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Zheng B, Wu Y, Xue L, Sun J, Liu J, Cheng H. Is Reaction Acceleration of Microdroplet Chemistry Favorable to Controlling the Enantioselectivity? J Org Chem 2023; 88:16186-16195. [PMID: 37948325 DOI: 10.1021/acs.joc.3c01660] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2023]
Abstract
Microdroplet chemistry has been proven to amazingly accelerate many chemical and biological reactions in the past 2 decades. Current microdroplet accelerated reactions are predominantly symmetric synthetic but minorly asymmetric synthetic reactions, where stereoselectivity is scarcely concerned. This study selected unimolecular and bimolecular reactions, multicomponent Passerini reactions, and enzymatic ketone reduction as the model reactions to illustrate whether reaction acceleration of microdroplet chemistry is favorable to retaining a chiral center and controlling the enantioselectivity or not. The results illustrated that microdroplet chemistry did not disrupt pre-existing stereogenic centers in chiral starting materials during reactions but did harm to stereospecificity in asymmetric catalysis by chiral catalysts and chiral organic ligands with the exclusion of enzymatic reactions. Our preliminary study reminds us of more cautions to the product enantioselectivity when conducting asymmetric catalysis in microdroplets. We also hope this study may promote more valuable further research on the stereoselectivity of microdroplet chemistry.
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Affiliation(s)
- Boyu Zheng
- 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
| | - Yikang Wu
- 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
| | - Luyun Xue
- 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
| | - Jiannan Sun
- 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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Song Y, Wu Y, Wu D, Ma X, Jiang S, Peng Z, Zhang C, Yin Y, Guo R. Fluorine-tailed glass fibers for adsorption of volatile perfluorinated compounds via F-F interaction. ENVIRONMENT INTERNATIONAL 2023; 180:108205. [PMID: 37717520 DOI: 10.1016/j.envint.2023.108205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 09/08/2023] [Accepted: 09/11/2023] [Indexed: 09/19/2023]
Abstract
Perfluorinated compounds (PFCs) and their short-chain derivatives are contaminants found globally. Adsorption research on volatile perfluorinated compounds (VPFCs), which are the main PFCs substances that undergo transfer and migration, is particularly important. In this study, new fluorine-containing tail materials (FCTMs) were prepared by combining fluorine-containing tail organic compounds with modified glass fibers. The adsorption effects of these FCTMs were generally stronger than that of pure activated glass fibers without fluorine- tailed, with an adsorption efficiency of up to 86% based on F-F interactions. The results showed that the FCTMs had improved desorption efficiency and reusability, and higher adsorption efficiency compared with that of polyurethane foam. FTGF was applied to the active sampler, and the indoor adsorption of perfluorovaleric acid was up to 2.45 ng/m3. The adsorption kinetics and isotherm simulation results showed that the adsorption process of typical perfluorinated compounds conformed to the second-order kinetics and Langmuir model. Furthermore, Nuclear Magnetic Resonance (NMR) results showed that the chemical shift in the fluorine spectrum was significantly changed by F-F interactions. This research provides basic theoretical data for the study of VPFCs, especially short-chain VPFCs, facilitating improved scientific support for the gas phase analysis of VPFCs in the environment.
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Affiliation(s)
- Yangyang Song
- Hubei Key Laboratory of Environmental and Health Effects of Persistent Toxic Substances, School of Environment and Health, Jianghan University, Wuhan 430056, China
| | - Yawen Wu
- Hubei Key Laboratory of Environmental and Health Effects of Persistent Toxic Substances, School of Environment and Health, Jianghan University, Wuhan 430056, China
| | - Di Wu
- Hubei Key Laboratory of Environmental and Health Effects of Persistent Toxic Substances, School of Environment and Health, Jianghan University, Wuhan 430056, China
| | - Xiaofan Ma
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, International Innovation Center for Forest Chemicals and Materials, College of Materials Science and Engineering, Nanjing Forestry University, Nanjing 210037, China
| | - Shaohua Jiang
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, International Innovation Center for Forest Chemicals and Materials, College of Materials Science and Engineering, Nanjing Forestry University, Nanjing 210037, China.
| | - Zhihao Peng
- School of Medicine, Jianghan University, Wuhan 430056, China
| | - Chunmei Zhang
- Institute of Materials Science and Devices, School of Materials Science and Engineering, Suzhou University of Science and Technology, Suzhou 215009, China
| | - Yongguang Yin
- Hubei Key Laboratory of Environmental and Health Effects of Persistent Toxic Substances, School of Environment and Health, Jianghan University, Wuhan 430056, China
| | - Rui Guo
- Hubei Key Laboratory of Environmental and Health Effects of Persistent Toxic Substances, School of Environment and Health, Jianghan University, Wuhan 430056, China.
