51
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Garrett P, Shirley JC, Baiz CR. Forced Interactions: Ionic Polymers at Charged Surfactant Interfaces. J Phys Chem B 2023; 127:2829-2836. [PMID: 36926899 DOI: 10.1021/acs.jpcb.2c08636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2023]
Abstract
Characterizing electrostatic interactions at heterogeneous interfaces is critical for developing a fundamental description of the dynamic processes at charged interfaces. Water-in-oil reverse micelles (RMs) offer a high degree of tunability across composition, polarity, and temperature, making them ideal systems for studying interactions at heterogeneous liquid-liquid interfaces. In the present study, we use a combination of ultrafast two-dimensional infrared spectroscopy and molecular dynamics (MD) simulations to determine the picosecond interfacial dynamics in RMs containing binary compositions of sorbitan monostearate and anionic or cationic cosurfactants, which are used to tune the ratio of charged to nonionic surfactants at the interface. The positively charged polyethylenimine (PEI) polymer is encapsulated within the RMs, and the carbonyl stretching mode of sorbitan monostearate reports on the interfacial hydrogen-bond populations and dynamics. The results show that hydrogen-bond populations are altered through the inclusion of both negatively and positively charged cosurfactants. Charged surfactants increase interfacial water penetration into the surfactant layer, and the surface localization of polymers decreases water penetration. Local hydrogen-bond dynamics undergo a slowdown with the inclusion of charged surfactants, and the encapsulation of polymers results in similar effects, irrespective of the charge.
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Affiliation(s)
- Paul Garrett
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Joseph C Shirley
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Carlos R Baiz
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
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52
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Datar A, Wright C, Matthews DA. Theoretical Investigation of the X-ray Stark Effect in Small Molecules. J Phys Chem A 2023; 127:1576-1587. [PMID: 36787229 DOI: 10.1021/acs.jpca.2c08311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
We have studied the Stark effect in the soft x-ray region for various small molecules by calculating the field-dependent x-ray absorption spectra. This effect is explained in terms of the response of molecular orbitals (core and valence), the molecular dipole moment, and the molecular geometry to the applied electric field. A number of consistent trends are observed linking the computed shifts in absorption energies and intensities with specific features of the molecular electronic structure. We find that both the virtual molecular orbitals (valence and/or Rydberg) as well as the core orbitals contribute to observed trends in a complementary fashion. This initial study highlights the potential impact of x-ray Stark spectroscopy as a tool to study electronic structure and environmental perturbations at a submolecular scale.
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Affiliation(s)
- Avdhoot Datar
- Department of Chemistry, Southern Methodist University, Dallas, Texas 75275, United States
| | - Catherine Wright
- Department of Chemistry, Southern Methodist University, Dallas, Texas 75275, United States
| | - Devin A Matthews
- Department of Chemistry, Southern Methodist University, Dallas, Texas 75275, United States
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53
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Chen S, Xiao YH, Qin M, Zhou G, Dong R, Devasenathipathy R, Wu DY, Yang L. Quantification of the Real Plasmonic Field Transverse Distribution in a Nanocavity Using the Vibrational Stark Effect. J Phys Chem Lett 2023; 14:1708-1713. [PMID: 36757268 DOI: 10.1021/acs.jpclett.2c03818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Quantifying the real plasmonic field strength experimentally has been long pursued in expanding the applications related to plasmonic enhancement. However, it is still an enormous challenge to determine the inhomogeneous plasmonic field distribution. Here, self-assembled monolayers (SAMs) of 4-mercaptobenzonitrile (MBN) are sandwiched as a gap spacer in a nanoparticle-on-mirror (NPoM) structure, effectively forming ultrahigh field enhancement to observe Stark shifts of the chemical bond. Transverse position-dependent Stark shifts of ν(C═C) and ν(C≡N) in the individual nanocavity measured by surface-enhanced Raman scattering (SERS) experiment combined with the Stark tuning rate by density functional theory (DFT) simulation accurately revealed the inhomogeneous plasmonic field transverse distribution and quantified the transverse plasmonic field strength up to ∼1.9 × 109 V/m, which matches the value predicted by finite element method (FEM) simulation. This work deepens the insight into plasmon-based technologies and will coordinate high-resolution techniques such as tip-enhanced Raman spectroscopy (TESR) to reveal the real plasmonic field distribution.
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Affiliation(s)
- Siyu Chen
- Institute of Health and Medical Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, Anhui, China
- University of Science & Technology of China, Hefei 230026, Anhui, China
| | - Yuan-Hui Xiao
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian, China
| | - Miao Qin
- Institute of Health and Medical Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, Anhui, China
| | - Guoliang Zhou
- Institute of Health and Medical Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, Anhui, China
- University of Science & Technology of China, Hefei 230026, Anhui, China
| | - Ronglu Dong
- Institute of Health and Medical Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, Anhui, China
| | - Rajkumar Devasenathipathy
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian, China
| | - De-Yin Wu
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian, China
| | - Liangbao Yang
- Institute of Health and Medical Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, Anhui, China
- University of Science & Technology of China, Hefei 230026, Anhui, China
- Department of Pharmacy, Hefei Cancer Hospital, Chinese Academy of Sciences, Hefei 230031, Anhui, China
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54
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Aldossary A, Gimferrer M, Mao Y, Hao H, Das AK, Salvador P, Head-Gordon T, Head-Gordon M. Force Decomposition Analysis: A Method to Decompose Intermolecular Forces into Physically Relevant Component Contributions. J Phys Chem A 2023; 127:1760-1774. [PMID: 36753558 DOI: 10.1021/acs.jpca.2c08061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
Computational quantum chemistry can be more than just numerical experiments when methods are specifically adapted to investigate chemical concepts. One important example is the development of energy decomposition analysis (EDA) to reveal the physical driving forces behind intermolecular interactions. In EDA, typically the interaction energy from a good-quality density functional theory (DFT) calculation is decomposed into multiple additive components that unveil permanent and induced electrostatics, Pauli repulsion, dispersion, and charge-transfer contributions to noncovalent interactions. Herein, we formulate, implement, and investigate decomposing the forces associated with intermolecular interactions into the same components. The resulting force decomposition analysis (FDA) is potentially useful as a complement to the EDA to understand chemistry, while also providing far more information than an EDA for data analysis purposes such as training physics-based force fields. We apply the FDA based on absolutely localized molecular orbitals (ALMOs) to analyze interactions of water with sodium and chloride ions as well as in the water dimer. We also analyze the forces responsible for geometric changes in carbon dioxide upon adsorption onto (and activation by) gold and silver anions. We also investigate how the force components of an EDA-based force field for water clusters, namely MB-UCB, compare to those from force decomposition analysis.
