms.3c00290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2023]
Abstract
Applying solutions of a matrix or derivatization agent via microdroplets is a common sample preparation technique for matrix-assisted laser desorption/ionization-mass spectrometry imaging (MALDI-MSI) experiments. Mobilized nebulizer sprayers are commonly used to create a homogeneous matrix or reagent layer across large surfaces. Electrospray devices have also been used to produce microdroplets for the same purpose but are rarely used for large tissues due to their immobility. Herein, we present a movable electrospray device that can be used for large tissue sample preparation through a simple modification to an automatic commercial nebulizer device. As demonstrated for on-tissue chemical derivatization (OTCD) with Girard's reagent T using a mimetic tissue model, the sprayer has the additional benefit of being able to investigate reaction acceleration in OTCD when comparing electrostatically charged spray to electrostatically neutral spray. Finally, MALDI-MSI of fatty aldehydes is successfully demonstrated in rat brain tissues using this device for both OTCD and matrix application.
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Affiliation(s)
- Andrew E Paulson
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | - Evan A Larson
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | - Young Jin Lee
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
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41
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Dong J, Chen J, Wang W, Wei Z, Tian ZQ, Fan FR. Charged Microdroplets as Microelectrochemical Cells for CO 2 Reduction and C-C Coupling. J Am Chem Soc 2024; 146:2227-2236. [PMID: 38224553 DOI: 10.1021/jacs.3c12586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2024]
Abstract
Charged microdroplets offer novel electrochemical environments, distinct from traditional solid-liquid or solid-liquid-gas interfaces, due to the intense electric fields at liquid-gas interfaces. In this study, we propose that charged microdroplets serve as microelectrochemical cells (MECs), enabling unique electrochemical reactions at the gas-liquid interface. Using electrospray-generated microdroplets, we achieved multielectron CO2 reduction and C-C coupling to synthesize ethanol using molecular catalysts. These catalysts effectively harness and relay electrons, enhancing the longevity of solvated electrons and enabling multielectron reactions. Importantly, we revealed the intrinsic relationship between the size and charge density of a MEC and its reaction selectivity. Employing in situ mass spectrometry, we identified reaction intermediates (molecular catalyst adducts with HCOO) and oxidation products, elucidating the CO2 reduction mechanism and the comprehensive reaction procedure. Our research underscores the promising role of charged microdroplets in pioneering new electrochemical systems.
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Affiliation(s)
- Jianing Dong
- State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM, College of Chemistry and Chemical Engineering, Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen University, Xiamen 361005, China
| | - Jianxiong Chen
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China
| | - Wenxin Wang
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China
| | - Zhenwei Wei
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China
| | - Zhong-Qun Tian
- State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM, College of Chemistry and Chemical Engineering, Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen University, Xiamen 361005, China
| | - Feng Ru Fan
- State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM, College of Chemistry and Chemical Engineering, Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen University, Xiamen 361005, China
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42
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Yang F, Urban RD, Lorenz J, Griebel J, Koohbor N, Rohdenburg M, Knorke H, Fuhrmann D, Charvat A, Abel B, Azov VA, Warneke J. Control of Intermediates and Products by Combining Droplet Reactions and Ion Soft-Landing. Angew Chem Int Ed Engl 2024; 63:e202314784. [PMID: 37917653 DOI: 10.1002/anie.202314784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 11/01/2023] [Accepted: 11/02/2023] [Indexed: 11/04/2023]
Abstract
Despite being recognized primarily as an analytical technique, mass spectrometry also has a large potential as a synthetic tool, enabling access to advanced synthetic routes by reactions in charged microdroplets or ionic thin layers. Such reactions are special and proceed primarily at surfaces of droplets and thin layers. Partial solvation of the reactants is usually considered to play an important role for reducing the activation barrier, but many mechanistic details still need to be clarified. In our study, we showcase the synergy between two sequentially applied "preparative mass spectrometry" methods: initiating accelerated reactions within microdroplets during electrospray ionization to generate gaseous ionic intermediates in high abundance, which are subsequently mass-selected and soft-landed to react with a provided reagent on a substrate. This allows the generation of products at a nanomolar scale, amenable to further characterization. In this proof-of-concept study, the contrasting reaction pathways between intrinsically neutral and pre-charged reagents, respectively, both in microdroplets and in layers generated by ion soft-landing are investigated. This provides new insights into the role of partially solvated reagents at microdroplet surfaces for increased reaction rates. Additionally, further insights into reactions of ions of the same polarity under various conditions is obtained.