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3
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Li Y, Kolasinski KW, Zare RN. Silica particles convert thiol-containing molecules to disulfides. Proc Natl Acad Sci U S A 2023; 120:e2304735120. [PMID: 37590411 PMCID: PMC10450441 DOI: 10.1073/pnas.2304735120] [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: 03/25/2023] [Accepted: 07/14/2023] [Indexed: 08/19/2023] Open
Abstract
Synthetic amorphous silica is a common food additive and a popular cosmetic ingredient. Mesoporous silica particles are also widely studied for their potential use in drug delivery and imaging applications because of their unique properties, such as tunable pore sizes, large surfaces areas, and assumed biocompatibility. Such a nanomaterial, when consisting of pure silicon dioxide, is generally considered to be chemically inert, but in this study, we showed that oxidation yields for different compounds were facilitated by simply incubating aqueous solutions with pure silica particles. Three thiol-containing molecules, L-cysteine, glutathione, and D-penicillamine, were studied separately, and it was found that more than 95% of oxidation happened after incubating any of these compounds with mesoporous silica particles in the dark for a day at room temperature. Oxidation increased over incubation time, and more oxidation was found for particles having larger surface areas. For nonporous silica particles at submicron ranges, yields of oxidation were different based on the structures of molecules, correlating with steric hindrance while accessing surfaces. We propose that the silyloxy radical (SiO•) on silica surfaces is what facilitates oxidation. Density functional theory calculations were conducted for total energy changes for reactions between different aqueous species and silicon dioxide surfaces. These calculations identified two most plausible pathways of the lowest energy to generate SiO• radicals from water radical cations H2O•+ and hydroxyl radicals •OH, previously known to exist at water interfaces.
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Affiliation(s)
- Yangjie Li
- Department of Chemistry, Stanford University, Stanford, CA94305
| | | | - Richard N. Zare
- Department of Chemistry, Stanford University, Stanford, CA94305
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4
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Huang KH, Morato NM, Feng Y, Cooks RG. High-Throughput Diversification of Complex Bioactive Molecules by Accelerated Synthesis in Microdroplets. Angew Chem Int Ed Engl 2023; 62:e202300956. [PMID: 36941213 PMCID: PMC10182919 DOI: 10.1002/anie.202300956] [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: 01/18/2023] [Revised: 03/17/2023] [Accepted: 03/20/2023] [Indexed: 03/23/2023]
Abstract
Late-stage diversification of drug molecules is an important strategy in drug discovery that can be facilitated by reaction screening using high-throughput experimentation. Here we present a rapid method for functionalizing bioactive molecules based on accelerated reactions in microdroplets. Reaction mixtures are nebulized at throughputs better than 1 reaction/second and the accelerated reactions occurring in the microdroplets are followed by desorption electrospray ionization mass spectrometry (DESI-MS). Because the accelerated reactions occur on the millisecond timescale, they allow an overall screening throughput of 1 Hz working at the low nanogram scale. Using this approach, an opioid agonist (PZM21) and an antagonist (naloxone) were diversified using three reactions important in medicinal chemistry: sulfur fluoride exchange (SuFEx) click reactions, imine formation reactions, and ene-type click reactions. Some 269 functionalized analogs of naloxone and PZM21 were generated and characterized by tandem mass spectrometry (MS/MS) after screening over 500 reactions.