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Affiliation(s)
- Abdulrahman Aldossary
- Pitzer Center for Theoretical Chemistry, Department of Chemistry, University of California, Berkeley California 94720, United States
| | - Martí Gimferrer
- Institut de Química Computacional i Catàlsi and Departament de Química, Universitat de Girona, 17003 Girona, Catalonia Spain
| | - Yuezhi Mao
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, California 92182, United States
| | - Hongxia Hao
- Pitzer Center for Theoretical Chemistry, Department of Chemistry, University of California, Berkeley California 94720, United States
| | - Akshaya K Das
- Pitzer Center for Theoretical Chemistry, Department of Chemistry, University of California, Berkeley California 94720, United States
| | - Pedro Salvador
- Institut de Química Computacional i Catàlsi and Departament de Química, Universitat de Girona, 17003 Girona, Catalonia Spain
| | - Teresa Head-Gordon
- Pitzer Center for Theoretical Chemistry, Department of Chemistry, University of California, Berkeley California 94720, United States
| | - Martin Head-Gordon
- Pitzer Center for Theoretical Chemistry, Department of Chemistry, University of California, Berkeley California 94720, United States
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55
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Islam A, Kikuchi Y, Iimori T. Electroabsorption and Stark Fluorescence Spectroscopies of Thioflavin T. J Phys Chem A 2023; 127:1436-1444. [PMID: 36740807 DOI: 10.1021/acs.jpca.2c07794] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Thioflavin T (ThT) is a typical fluorescent marker for detecting the formation of amyloid fibrils, because its fluorescence intensity increases by more than 2 orders of magnitude upon complexation with the fibrils. Strong electrostatic fields on protein surfaces are known to be a significant factor in chemical reactions and biological functions. Therefore, ThT bound to amyloid fibrils must experience strong electric fields. This study employed electroabsorption and Stark fluorescence spectroscopies to clarify the effects of external electric fields on the photophysics of ThT. The absorption spectrum shows two bands ascribed to locally excited (LE) and charge transfer (CT) states. Coupling between the LE and CT states is enhanced in the presence of an external electric field, resulting in fluorescence quenching. The electric field strength of the amyloid fibril surface was inferred from the fluorescence quenching efficiency of ThT.
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Affiliation(s)
- Ahatashamul Islam
- Department of Sciences and Informatics, Muroran Institute of Technology, Mizumoto-cho 27-1, Muroran, Hokkaido050-8585, Japan
| | - Yudai Kikuchi
- Department of Sciences and Informatics, Muroran Institute of Technology, Mizumoto-cho 27-1, Muroran, Hokkaido050-8585, Japan
| | - Toshifumi Iimori
- Department of Sciences and Informatics, Muroran Institute of Technology, Mizumoto-cho 27-1, Muroran, Hokkaido050-8585, Japan
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56
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Wang D, Li W, Dong X, Li H, Hu L. TFRegNCI: Interpretable Noncovalent Interaction Correction Multimodal Based on Transformer Encoder Fusion. J Chem Inf Model 2023; 63:782-793. [PMID: 36652718 DOI: 10.1021/acs.jcim.2c01283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The interpretability is an important issue for end-to-end learning models. Motivated by computer vision algorithms, an interpretable noncovalent interaction (NCI) correction multimodal (TFRegNCI) is proposed for NCI prediction. TFRegNCI is based on RegNet feature extraction and a transformer encoder fusion strategy. RegNet is a network design paradigm that mainly focuses on local features. Meanwhile, the Vision Transformer is also leveraged for feature extraction, because it can capture global features better than RegNet while lowering the computational cost. Using a transformer encoder as the fusion strategy rather than multilayer perceptron can enhance model performance, due to its emphasis on important features with less parameters. Therefore, the proposed TFRegNCI achieved high accurate prediction (mean absolute error of ∼0.1 kcal/mol) comparing with the coupled cluster single double (triple) (CCSD(T)) benchmark. To further improve the model efficiency, TFRegNCI applies two-dimensional (2D) inputs transformed from three-dimensional (3D) electron density cubes, which saves time (30%), while the model accuracy remains. To improve model interpretability, a visualization module, Gradient-weighted Regression Activation Mapping (Grad-RAM) has been embedded. Grad-RAM is promoted from the classification algorithm, Gradient-weighted Class Activation Mapping, to perform feature visualization for the regression task. With Grad-RAM, the visual location map for features in deep learning models can be displayed. The feature map visualizations suggest that the 2D model has the similar performance as the 3D model, because of equally effective feature extractions from electron density. Moreover, the valid feature region on the location map by the 3D model is consistent with the NCIPLOT NCI isosurface. It is confirmed that the model does extract significant features related to the NCI interaction. The interpretable analyses are carried out through molecular orbital contribution on effective features. Thereby, the proposed model is likely to be a promising tool to reveal some essential information on NCIs, with regard to the level of electronic theory.
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Affiliation(s)
- Donghan Wang
- School of Information Science and Technology, Northeast Normal University, Changchun130117, China
| | - Wenze Li
- College of Computer and Information Engineering, Henan Normal University, Henan, Xinxiang453007, China
| | - Xu Dong
- School of Information Science and Technology, Northeast Normal University, Changchun130117, China
| | - Hongzhi Li
- School of Information Science and Technology, Northeast Normal University, Changchun130117, China
| | - LiHong Hu
- School of Information Science and Technology, Northeast Normal University, Changchun130117, China
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57
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Fica-Contreras SM, Charnay AP, Pan J, Fayer MD. Rethinking Vibrational Stark Spectroscopy: Peak Shifts, Line Widths, and the Role of Non-Stark Solvent Coupling. J Phys Chem B 2023; 127:717-731. [PMID: 36629314 DOI: 10.1021/acs.jpcb.2c06071] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
A vibration's transition frequency is partly determined by the first-order Stark effect, which accounts for the electric field experienced by the mode. Using ultrafast infrared pump-probe and FT-IR spectroscopies, we characterized both the 0 → 1 and 1 → 2 vibrational transitions' field-dependent peak positions and line widths of the CN stretching mode of benzonitrile (BZN) and phenyl selenocyanate (PhSeCN) in ten solvents. We present a theoretical model that decomposes the observed line width into a field-dependent Stark contribution and a field-independent non-Stark solvent coupling contribution (NSC). The model demonstrates that the field-dependent peak position is independent of the line width, even when the NSC dominates the latter. Experiments show that when the Stark tuning rate is large compared to the NSC (PhSeCN), the line width has a field dependence, albeit with major NSC-induced excursions from linearity. When the Stark tuning rate is small relative to the NSC (BZN), the line width is field-independent. BZN's line widths are substantially larger for the 1 → 2 transition, indicating a 1 → 2 transition enhancement of the NSC. Additionally, we examine, theoretically and experimentally, the difference in the 0 → 1 and 1 → 2 transitions' Stark tuning rates. Second-order perturbation theory combined with density functional theory explain the difference and show that the 1 → 2 transition's Stark tuning rate is ∼10% larger. The Stark tuning rate of PhSeCN is larger than BZN's for both transitions, consistent with the theoretical calculations. This study provides new insights into vibrational line shape components and a more general understanding of the vibrational response to external electric fields.