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Affiliation(s)
- Fangshun Yang
- Leibniz Institute of Surface Engineering (IOM), Permoserstrasse 15, 04318, Leipzig, Germany
| | - Raphael D Urban
- Leibniz Institute of Surface Engineering (IOM), Permoserstrasse 15, 04318, Leipzig, Germany
| | - Jonas Lorenz
- Leibniz Institute of Surface Engineering (IOM), Permoserstrasse 15, 04318, Leipzig, Germany
| | - Jan Griebel
- Leibniz Institute of Surface Engineering (IOM), Permoserstrasse 15, 04318, Leipzig, Germany
| | - Nima Koohbor
- Leibniz Institute of Surface Engineering (IOM), Permoserstrasse 15, 04318, Leipzig, Germany
| | - Markus Rohdenburg
- Wilhelm-Ostwald-Institute for Physical and Theoretical Chemistry, University Leipzig, Linnéstrasse 2, 04103, Leipzig, Germany
| | - Harald Knorke
- Wilhelm-Ostwald-Institute for Physical and Theoretical Chemistry, University Leipzig, Linnéstrasse 2, 04103, Leipzig, Germany
| | - Daniel Fuhrmann
- Institute for Inorganic Chemistry, University Leipzig, Johannisallee 29, 04103, Leipzig, Germany
| | - Ales Charvat
- Leibniz Institute of Surface Engineering (IOM), Permoserstrasse 15, 04318, Leipzig, Germany
- Institute of Chemical Technology, University Leipzig, 04103, Leipzig, Germany
| | - Bernd Abel
- Leibniz Institute of Surface Engineering (IOM), Permoserstrasse 15, 04318, Leipzig, Germany
- Institute of Chemical Technology, University Leipzig, 04103, Leipzig, Germany
| | - Vladimir A Azov
- Department of Chemistry, University of the Free State, 9300, Bloemfontein, South Africa
| | - Jonas Warneke
- Leibniz Institute of Surface Engineering (IOM), Permoserstrasse 15, 04318, Leipzig, Germany
- Wilhelm-Ostwald-Institute for Physical and Theoretical Chemistry, University Leipzig, Linnéstrasse 2, 04103, Leipzig, Germany
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43
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Qiu L, Cooks RG. Oxazolone mediated peptide chain extension and homochirality in aqueous microdroplets. Proc Natl Acad Sci U S A 2024; 121:e2309360120. [PMID: 38165938 PMCID: PMC10786291 DOI: 10.1073/pnas.2309360120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Accepted: 11/20/2023] [Indexed: 01/04/2024] Open
Abstract
Peptide formation from amino acids is thermodynamically unfavorable but a recent study provided evidence that the reaction occurs at the air/solution interfaces of aqueous microdroplets. Here, we show that i) the suggested amino acid complex in microdroplets undergoes dehydration to form oxazolone; ii) addition of water to oxazolone forms the dipeptide; and iii) reaction of oxazolone with other amino acids forms tripeptides. Furthermore, the chirality of the reacting amino acids is preserved in the oxazolone product, and strong chiral selectivity is observed when converting the oxazolone to tripeptide. This last fact ensures that optically impure amino acids will undergo chain extension to generate pure homochiral peptides. Peptide formation in bulk by wet-dry cycling shares a common pathway with the microdroplet reaction, both involving the oxazolone intermediate.
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Affiliation(s)
- Lingqi Qiu
- Department of Chemistry, Purdue University, West Lafayette, IN47907
| | - R. Graham Cooks
- Department of Chemistry, Purdue University, West Lafayette, IN47907
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44
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De Angelis M, Managò M, Pepi F, Salvitti C, Troiani A, Villani C, Ciogli A. Stereoselectivity in electrosprayed confined volumes: asymmetric synthesis of warfarin by diamine organocatalysts in microdroplets and thin films. RSC Adv 2024; 14:1576-1580. [PMID: 38179090 PMCID: PMC10765477 DOI: 10.1039/d3ra07975a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Accepted: 12/15/2023] [Indexed: 01/06/2024] Open
Abstract
The asymmetric synthesis of warfarin in microdroplets and thin films generated by an electrospray ionization (ESI) source is reported. This is one of the first examples of an enantioselective organocatalyzed reaction in electrosprayed confined volumes. The optimal conditions in terms of system setting were established for this reaction.