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Affiliation(s)
- Kai-Hung Huang
- Department of Chemistry, Purdue University, West Lafayette, IN, USA
| | - Nicolás M Morato
- Department of Chemistry, Purdue University, West Lafayette, IN, USA
| | - Yunfei Feng
- Department of Chemistry, Purdue University, West Lafayette, IN, USA
| | - R Graham Cooks
- Department of Chemistry, Purdue University, West Lafayette, IN, USA
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5
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Sun J, Tan H, Gao Y, Li J, Wei J, Zhang S, Ouyang J, Na N. Confined surface-enhanced indole cation-radical cyclization studied by mass spectrometry. Analyst 2023; 148:262-268. [PMID: 36503912 DOI: 10.1039/d2an01719a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Reactions in confined spaces exhibit unique reactivity, while how the confinement effect enhances reactions remains unclear. Herein, the reaction in the confined space of a nanopipette reactor was examined by in situ nano-electrospray mass spectrometry (nanoESI-MS). The indole cation-radical cyclization was selected as the model reaction, catalyzed by a common visible-light-harvesting complex Ru(bpz)3(PF6)2 (1% eq.) rather than traditional harsh reaction conditions (high temperature or pressure, etc.). As demonstrated by in situ nanoESI-MS, this reaction was readily promoted in the nanopipette under mild conditions, while it was inefficient in both normal flasks and microdroplets. Both experimental and theoretical evidence demonstrated the formation of concentrated Ru(II)-complexes on the inner surface of the nanopipette, which facilitated the accelerated reactions. As a result, dissociative reactive cation radicals with lower HOMO-LUMO gap were generated from the Ru(II)-complexes by ligand-to-metal charge transfer (LMCT). Furthermore, the crucial cation radical intermediates were captured and dynamically monitored via in situ nanoESI-MS, responsible for the electronically matched [4 + 2] cycloaddition and subsequent intramolecular dehydrogenation. This work inspires a deeper understanding of the unique reactions in confined spaces.
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Affiliation(s)
- Jianghui Sun
- Key Laboratory of Radiopharmaceuticals, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China.
| | - Hongwei Tan
- Key Laboratory of Radiopharmaceuticals, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China.
| | - Yixuan Gao
- Key Laboratory of Radiopharmaceuticals, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China.
| | - Jingjing Li
- Key Laboratory of Radiopharmaceuticals, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China.
| | - Juanjuan Wei
- Key Laboratory of Radiopharmaceuticals, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China.
| | - Shengxi Zhang
- Key Laboratory of Radiopharmaceuticals, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China.
| | - Jin Ouyang
- Key Laboratory of Radiopharmaceuticals, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China.
| | - Na Na
- Key Laboratory of Radiopharmaceuticals, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China.
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6
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Zhang K, He N, Zhang C, Wang X. Erasable polymer hydrogel wells. Colloids Surf A Physicochem Eng Asp 2022. [DOI: 10.1016/j.colsurfa.2022.129431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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7
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Water-solid contact electrification causes hydrogen peroxide production from hydroxyl radical recombination in sprayed microdroplets. Proc Natl Acad Sci U S A 2022; 119:e2209056119. [PMID: 35914139 PMCID: PMC9371641 DOI: 10.1073/pnas.2209056119] [Citation(s) in RCA: 47] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Contact electrification between water and a solid surface is crucial for physicochemical processes at water-solid interfaces. However, the nature of the involved processes remains poorly understood, especially in the initial stage of the interface formation. Here we report that H2O2 is spontaneously produced from the hydroxyl groups on the solid surface when contact occurred. The density of hydroxyl groups affects the H2O2 yield. The participation of hydroxyl groups in H2O2 generation is confirmed by mass spectrometric detection of 18O in the product of the reaction between 4-carboxyphenylboronic acid and 18O-labeled H2O2 resulting from 18O2 plasma treatment of the surface. We propose a model for H2O2 generation based on recombination of the hydroxyl radicals produced from the surface hydroxyl groups in the water-solid contact process. Our observations show that the spontaneous generation of H2O2 is universal on the surfaces of soil and atmospheric fine particles in a humid environment.