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Affiliation(s)
| | - Aaron P Charnay
- Department of Chemistry, Stanford University, Stanford, California94305, United States
| | - Junkun Pan
- Department of Chemistry, Stanford University, Stanford, California94305, United States
| | - Michael D Fayer
- Department of Chemistry, Stanford University, Stanford, California94305, United States
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58
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Yang Y, Feng RR, Gai F. 4-Cyanotryptophan as a Sensitive Fluorescence Probe of Local Electric Field of Proteins. J Phys Chem B 2023; 127:514-519. [PMID: 36598839 DOI: 10.1021/acs.jpcb.2c07605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Electrostatic interactions are key determinants of protein structure, dynamics, and function. Since protein electrostatics are nonuniform, assessment of the internal electric fields (EFs) of proteins requires spatial resolution at the amino acid residue level. In this regard, vibrational Stark spectroscopy, in conjunction with various unnatural amino acid-based vibrational probes, has become a common method for site-specific interrogation of protein EFs. However, application of this method is often limited to proteins with relatively high solubility, due to the intrinsically low oscillator strength of vibrational transitions. Therefore, it would be useful to develop an alternative method that can overcome this limitation. To this end, we show that, using solvatochromic study and molecular dynamics simulations, the frequency of maximum emission intensity of the fluorophore of 4-cyanotryptophan (4CN-Trp), 3-methyl-1H-indole-4-carbonitrile, exhibits a linear dependence on the local EF. Since the absorption and emission spectra of 4CN-Trp are easily distinguishable from those of naturally occurring aromatic amino acids, we believe that this linear relationship provides an easier and more sensitive means to determine the local EF of proteins.
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Affiliation(s)
- Yuyao Yang
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Ran-Ran Feng
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Feng Gai
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
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59
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Martins-Costa MTC, Ruiz-López MF. Electrostatics and Chemical Reactivity at the Air-Water Interface. J Am Chem Soc 2023; 145:1400-1406. [PMID: 36622259 DOI: 10.1021/jacs.2c12089] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
It has been recently discovered that chemical reactions at aqueous interfaces can be orders of magnitude faster compared to conventional bulk phase reactions, but despite its wide-ranging implications, which extend from atmospheric to synthetic chemistry or technological applications, the phenomenon is still incompletely understood. The role of strong electric fields due to space asymmetry and the accumulation of ions at the interface has been claimed as a possible cause from some experiments, but the reorganization of the solvent around the reactive system should provide even greater additional electrostatic contributions that have not yet been analyzed. In this study, with the help of first-principles molecular dynamics simulations, we go deeper into this issue by a careful assessment of solvation electrostatics at the air-water interface. Our simulations confirm that electrostatic forces can indeed be a key factor in rate acceleration compared to bulk solution. Remarkably, the study reveals that the effect cannot simply be attributed to the magnitude of the local electric field and that the fluctuations of the full electrostatic potential resulting from unique dynamical behavior of the solvation shells at the interface must be accounted for. This finding paves the way for future applications of the phenomenon in organic synthesis, especially for charge transfer or redox reactions in thin films and microdroplets.
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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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60
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Romei M, von Krusenstiern EV, Ridings ST, King RN, Fortier JC, McKeon CA, Nichols KM, Charkoudian LK, Londergan CH. Frequency Changes in Terminal Alkynes Provide Strong, Sensitive, and Solvatochromic Raman Probes of Biochemical Environments. J Phys Chem B 2023; 127:85-94. [PMID: 36538691 PMCID: PMC9841980 DOI: 10.1021/acs.jpcb.2c06176] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 11/19/2022] [Indexed: 12/24/2022]
Abstract
The C≡C stretching frequencies of terminal alkynes appear in the "clear" window of vibrational spectra, so they are attractive and increasingly popular as site-specific probes in complicated biological systems like proteins, cells, and tissues. In this work, we collected infrared (IR) absorption and Raman scattering spectra of model compounds, artificial amino acids, and model proteins that contain terminal alkyne groups, and we used our results to draw conclusions about the signal strength and sensitivity to the local environment of both aliphatic and aromatic terminal alkyne C≡C stretching bands. While the IR bands of alkynyl model compounds displayed surprisingly broad solvatochromism, their absorptions were weak enough that alkynes can be ruled out as effective IR probes. The same solvatochromism was observed in model compounds' Raman spectra, and comparisons to published empirical solvent scales (including a linear regression against four meta-aggregated solvent parameters) suggested that the alkyne C≡C stretching frequency mainly reports on local electronic interactions (i.e., short-range electron donor-acceptor interactions) with solvent molecules and neighboring functional groups. The strong solvatochromism observed here for alkyne stretching bands introduces an important consideration for Raman imaging studies based on these signals. Raman signals for alkynes (especially those that are π-conjugated) can be exceptionally strong and should permit alkynyl Raman signals to function as probes at very low concentrations, as compared to other widely used vibrational probe groups like azides and nitriles. We incorporated homopropargyl glycine into a transmembrane helical peptide via peptide synthesis, and we installed p-ethynylphenylalanine into the interior of the Escherichia coli fatty acid acyl carrier protein using a genetic code expansion technique. The Raman spectra from each of these test systems indicate that alkynyl C≡C bands can act as effective and unique probes of their local biomolecular environments. We provide guidance for the best possible future uses of alkynes as solvatochromic Raman probes, and while empirical explanations of the alkyne solvatochromism are offered, open questions about its physical basis are enunciated.