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Affiliation(s)
- Martina De Angelis
- Department of Chemistry and Drug Technologies, Sapienza University of Rome Piazzale Aldo Moro 5 00185 Roma Italy
| | - Marta Managò
- Department of Chemistry and Drug Technologies, Sapienza University of Rome Piazzale Aldo Moro 5 00185 Roma Italy
| | - Federico Pepi
- Department of Chemistry and Drug Technologies, Sapienza University of Rome Piazzale Aldo Moro 5 00185 Roma Italy
| | - Chiara Salvitti
- Department of Chemistry and Drug Technologies, Sapienza University of Rome Piazzale Aldo Moro 5 00185 Roma Italy
| | - Anna Troiani
- Department of Chemistry and Drug Technologies, Sapienza University of Rome Piazzale Aldo Moro 5 00185 Roma Italy
| | - Claudio Villani
- Department of Chemistry and Drug Technologies, Sapienza University of Rome Piazzale Aldo Moro 5 00185 Roma Italy
| | - Alessia Ciogli
- Department of Chemistry and Drug Technologies, Sapienza University of Rome Piazzale Aldo Moro 5 00185 Roma Italy
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45
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Zeng B, Yang H, Xu BB, Lohse D, Zhang X. Launching a Drop via Interplay of Buoyancy and Stick-Jump Dissolution. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2303177. [PMID: 37726248 DOI: 10.1002/smll.202303177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 08/22/2023] [Indexed: 09/21/2023]
Abstract
According to Archimedes' principle, a submerged object with a density lower than that of aqueous acid solution is more buoyant than a smaller one. In this work, a remarkable phenomenon is reported wherein a dissolving drop on a substrate rises in the water only after it has diminished to a much smaller size, though the buoyancy is smaller. The drop consisting of a polymer solution reacts with the acid in the surrounding, yielding a water-soluble product. During drop dissolution, water-rich microdroplets form within the drop, merging with the external aqueous phase along the drop-substrate boundary. Two key elements determine the drop rise dynamics. The first is the stick-jump behavior during drop dissolution. The second is that buoyancy exerts a strong enough force on the drop at an Archimedean number greater than 1, while the stick-jump behavior is ongoing. The time of the drop rise is controlled by the initial size and the reaction rate of the drop. This novel mechanism for programmable drop rise may be beneficial for many future applications, such as microfluidics, microrobotics, and device engineering where the spontaneous drop detachment may be utilized to trigger a cascade of events in a dense medium.
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Affiliation(s)
- Binglin Zeng
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, T6G 1H9, Canada
| | - Haichang Yang
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, T6G 1H9, Canada
- School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou, 221116, China
| | - Ben Bin Xu
- Mechanical and Construction Engineering, Faculty of Engineering and Environment, Northumbria University, Newcastle Upon Tyne, NE1 8ST, UK
| | - Detlef Lohse
- Physics of Fluids Group, Max Planck Center for Complex Fluid Dynamics, University of Twente, Enschede, 7500 AE, The Netherlands
- Max Planck Institute for Dynamics and Self-Organization, 37077, Göttingen, Germany
| | - Xuehua Zhang
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, T6G 1H9, Canada
- Physics of Fluids Group, Max Planck Center for Complex Fluid Dynamics, University of Twente, Enschede, 7500 AE, The Netherlands
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46
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Edwards M, Freitas DP, Hirtzel EA, White N, Wang H, Davidson LA, Chapkin RS, Sun Y, Yan X. Interfacial Electromigration for Analysis of Biofluid Lipids in Small Volumes. Anal Chem 2023; 95:18557-18563. [PMID: 38050376 PMCID: PMC10862378 DOI: 10.1021/acs.analchem.3c04309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2023] [Revised: 11/19/2023] [Accepted: 11/21/2023] [Indexed: 12/06/2023]
Abstract
Lipids are important biomarkers within the field of disease diagnostics and can serve as indicators of disease progression and predictors of treatment effectiveness. Although lipids can provide important insight into how diseases initiate and progress, mass spectrometric methods for lipid characterization and profiling are limited due to lipid structural diversity, particularly the presence of various lipid isomers. Moreover, the difficulty of handling small-volume samples exacerbates the intricacies of biological analyses. In this work, we have developed a strategy that electromigrates a thin film of a small-volume biological sample directly to the air-liquid interface formed at the tip of a theta capillary. Importantly, we seamlessly integrated in situ biological lipid extraction with accelerated chemical derivatization, enabled by the air-liquid interface, and conducted isomeric structural characterization within a unified platform utilizing theta capillary nanoelectrospray ionization mass spectrometry, all tailored for small-volume sample analysis. We applied this unified platform to the analysis of lipids from small-volume human plasma and Alzheimer's disease mouse serum samples. Accelerated electro-epoxidation of unsaturated lipids at the interface allowed us to characterize lipid double-bond positional isomers. The unique application of electromigration of a thin film to the air-liquid interface in combination with accelerated interfacial reactions holds great potential in small-volume sample analysis for disease diagnosis and prevention.