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8
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Akaike K, Hosokai A, Nagashima H, Wei Q, Hosokai T. Chemical reactions of graphitic carbon nitride films with glass surfaces and their impact on photocatalytic activity. Phys Chem Chem Phys 2022; 24:17504-17515. [PMID: 35838187 DOI: 10.1039/d2cp01677j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Thin films of graphitic carbon nitride (g-CN), a visible-light-driven photocatalyst, have recently attracted interest for application in photoelectrochemical cells for water splitting and high-throughput photocatalysis. In typical syntheses, g-CN films are formed by heating the nitrogen-rich precursor and substrate to 500-600 °C. The heated substrate should affect the polycondensation of the precursor and thereby alter the properties of the g-CN film. In this paper, we demonstrate that soda-lime glass, such as commercial glass slides, modifies the chemical structure of g-CN. The terminal amino groups of g-CN are partially substituted with cyanamide and hydroxyl groups. The electron-withdrawing groups provide the energy offsets of the frontier orbitals between the modified and unmodified molecules, facilitating exciton dissociation. After alkali metals are removed, the modified g-CN film exhibits a faster photodegradation of methyl orange compared with a melon film. The simple protocol to activate a g-CN film without co-catalysts paves a new way to enhance photocatalytic activity via selections of substrates, including waste glass.
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Affiliation(s)
- Kouki Akaike
- Nanomaterials Research Institute, National Institute of Advanced Industrial Science and Technology, Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan.
| | - Ayako Hosokai
- Nanomaterials Research Institute, National Institute of Advanced Industrial Science and Technology, Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan.
| | - Hiroki Nagashima
- Interdisciplinary Research Center for Catalytic Chemistry, National Institute of Advanced Industrial Science and Technology, Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan
| | - Qingshuo Wei
- Nanomaterials Research Institute, National Institute of Advanced Industrial Science and Technology, Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan.
| | - Takuya Hosokai
- National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology, Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan
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9
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Nielsen MM, Pedersen CM. Vessel effects in organic chemical reactions; a century-old, overlooked phenomenon. Chem Sci 2022; 13:6181-6196. [PMID: 35733904 PMCID: PMC9159102 DOI: 10.1039/d2sc01125e] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Accepted: 05/03/2022] [Indexed: 12/01/2022] Open
Abstract
One of the most intriguing aspects of synthetic chemistry is the interplay of numerous dependent and independent variables en route to achieve a successful, high-yielding chemical transformation. The experienced synthetic chemist will probe many of these variables during reaction development and optimization, which will routinely involve investigation of reaction temperature, solvent, stoichiometry, concentration, time, choice of catalyst, addition sequence or quenching conditions just to name some commonly addressed variables. Remarkably, little attention is typically given to the choice of reaction vessel material as the surface of common laboratory borosilicate glassware is, incorrectly, assumed to be chemically inert. When reviewing the scientific literature, careful consideration of the vessel material is typically only given during the use of well-known glass-etching reagents such as HF, which is typically only handled in HF-resistant, polyfluorinated polymer vessels. However, there are examples of chemical transformations that do not involve such reagents but are still clearly influenced by the choice of reaction vessel material. In the following review, we wish to condense the most significant examples of vessel effects during chemical transformations as well as observations of container-dependent stability of certain molecules. While the primary focus is on synthetic organic chemistry, relevant examples from inorganic chemistry, polymerization reactions, atmospheric chemistry and prebiotic chemistry are also covered.
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Affiliation(s)
- Michael Martin Nielsen
- Department of Chemistry, University of Copenhagen Universitetsparken 5 2100 Copenhagen O Denmark
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10
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Qiu L, Morato NM, Huang KH, Cooks RG. Spontaneous Water Radical Cation Oxidation at Double Bonds in Microdroplets. Front Chem 2022; 10:903774. [PMID: 35559217 PMCID: PMC9086510 DOI: 10.3389/fchem.2022.903774] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Accepted: 04/11/2022] [Indexed: 12/20/2022] Open
Abstract
Spontaneous oxidation of compounds containing diverse X=Y moieties (e.g., sulfonamides, ketones, esters, sulfones) occurs readily in organic-solvent microdroplets. This surprising phenomenon is proposed to be driven by the generation of an intermediate species [M+H2O]+·: a covalent adduct of water radical cation (H2O+·) with the reactant molecule (M). The adduct is observed in the positive ion mass spectrum while its formation in the interfacial region of the microdroplet (i.e., at the air-droplet interface) is indicated by the strong dependence of the oxidation product formation on the spray distance (which reflects the droplet size and consequently the surface-to-volume ratio) and the solvent composition. Importantly, based on the screening of a ca. 21,000-compound library and the detailed consideration of six functional groups, the formation of a molecular adduct with the water radical cation is a significant route to ionization in positive ion mode electrospray, where it is favored in those compounds with X=Y moieties which lack basic groups. A set of model monofunctional systems was studied and in one case, benzyl benzoate, evidence was found for oxidation driven by hydroxyl radical adduct formation followed by protonation in addition to the dominant water radical cation addition process. Significant implications of molecular ionization by water radical cations for oxidation processes in atmospheric aerosols, analytical mass spectrometry and small-scale synthesis are noted.