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Affiliation(s)
- Matthew
G. Romei
- Department of Chemistry, Haverford College, 370 Lancaster Avenue, Haverford, Pennsylvania 19041-1392, United States
| | - Eliana V. von Krusenstiern
- Department of Chemistry, Haverford College, 370 Lancaster Avenue, Haverford, Pennsylvania 19041-1392, United States
| | - Stephen T. Ridings
- Department of Chemistry, Haverford College, 370 Lancaster Avenue, Haverford, Pennsylvania 19041-1392, United States
| | - Renee N. King
- Department of Chemistry, Haverford College, 370 Lancaster Avenue, Haverford, Pennsylvania 19041-1392, United States
| | - Julia C. Fortier
- Department of Chemistry, Haverford College, 370 Lancaster Avenue, Haverford, Pennsylvania 19041-1392, United States
| | - Caroline A. McKeon
- Department of Chemistry, Haverford College, 370 Lancaster Avenue, Haverford, Pennsylvania 19041-1392, United States
| | - Krysta M. Nichols
- Department of Chemistry, Haverford College, 370 Lancaster Avenue, Haverford, Pennsylvania 19041-1392, United States
| | - Louise K. Charkoudian
- Department of Chemistry, Haverford College, 370 Lancaster Avenue, Haverford, Pennsylvania 19041-1392, United States
| | - Casey H. Londergan
- Department of Chemistry, Haverford College, 370 Lancaster Avenue, Haverford, Pennsylvania 19041-1392, United States
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61
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Chakrabarty S, Ghosh A. Inconsistent hydrogen bond-mediated vibrational coupling of amide I. RSC Adv 2023; 13:1295-1300. [PMID: 36686902 PMCID: PMC9814034 DOI: 10.1039/d2ra07177k] [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: 11/12/2022] [Accepted: 12/16/2022] [Indexed: 01/06/2023] Open
Abstract
Using infrared spectroscopy and density functional theory (DFT) calculations, we scrutinized an amide (dimethylformamide) as a "model" compound to interpret the interactions of amide 1 with different phenol derivatives (para-chlorophenol (PCP) and para-cresol (CP)) as "model guest molecules". We established the involvement of amide I in vibrational coupling with symmetric and asymmetric C[double bond, length as m-dash]C modes of different phenolic derivatives and how their coupling was dependent upon different guest aromatic phenolic compounds. Interestingly, substitution of phenol perturbed the pattern of vibrational coupling with amide I. The symmetric and asymmetric C[double bond, length as m-dash]C modes of PC were coupled significantly with amide 1. For PCP, the symmetric C[double bond, length as m-dash]C mode coupled significantly, but the asymmetric mode coupled negligibly, with amide I. Here, we reveal the nature of vibrational coupling based on the structure of a guest molecule hydrogen-bonded with amide I. Our conclusions could be valuable for depiction of the unusual dynamics of coupled amide-I modes as well as the dependency of vibrational coupling on altered factors.
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Affiliation(s)
- Suranjana Chakrabarty
- a, Department of Condensed Matter of Physics and Materials Sciences, S. N. Bose National Centre for Basic SciencesJD Block, Sector-III, Salt Lake CityKolkata – 700 106India
| | - Anup Ghosh
- a, Department of Condensed Matter of Physics and Materials Sciences, S. N. Bose National Centre for Basic SciencesJD Block, Sector-III, Salt Lake CityKolkata – 700 106India
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62
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Haldar T, Chatterjee S, Alam MN, Maity P, Bagchi S. Blue Fluorescence of Cyano-tryptophan Predicts Local Electrostatics and Hydrogen Bonding in Biomolecules. J Phys Chem B 2022; 126:10732-10740. [PMID: 36511763 DOI: 10.1021/acs.jpcb.2c05848] [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
Cyano-tryptophan is an unnatural fluorescent amino acid that emits in the visible region. Along with the structural similarity with tryptophan, the unique photophysical properties of this fluorophore make it an ideal probe for biophysical research. Herein, combining fluorescence spectroscopy, infrared spectroscopy, and molecular dynamics simulations, we show that the cyano-tryptophan's emission energy quantifies the underlying bond-specific noncovalent interactions in terms of the electric field. We further report the use of fluorophore's emission energy to predict its hydrogen bond characteristics. We demonstrate that combining experiments with molecular dynamics simulations can provide the hydrogen bonding status of the nitrile moiety. In addition, we report a method to differentiate between aqueous and nonaqueous hydrogen-bonding partners. Using a phenomenological approach, we demonstrate that the presence of the cyano-indole moiety is responsible for the distinct correlations between the fluorophore's emission and the electrostatic forces on the nitrile bond. As indole is a privileged scaffold for both native amino acids and nucleobases, cyano-indoles will have many multifaceted applications.
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Affiliation(s)
- Tapas Haldar
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Pune411008, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad201002, India
| | - Srijan Chatterjee
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Pune411008, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad201002, India
| | - Md Nirshad Alam
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Pune411008, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad201002, India
| | - Pradip Maity
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Pune411008, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad201002, India
| | - Sayan Bagchi
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Pune411008, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad201002, India
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63
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Brunner syndrome caused by point mutation explained by multiscale simulation of enzyme reaction. Sci Rep 2022; 12:21889. [PMID: 36536002 PMCID: PMC9763434 DOI: 10.1038/s41598-022-26296-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022] Open
Abstract
Brunner syndrome is a disorder characterized by intellectual disability and impulsive, aggressive behavior associated with deficient function of the monoamine oxidase A (MAO-A) enzyme. These symptoms (along with particularly high serotonin levels) have been reported in patients with two missense variants in MAO-A (p.R45W and p.E446K). Herein, we report molecular simulations of the rate-limiting step of MAO-A-catalyzed serotonin degradation for these variants. We found that the R45W mutation causes a 6000-fold slowdown of enzymatic function, whereas the E446K mutation causes a 450-fold reduction of serotonin degradation rate, both of which are practically equivalent to a gene knockout. In addition, we thoroughly compared the influence of enzyme electrostatics on the catalytic function of both the wild type MAO-A and the p.R45W variant relative to the wild type enzyme, revealing that the mutation represents a significant electrostatic perturbation that contributes to the barrier increase. Understanding genetic disorders is closely linked to understanding the associated chemical mechanisms, and our research represents a novel attempt to bridge the gap between clinical genetics and the underlying chemical physics.
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64
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Dubey KD, Stuyver T, Shaik S. Local Electric Fields: From Enzyme Catalysis to Synthetic Catalyst Design. J Phys Chem B 2022; 126:10285-10294. [PMID: 36469939 DOI: 10.1021/acs.jpcb.2c06422] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
This Mini-Review Article outlines recent advances in the study of local electric field (LEF) governed enzyme catalysis and the application of the LEF principle in synthetic catalyst design. We start by discussing the electrostatics principles that drive enzyme catalysis, and its experimental verifications through vibrational Stark spectroscopy. Subsequently, we describe aspects of LEFs other than catalysis, i.e., induction of mechanistic crossovers, among others. Here, we focus on the early work done using computational tools, along with some recent contributions. Following an in-depth discussion of the role of LEFs in enzyme catalysis, we then highlight some recent works on designed local electric fields (D-LEF) and their applications in organic synthesis. Subsequently, we turn to D-LEFs in synthetic enzymes and supramolecular systems (cf. the work by the Head-Gordon group). We end by discussing some of the software packages that have been developed to analyze local electric fields computationally. Overall, the present Mini-Review Article paints an insightful picture of the current state of the art using LEF in enzyme catalysis and its application for further bioengineering and synthetic organic frameworks in a broad perspective.