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Affiliation(s)
- Madison
E. Edwards
- Department
of Chemistry, Texas A&M University, 580 Ross Street, College Station, Texas 77843, United States
| | - Dallas P. Freitas
- Department
of Chemistry, Texas A&M University, 580 Ross Street, College Station, Texas 77843, United States
| | - Erin A. Hirtzel
- Department
of Chemistry, Texas A&M University, 580 Ross Street, College Station, Texas 77843, United States
| | - Nicholas White
- Department
of Chemistry, Texas A&M University, 580 Ross Street, College Station, Texas 77843, United States
| | - Hongying Wang
- Department
of Nutrition, Texas A&M University, 373 Olsen Blvd, College Station, Texas 77845, United States
| | - Laurie A. Davidson
- Department
of Nutrition, Texas A&M University, 373 Olsen Blvd, College Station, Texas 77845, United States
| | - Robert S. Chapkin
- Department
of Nutrition, Texas A&M University, 373 Olsen Blvd, College Station, Texas 77845, United States
| | - Yuxiang Sun
- Department
of Nutrition, Texas A&M University, 373 Olsen Blvd, College Station, Texas 77845, United States
| | - Xin Yan
- Department
of Chemistry, Texas A&M University, 580 Ross Street, College Station, Texas 77843, United States
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47
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Stares DL, Szumna A, Schalley CA. Encapsulation in Charged Droplets Generates Distorted Host-Guest Complexes. Chemistry 2023; 29:e202302112. [PMID: 37724745 DOI: 10.1002/chem.202302112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 09/18/2023] [Accepted: 09/19/2023] [Indexed: 09/21/2023]
Abstract
The ability of various hydrogen-bonded resorcinarene-based capsules to bind α,ω-alkylbisDABCOnium (DnD) guests of different lengths was investigated in solution and in the gas-phase. While no host-guest interactions were detected in solution, encapsulation could be achieved in the charged droplets formed during electrospray ionisation (ESI). This included guests, which are far too long in their most stable conformation to fit inside the cavity of the capsules. A combination of three mass spectrometric techniques, namely, collision-induced dissociation, hydrogen/deuterium exchange, and ion-mobility mass spectrometry, together with computational modelling allow us to determine the binding mode of the DnD guests inside the cavity of the capsules. Significant distortions of the guest into horseshoe-like arrangements are required to optimise cation-π interactions with the host, which also adopt distorted geometries with partially open hydrogen-bonding seams when binding longer guests. Such quasi "spring-loaded" capsules can form in the charged droplets during the ESI process as there is no competition between guest encapsulation and ion pair formation with the counterions that preclude encapsulation in solution. The encapsulation complexes are sufficiently stable in the gas-phase - even when strained - because non-covalent interactions significantly strengthen in the absence of solvent.
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Affiliation(s)
- Daniel L Stares
- Institut für Chemie und Biochemie, Freie Universität Berlin, Arnimallee 20, 14195, Berlin, Germany
| | - Agnieszka Szumna
- Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, Warsaw, Poland
| | - Christoph A Schalley
- Institut für Chemie und Biochemie, Freie Universität Berlin, Arnimallee 20, 14195, Berlin, Germany
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48
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Salvitti C, de Petris G, Troiani A, Managò M, Di Noi A, Ricci A, Pepi F. Sulfuric Acid Catalyzed Esterification of Amino Acids in Thin Film. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2023; 34:2748-2754. [PMID: 37904271 DOI: 10.1021/jasms.3c00284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/01/2023]
Abstract
The esterification reaction of different amino acids with methanol catalyzed by H2SO4 was first studied in the small volume of thin films generated by ESI microdroplet deposition. The reaction is promoted by the pneumatic spray of the ESI source and reaches its maximum efficiency at a thin film temperature of 70 °C. Selective esterification of the COOH moiety was demonstrated. Microdroplet size and thin film volume and lifetime are critical parameters that influenced the reaction outcome. As expected, l-tyrosine and l-phenylalanine having aromatic side chain substituents were the most reactive amino acids, reaching absolute yields of around 40-50%. The amino acid esterification catalyzed by H2SO4 in a thin film occurs under synthetic conditions in which the same reaction in the bulk is not observed.