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Huang KH, Ghosh J, Xu S, Cooks RG. Late-Stage Functionalization and Characterization of Drugs by High-Throughput Desorption Electrospray Ionization Mass Spectrometry. Chempluschem 2022; 87:e202100449. [PMID: 34985208 DOI: 10.1002/cplu.202100449] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 11/24/2021] [Indexed: 12/15/2022]
Abstract
Late-stage functionalization (LSF) of drug molecules is an approach to generate modified molecules that retain functional groups present in the active drugs. Here, we report a study that seeks to characterize the potential value of high-throughput desorption electrospray ionization mass spectrometry (HT DESI-MS) for small-scale rapid LSF. In conventional route screening, HT-based DESI-MS provides contactless, rapid analysis, reliable and reproducible data, minimal sample requirement, and exceptional tolerance to high salt concentrations. Ezetimibe (E), an established hypertension drug, is targeted for modification by LSF. C-H alkenylation and azo-click reactions are utilized to explore this approach to synthesis and analytical characterization. The effect of choice of reactant, stoichiometry, catalyst, and solvent are studied for both reactions using high throughput DESI-MS experiments. Optimum conditions for the formation of LSF products are established with identification by tandem mass spectrometry (MS/MS).
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Affiliation(s)
- Kai-Hung Huang
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN, 47907, USA
| | - Jyotirmoy Ghosh
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN, 47907, USA
| | - Shiqing Xu
- Department of Chemistry, Texas A&M University, 580 Ross Street, College Station, TX, 77843, USA
| | - R Graham Cooks
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN, 47907, USA
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Ramler J, Schwarzmann J, Stoy A, Lichtenberg C. Two Faces of the Bi−O Bond: Photochemically
and
Thermally Induced Dehydrocoupling for Si−O Bond Formation. Eur J Inorg Chem 2021; 2022:e202100934. [PMID: 35873275 PMCID: PMC9300068 DOI: 10.1002/ejic.202100934] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 11/23/2021] [Indexed: 11/27/2022]
Abstract
The diorgano(bismuth)alcoholate [Bi((C6H4CH2)2S)OPh] (1‐OPh) has been synthesized and fully characterized. Stoichiometric reactions, UV/Vis spectroscopy, and (TD‐)DFT calculations suggest its susceptibility to homolytic and heterolytic Bi−O bond cleavage under given reaction conditions. Using the dehydrocoupling of silanes with either TEMPO or phenol as model reactions, the catalytic competency of 1‐OPh has been investigated (TEMPO=(tetramethyl‐piperidin‐1‐yl)‐oxyl). Different reaction pathways can deliberately be addressed by applying photochemical or thermal reaction conditions and by choosing radical or closed‐shell substrates (TEMPO vs. phenol). Applied analytical techniques include NMR, UV/Vis, and EPR spectroscopy, mass spectrometry, single‐crystal X‐ray diffraction analysis, and (TD)‐DFT calculations.
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Affiliation(s)
- Jacqueline Ramler
- Institute of Inorganic Chemistry Julius-Maximilians-University Würzburg Am Hubland 97074 Würzburg Germany
| | - Johannes Schwarzmann
- Institute of Inorganic Chemistry Julius-Maximilians-University Würzburg Am Hubland 97074 Würzburg Germany
| | - Andreas Stoy
- Institute of Inorganic Chemistry Julius-Maximilians-University Würzburg Am Hubland 97074 Würzburg Germany
- Philipps-Universität Marburg Fachbereich Chemie Hans-Meerwein-Str. 4 35032 Marburg Germany
| | - Crispin Lichtenberg
- Institute of Inorganic Chemistry Julius-Maximilians-University Würzburg Am Hubland 97074 Würzburg Germany
- Philipps-Universität Marburg Fachbereich Chemie Hans-Meerwein-Str. 4 35032 Marburg Germany
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