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Affiliation(s)
- Kshatresh Dutta Dubey
- Department of Chemistry, School of Natural Sciences, Shiv Nadar Institution of Eminence Delhi-NCR, Gautam Buddha Nagar, Uttar Pradesh201314, India
| | - Thijs Stuyver
- Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts02139, United States
| | - Sason Shaik
- The Hebrew University, Institute of Chemistry, Edmond J. Safra Campus at Givat Ram, Jerusalem, 9190401Israel
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65
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Röckert A, Kullgren J, Hermansson K. Predicting Frequency from the External Chemical Environment: OH Vibrations on Hydrated and Hydroxylated Surfaces. J Chem Theory Comput 2022; 18:7683-7694. [PMID: 36458913 DOI: 10.1021/acs.jctc.2c00135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Robust correlation curves are essential to decipher structural information from IR-vibrational spectra. However, for surface-adsorbed water and hydroxides, few such correlations have been presented in the literature. In this paper, OH vibrational frequencies are correlated against 12 structural descriptors representing the quantum mechanical or geometrical environment, focusing on those external to the vibrating molecule. A nonbiased fitting procedure based on Gaussian process regression (GPR) was used alongside simple analytical functional forms. The training data consist of 217 structurally unique OH groups from 38 water/metal oxide interface systems for MgO, CaO and CeO2, all optimized at the DFT level, and the fully anharmonic and uncoupled OH vibrational signatures were calculated. Among our results, we find the following: (i) The intermolecular R(H···O) hydrogen bond distance is particularly strong, indicating the primary cause of the frequency shift. (ii) Similarly, the electric field along the H-bond vector is also a good descriptor. (iii) Highly detailed machine learning descriptors (ACSF, SOAP) are less intuitive but were found to be more capable descriptors. (iv) Combinations of geometric and QM descriptors give the best predictions, supplying complementary information.
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Affiliation(s)
- Andreas Röckert
- Department of Chemistry, Ångström Laboratory, Uppsala University, Uppsala751 21, Sweden
| | - Jolla Kullgren
- Department of Chemistry, Ångström Laboratory, Uppsala University, Uppsala751 21, Sweden
| | - Kersti Hermansson
- Department of Chemistry, Ångström Laboratory, Uppsala University, Uppsala751 21, Sweden
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66
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Parker GL, Van Lommel R, Roig N, Alonso M, Chaplin AB. Modulation of Metal Carbonyl Stretching Frequencies in the Second Coordination Sphere through the Internal Stark Effect. Chemistry 2022; 28:e202202283. [PMID: 36082961 PMCID: PMC10092048 DOI: 10.1002/chem.202202283] [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: 07/21/2022] [Indexed: 12/14/2022]
Abstract
Spectroscopic and computational examination of a homologous series of rhodium(I) pybox carbonyl complexes has revealed a correlation between the conformation of the flanking aryl-substituted oxazoline donors and the carbonyl stretching frequency. This relationship is also observed experimentally for octahedral rhodium(III) and ruthenium(II) variants and cannot be explained through the classical, Dewar-Chatt-Duncanson, interpretation of metal-carbonyl bonding. Instead, these findings are reconciled by local changes in the magnitude of the electric field that is projected along the metal-carbonyl vector: the internal Stark effect.
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Affiliation(s)
- Gemma L Parker
- Department of Chemistry, University of Warwick, Gibbet Hill Road, CV4 7AL, Coventry, UK
| | - Ruben Van Lommel
- Eenheid Algemene Chemie (ALGC), Vrije Universiteit Brussel (VUB), 1050, Brussels, Belgium.,Molecular Design and Synthesis, Department of Chemistry, KU Leuven, 3001, Leuven, Belgium
| | - Nil Roig
- Department of Chemistry, University of Warwick, Gibbet Hill Road, CV4 7AL, Coventry, UK.,Eenheid Algemene Chemie (ALGC), Vrije Universiteit Brussel (VUB), 1050, Brussels, Belgium
| | - Mercedes Alonso
- Eenheid Algemene Chemie (ALGC), Vrije Universiteit Brussel (VUB), 1050, Brussels, Belgium
| | - Adrian B Chaplin
- Department of Chemistry, University of Warwick, Gibbet Hill Road, CV4 7AL, Coventry, UK
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67
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Askelson PG, Meloni SL, Hoffnagle AM, Anna JM. Resolving the Impact of Hydrogen Bonding on the Phylloquinone Cofactor through Two-Dimensional Infrared Spectroscopy. J Phys Chem B 2022; 126:10120-10135. [PMID: 36444999 DOI: 10.1021/acs.jpcb.2c03556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Two-dimensional infrared spectroscopy (2DIR) was applied to phylloquinone (PhQ), an important biological cofactor, to elucidate the impact of hydrogen bonding on the ultrafast dynamics and energetics of the carbonyl stretching modes. 2DIR measurements were performed on PhQ dissolved in hexanol, which served as the hydrogen bonding solvent, and hexane, which served as a non-hydrogen bonding control. Molecular dynamics simulations and quantum chemical calculations were performed to aid in spectral assignment and interpretation. From the position of the peaks in the 2DIR spectra, we extracted the transition frequencies for the fundamental, overtone, and combination bands of hydrogen bonded and non-hydrogen bonded carbonyl groups of PhQ in the 1635-1680 cm-1 region. We find that hydrogen bonding to a single carbonyl group acts to decouple the two carbonyl units of PhQ. Through analysis of the time-resolved 2DIR data, we find that hydrogen bonding leads to faster vibrational relaxation as well as an increase in the inhomogeneous broadening of the carbonyl groups. Overall, this work demonstrates how hydrogen bonding to the carbonyl groups of PhQ presents in the 2DIR spectra, laying the groundwork to use PhQ as a 2DIR probe to characterize the ultrafast fluctuations in the local environment of natural photosynthetic complexes.