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Affiliation(s)
- Chiara Salvitti
- "Sapienza" University of Rome, Department of Chemistry and Drug Technologies P.le Aldo Moro 5, 00185 Rome, Italy
| | - Giulia de Petris
- "Sapienza" University of Rome, Department of Chemistry and Drug Technologies P.le Aldo Moro 5, 00185 Rome, Italy
| | - Anna Troiani
- "Sapienza" University of Rome, Department of Chemistry and Drug Technologies P.le Aldo Moro 5, 00185 Rome, Italy
| | - Marta Managò
- "Sapienza" University of Rome, Department of Chemistry and Drug Technologies P.le Aldo Moro 5, 00185 Rome, Italy
| | - Alessia Di Noi
- "Sapienza" University of Rome, Department of Chemistry and Drug Technologies P.le Aldo Moro 5, 00185 Rome, Italy
| | - Andreina Ricci
- Department of Mathematics and Physics, University of Campania L. Vanvitelli, Viale Lincoln 5, 81100, Caserta, Italy
| | - Federico Pepi
- "Sapienza" University of Rome, Department of Chemistry and Drug Technologies P.le Aldo Moro 5, 00185 Rome, Italy
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49
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Davis BTV, Velyvis A, Vahidi S. Fluorinated Ethylamines as Electrospray-Compatible Neutral pH Buffers for Native Mass Spectrometry. Anal Chem 2023; 95:17525-17532. [PMID: 37997939 DOI: 10.1021/acs.analchem.3c02640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2023]
Abstract
Native electrospray ionization mass spectrometry (ESI-MS) has emerged as a potent tool for examining the native-like structures of macromolecular complexes. Despite its utility, the predominant "buffer" used, ammonium acetate (AmAc) with pKa values of 4.75 for acetic acid and 9.25 for ammonium, provides very little buffering capacity within the physiological pH range of 7.0-7.4. ESI-induced redox reactions alter the pH of the liquid within the ESI capillary. This can result in protein unfolding or weakening of pH-sensitive interactions. Consequently, the discovery of volatile, ESI-compatible buffers, capable of effectively maintaining pH within a physiological range, is of high importance. Here, we demonstrate that 2,2-difluoroethylamine (DFEA) and 2,2,2-trifluoroethylamine (TFEA) offer buffering capacity at physiological pH where AmAc falls short, with pKa values of 7.2 and 5.5 for the conjugate acids of DFEA and TFEA, respectively. Native ESI-MS experiments on model proteins cytochrome c and myoglobin electrosprayed with DFEA and TFEA demonstrated the preservation of noncovalent protein-ligand complexes in the gas phase. Protein stability assays and collision-induced unfolding experiments further showed that neither DFEA nor TFEA destabilized model proteins in solution or in the gas phase. Finally, we demonstrate that multisubunit protein complexes such as alcohol dehydrogenase and concanavalin A can be studied in the presence of DFEA or TFEA using native ESI-MS. Our findings establish DFEA and TFEA as new ESI-compatible neutral pH buffers that promise to bolster the use of native ESI-MS for the analysis of macromolecular complexes, particularly those sensitive to pH fluctuations.
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Affiliation(s)
- Bradley T V Davis
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Algirdas Velyvis
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Siavash Vahidi
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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50
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Li D, Song Y, Li D. Surface charging and electrophoretic behavior of conductive polymer micro-droplets in conductive polymer liquid solutions. Analyst 2023; 148:6315-6324. [PMID: 37947009 DOI: 10.1039/d3an01371e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2023]
Abstract
This study investigates the surface charging and electrophoretic motion of polyethylene glycol-rich (PEG-rich) micro-droplets in dextran-rich solutions or dextran-rich micro-droplets in PEG-rich solutions. The electrophoretic velocities of the droplets were measured in a centimeter-sized chamber under an optical microscope. It was found that the direction of electrophoretic motion of both the PEG-rich droplets and dextran-rich droplets is opposite to the applied electric field, meaning that both the PEG-rich droplets and dextran-rich droplets are negatively charged. The electrophoretic velocity is independent of droplet size but proportional to the electric field strength. Increasing the NaCl concentration reduces the electrophoretic velocity of PEG-rich droplets and increases it for dextran-rich droplets, suggesting different surface charge changes due to ion affinity. The charge densities and velocities are affected by the PEG and dextran mass fractions. Physical models for droplet surface charging under different conditions were proposed to explain the experimental results.
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Affiliation(s)
- Deyu Li
- Department of Marine Engineering, Dalian Maritime University, Dalian, 116026, China.
| | - Yongxin Song
- Department of Marine Engineering, Dalian Maritime University, Dalian, 116026, China.
| | - Dongqing Li
- Department of Mechanical and Mechatronics Engineering, University of Waterloo, Waterloo, ON, N2L 3G1, Canada.
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