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Affiliation(s)
- Phoebe G Askelson
- Department of Chemistry, University of Pennsylvania, 231 South 34 Street, Philadelphia, Pennsylvania19104, United States
| | - Stephen L Meloni
- Department of Chemistry, University of Pennsylvania, 231 South 34 Street, Philadelphia, Pennsylvania19104, United States
| | - Alexander M Hoffnagle
- Department of Chemistry, University of Pennsylvania, 231 South 34 Street, Philadelphia, Pennsylvania19104, United States
| | - Jessica M Anna
- Department of Chemistry, University of Pennsylvania, 231 South 34 Street, Philadelphia, Pennsylvania19104, United States
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68
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Ji Z, Boxer SG. β-Lactamases Evolve against Antibiotics by Acquiring Large Active-Site Electric Fields. J Am Chem Soc 2022; 144:22289-22294. [PMID: 36399691 PMCID: PMC10075085 DOI: 10.1021/jacs.2c10791] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A compound bound covalently to an enzyme active site can act either as a substrate if the covalent linkage is readily broken up by the enzyme or as an inhibitor if the bond dissociates slowly. We tracked the reactivity of such bonds associated with the rise of the resistance to penicillin G (PenG) in protein evolution from penicillin-binding proteins (PBPs) to TEM β-lactamases and with the development of avibactam (Avb) to overcome the resistance. We found that the ester linkage in PBP-PenG is resistant to hydrolysis mainly due to the small electric fields present in the protein active site. Conversely, the same linkage in the descendant TEM-PenG experiences large electric fields that stabilize the more charge-separated transition state and thus lower the free energy barrier to hydrolysis. Specifically, the electric fields were improved from -59 to -140 MV/cm in an ancient evolution dating back billions of years, contributing 5 orders of magnitude rate acceleration. This trend continues today in the nullification of newly developed antibiotic drugs. The fast linkage hydrolysis acquired from evolution is counteracted by the upgrade of PenG to Avb whose linkage escapes from the hydrolysis by returning to a low-field environment. Using the framework of electrostatic catalysis, the electric field, an observable from vibrational spectroscopy, provides a unifying physical metric to understand protein evolution and to guide the design of covalent drugs.
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Affiliation(s)
- Zhe Ji
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Steven G Boxer
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
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69
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Ji Z, Kozuch J, Mathews II, Diercks CS, Shamsudin Y, Schulz MA, Boxer SG. Protein Electric Fields Enable Faster and Longer-Lasting Covalent Inhibition of β-Lactamases. J Am Chem Soc 2022; 144:20947-20954. [PMID: 36324090 PMCID: PMC10066720 DOI: 10.1021/jacs.2c09876] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The widespread design of covalent drugs has focused on crafting reactive groups of proper electrophilicity and positioning toward targeted amino-acid nucleophiles. We found that environmental electric fields projected onto a reactive chemical bond, an overlooked design element, play essential roles in the covalent inhibition of TEM-1 β-lactamase by avibactam. Using the vibrational Stark effect, the magnitudes of the electric fields that are exerted by TEM active sites onto avibactam's reactive C═O were measured and demonstrate an electrostatic gating effect that promotes bond formation yet relatively suppresses the reverse dissociation. These results suggest new principles of covalent drug design and off-target site prediction. Unlike shape and electrostatic complementary which address binding constants, electrostatic catalysis drives reaction rates, essential for covalent inhibition, and deepens our understanding of chemical reactivity, selectivity, and stability in complex systems.
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Affiliation(s)
- Zhe Ji
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Jacek Kozuch
- Department of Physics, Experimental Molecular Biophysics, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin, Germany
- Research Building SupraFAB, Altensteinstreet 23a, 14195 Berlin, Germany
| | - Irimpan I Mathews
- Stanford Synchrotron Radiation Lightsource, Menlo Park, California 94025, United States
| | - Christian S Diercks
- Department of Chemistry, Scripps Research, La Jolla, California 92037, United States
| | - Yasmin Shamsudin
- Department of Chemistry-BMC, Uppsala University, 752 37 Uppsala, Sweden
| | - Mirjam A Schulz
- Department of Physics, Experimental Molecular Biophysics, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin, Germany
- Research Building SupraFAB, Altensteinstreet 23a, 14195 Berlin, Germany
| | - Steven G Boxer
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
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70
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Kraka E, Quintano M, La Force HW, Antonio JJ, Freindorf M. The Local Vibrational Mode Theory and Its Place in the Vibrational Spectroscopy Arena. J Phys Chem A 2022; 126:8781-8798. [DOI: 10.1021/acs.jpca.2c05962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Elfi Kraka
- Computational and Theoretical Chemistry Group (CATCO), Department of Chemistry, Southern Methodist University, 3215 Daniel Ave, Dallas, Texas75275-0314, United States
| | - Mateus Quintano
- Computational and Theoretical Chemistry Group (CATCO), Department of Chemistry, Southern Methodist University, 3215 Daniel Ave, Dallas, Texas75275-0314, United States
| | - Hunter W. La Force
- Computational and Theoretical Chemistry Group (CATCO), Department of Chemistry, Southern Methodist University, 3215 Daniel Ave, Dallas, Texas75275-0314, United States
| | - Juliana J. Antonio
- Computational and Theoretical Chemistry Group (CATCO), Department of Chemistry, Southern Methodist University, 3215 Daniel Ave, Dallas, Texas75275-0314, United States
| | - Marek Freindorf
- Computational and Theoretical Chemistry Group (CATCO), Department of Chemistry, Southern Methodist University, 3215 Daniel Ave, Dallas, Texas75275-0314, United States
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71
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Meyer KAE, Nickson KA, Garand E. The impact of the electric field of metal ions on the vibrations and internal hydrogen bond strength in alkali metal ion di- and triglycine complexes. J Chem Phys 2022; 157:174301. [DOI: 10.1063/5.0117311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Using infrared predissociation spectroscopy of cryogenic ions, we revisit the vibrational spectra of alkali metal ion (Li+, Na+, K+) di- and triglycine complexes. We assign their most stable conformation, which involves metal ion coordination to all C=O groups and an internal NH⋯NH2 hydrogen bond in the peptide backbone. An analysis of the spectral shifts of the OH and C=O stretching vibrations across the different metal ions and peptide chain lengths shows that these are largely caused by the electric field of the metal ion, which varies in strength as a function of the square of the distance. The metal ion–peptide interaction also remotely modulates the strength of internal hydrogen bonding in the peptide backbone via the weakening of the amide C=O bond, resulting in a decrease in internal hydrogen bond strength from Li+ > Na+ > K+.
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Affiliation(s)
- Katharina A. E. Meyer
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave., Madison, Wisconsin 53706, USA
| | - Kathleen A. Nickson
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave., Madison, Wisconsin 53706, USA
| | - Etienne Garand
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave., Madison, Wisconsin 53706, USA
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72
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Yang RY, Jiang WZ, Huo PY. Anisotropic energy absorption from mid-infrared laser pulses in constrained water systems. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.120286] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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73
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Cassone G, Sponer J, Sponer JE, Saija F. Electrofreezing of Liquid Ammonia. J Phys Chem Lett 2022; 13:9889-9894. [PMID: 36255376 PMCID: PMC9619927 DOI: 10.1021/acs.jpclett.2c02576] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 10/13/2022] [Indexed: 05/25/2023]
Abstract
Here we prove that, in addition to temperature and pressure, another important thermodynamic variable permits the exploration of the phase diagram of ammonia: the electric field. By means of (path integral) ab initio molecular dynamics simulations, we predict that, upon applying intense electric fields on ammonia, the electrofreezing phenomenon occurs, leading the liquid toward a novel ferroelectric solid phase. This study proves that electric fields can generally be exploited as the access key to otherwise-unreachable regions in phase diagrams, unveiling the existence of new condensed-phase structures. Furthermore, the reported findings have manifold practical implications, from the safe storage and transportation of ammonia to the understanding of the solid structures this compound forms in planetary contexts.
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Affiliation(s)
- Giuseppe Cassone
- Institute
for Chemical-Physical Processes, National
Research Council of Italy, Viale F. Stagno d’Alcontres 37, 98158 Messina, Italy
| | - Jiri Sponer
- Institute
of Biophysics of the Czech Academy of Sciences, Královopolská 135, 61265 Brno, Czechia
- Regional
Center of Advanced Technologies and Materials, The Czech Advanced
Technology and Research Institute (CATRIN), Palacky University Olomouc, Slechtitelu 27, 77900 Olomouc, Czechia
| | - Judit E. Sponer
- Institute
of Biophysics of the Czech Academy of Sciences, Královopolská 135, 61265 Brno, Czechia
| | - Franz Saija
- Institute
for Chemical-Physical Processes, National
Research Council of Italy, Viale F. Stagno d’Alcontres 37, 98158 Messina, Italy
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74
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Peng W, Yan S, Zhang X, Liao L, Zhang J, Shaik S, Wang B. How Do Preorganized Electric Fields Function in Catalytic Cycles? The Case of the Enzyme Tyrosine Hydroxylase. J Am Chem Soc 2022; 144:20484-20494. [DOI: 10.1021/jacs.2c09263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Wei Peng
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering and Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen University, Xiamen 361005, People Republic of China
| | - Shengheng Yan
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering and Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen University, Xiamen 361005, People Republic of China
| | - Xuan Zhang
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering and Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen University, Xiamen 361005, People Republic of China
| | - Langxing Liao
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering and Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen University, Xiamen 361005, People Republic of China
| | - Jinyan Zhang
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering and Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen University, Xiamen 361005, People Republic of China
| | - Sason Shaik
- Institute of Chemistry, The Hebrew University of Jerusalem, 9190407 Jerusalem, Israel
| | - Binju Wang
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering and Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen University, Xiamen 361005, People Republic of China
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75
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Aranda D, García-González F, Avila Ferrer FJ, López-Tocón I, Soto J, Otero JC. Computational Model for Electrochemical Surface-Enhanced Raman Scattering: Key Role of the Surface Charges and Synergy between Electromagnetic and Charge-Transfer Enhancement Mechanisms. J Chem Theory Comput 2022; 18:6802-6815. [PMID: 36222738 DOI: 10.1021/acs.jctc.2c00633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We present a computational model for electrochemical surface-enhanced Raman scattering (EC-SERS). The surface excess of charge induced by the electrode potential (Vel) was introduced by applying an external electric field to a set of clusters [Agn]q with (n, q) of (19, ±1) or (20, 0) on which a molecule adsorbs. Using DFT/TD-DFT calculations, these metal-molecule complexes were classified by the adsorbate partial charge, and the main Vel-dependent properties were simultaneously studied with the aid of vibronic resonance Raman computations, namely, changes on the vibrational wavenumbers, relative intensities, and enhancement factors (EFs) for all SERS mechanisms: chemical or nonresonant, and resonance Raman with bright states of the adsorbate, charge-transfer (CT) states, and plasmon-like excitations on the metal cluster. We selected two molecules to test our model, pyridine, for which Vel has a remarkable effect, and 9,10-bis((E)-2-(pyridin-4-yl)vinyl)anthracene, which is almost insensitive to the applied bias. The results nicely reproduced most of the experimental observations, while the limitations of our approach were critically evaluated. We detected that accounting explicitly for the surface charges is key for EC-SERS models and that the highest calculated EFs, up to 107 to 108, are obtained by interstate coupling of bright local excitations of the metal cluster and CT states. These results highlight the importance of nonadiabatic effects in SERS and the capabilities of EC-SERS as a technique with potential to study excited-state coupling by tuning the CT and plasmon-like states by manipulating Vel.
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Affiliation(s)
- Daniel Aranda
- Instituto de Ciencia Molecular (ICMol), Universidad de Valencia, Catedrático J. Beltrán 2, 46980Paterna, Valencia, Spain.,Andalucía Tech, Facultad de Ciencias, Departamento de Química Física, Universidad de Málaga, 29071Málaga, Spain
| | - Francisco García-González
- Andalucía Tech, Facultad de Ciencias, Departamento de Química Física, Universidad de Málaga, 29071Málaga, Spain
| | - Francisco José Avila Ferrer
- Andalucía Tech, Facultad de Ciencias, Departamento de Química Física, Universidad de Málaga, 29071Málaga, Spain
| | - Isabel López-Tocón
- Andalucía Tech, Facultad de Ciencias, Departamento de Química Física, Universidad de Málaga, 29071Málaga, Spain
| | - Juan Soto
- Andalucía Tech, Facultad de Ciencias, Departamento de Química Física, Universidad de Málaga, 29071Málaga, Spain
| | - Juan Carlos Otero
- Andalucía Tech, Facultad de Ciencias, Departamento de Química Física, Universidad de Málaga, 29071Málaga, Spain
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76
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Utesch T, Staffa J, Katz S, Yao G, Kozuch J, Hildebrandt P. Potential Distribution across Model Membranes. J Phys Chem B 2022; 126:7664-7675. [PMID: 36137267 DOI: 10.1021/acs.jpcb.2c05372] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Membrane models assembled on electrodes are widely used tools to study potential-dependent molecular processes at or in membranes. However, the relationship between the electrode potential and the potential across the membrane is not known. Here we studied lipid bilayers immobilized on mixed self-assembled monolayers (SAM) on Au electrodes. The mixed SAM was composed of thiol derivatives of different chain lengths such that between the islands of the short one, mercaptobenzonitrile (MBN), and the tethered lipid bilayer an aqueous compartment was formed. The nitrile function of MBN, which served as a reporter group for the vibrational Stark effect (VSE), was probed by surface-enhanced infrared absorption spectroscopy to determine the local electric field as a function of the electrode potential for pure MBN, mixed SAM, and the bilayer system. In parallel, we calculated electric fields at the VSE probe by molecular dynamics (MD) simulations for different charge densities on the metal, thereby mimicking electrode potential changes. The agreement with the experiments was very good for the calculations of the pure MBN SAM and only slightly worse for the mixed SAM. The comparison with the experiments also guided the design of the bilayer system in the MD setups, which were selected to calculate the electrode potential dependence of the transmembrane potential, a quantity that is not directly accessible by the experiments. The results agree very well with estimates in previous studies and thus demonstrate that the present combined experimental-theoretical approach is a promising tool for describing potential-dependent processes at biomimetic interfaces.
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Affiliation(s)
- Tillmann Utesch
- Leibniz-Institut für Molekulare Pharmakologie (FMP), Robert-Rössle-Strasse 10, D-13125 Berlin, Germany
| | - Jana Staffa
- Institut für Chemie, Technische Universität Berlin, Sekr. PC14, Straße des 17. Juni 135, D-10623 Berlin, Germany
| | - Sagie Katz
- Institut für Chemie, Technische Universität Berlin, Sekr. PC14, Straße des 17. Juni 135, D-10623 Berlin, Germany
| | - Guiyang Yao
- Institut für Chemie, Technische Universität Berlin, Sekr. PC14, Straße des 17. Juni 135, D-10623 Berlin, Germany
| | - Jacek Kozuch
- Fachbereich Physik, Experimentelle Molekulare Biophysik, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin, Germany.,Forschungsbau SupraFAB, Altensteinstr. 23a, D-14195 Berlin, Germany
| | - Peter Hildebrandt
- Institut für Chemie, Technische Universität Berlin, Sekr. PC14, Straße des 17. Juni 135, D-10623 Berlin, Germany
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77
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Electric fields control water-gated proton transfer in cytochrome c oxidase. Proc Natl Acad Sci U S A 2022; 119:e2207761119. [PMID: 36095184 PMCID: PMC9499568 DOI: 10.1073/pnas.2207761119] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Aerobic life is powered by membrane-bound enzymes that catalyze the transfer of electrons to oxygen and protons across a biological membrane. Cytochrome c oxidase (CcO) functions as a terminal electron acceptor in mitochondrial and bacterial respiratory chains, driving cellular respiration and transducing the free energy from O2 reduction into proton pumping. Here we show that CcO creates orientated electric fields around a nonpolar cavity next to the active site, establishing a molecular switch that directs the protons along distinct pathways. By combining large-scale quantum chemical density functional theory (DFT) calculations with hybrid quantum mechanics/molecular mechanics (QM/MM) simulations and atomistic molecular dynamics (MD) explorations, we find that reduction of the electron donor, heme a, leads to dissociation of an arginine (Arg438)-heme a3 D-propionate ion-pair. This ion-pair dissociation creates a strong electric field of up to 1 V Å-1 along a water-mediated proton array leading to a transient proton loading site (PLS) near the active site. Protonation of the PLS triggers the reduction of the active site, which in turn aligns the electric field vectors along a second, "chemical," proton pathway. We find a linear energy relationship of the proton transfer barrier with the electric field strength that explains the effectivity of the gating process. Our mechanism shows distinct similarities to principles also found in other energy-converting enzymes, suggesting that orientated electric fields generally control enzyme catalysis.
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78
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Mueller N, Arul R, Jakob LA, Blunt MO, Földes T, Rosta E, Baumberg JJ. Collective Mid-Infrared Vibrations in Surface-Enhanced Raman Scattering. NANO LETTERS 2022; 22:7254-7260. [PMID: 36037474 PMCID: PMC9479150 DOI: 10.1021/acs.nanolett.2c02806] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 08/22/2022] [Indexed: 06/15/2023]
Abstract
Surface-enhanced Raman scattering (SERS) is typically assumed to occur at individual molecules neglecting intermolecular vibrational coupling. Here, we show instead how collective vibrations from infrared (IR) coupled dipoles are seen in SERS from molecular monolayers. Mixing IR-active molecules with IR-inactive spacer molecules controls the intermolecular separation. Intermolecular coupling leads to vibrational frequency upshifts up to 8 cm-1, tuning with the mixing fraction and IR dipole strength, in excellent agreement with microscopic models and density functional theory. These cooperative frequency shifts can be used as a ruler to measure intermolecular distance and disorder with angstrom resolution. We demonstrate this for photochemical reactions of 4-nitrothiophenol, which depletes the number of neighboring IR-active molecules and breaks the collective vibration, enabling direct tracking of the reaction. Collective molecular vibrations reshape SERS spectra and need to be considered in the analysis of vibrational spectra throughout analytical chemistry and sensing.
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Affiliation(s)
- Niclas
S. Mueller
- NanoPhotonics
Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Rakesh Arul
- NanoPhotonics
Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Lukas A. Jakob
- NanoPhotonics
Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Matthew Oliver Blunt
- Department
of Physics and Astronomy, University College
London, London WC1E 6BT, United Kingdom
| | - Tamás Földes
- Department
of Physics and Astronomy, University College
London, London WC1E 6BT, United Kingdom
| | - Edina Rosta
- Department
of Physics and Astronomy, University College
London, London WC1E 6BT, United Kingdom
| | - Jeremy J. Baumberg
- NanoPhotonics
Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom
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79
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Unconventional interfacial water structure of highly concentrated aqueous electrolytes at negative electrode polarizations. Nat Commun 2022; 13:5330. [PMID: 36088353 PMCID: PMC9464189 DOI: 10.1038/s41467-022-33129-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 09/02/2022] [Indexed: 11/09/2022] Open
Abstract
AbstractWater-in-salt electrolytes are an appealing option for future electrochemical energy storage devices due to their safety and low toxicity. However, the physicochemical interactions occurring at the interface between the electrode and the water-in-salt electrolyte are not yet fully understood. Here, via in situ Raman spectroscopy and molecular dynamics simulations, we investigate the electrical double-layer structure occurring at the interface between a water-in-salt electrolyte and an Au(111) electrode. We demonstrate that most interfacial water molecules are bound with lithium ions and have zero, one, or two hydrogen bonds to feature three hydroxyl stretching bands. Moreover, the accumulation of lithium ions on the electrode surface at large negative polarizations reduces the interfacial field to induce an unusual “hydrogen-up” structure of interfacial water and blue shift of the hydroxyl stretching frequencies. These physicochemical behaviours are quantitatively different from aqueous electrolyte solutions with lower concentrations. This atomistic understanding of the double-layer structure provides key insights for designing future aqueous electrolytes for electrochemical energy storage devices.
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80
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Cohn B, Sufrin S, Basu A, Chuntonov L. Vibrational Polaritons in Disordered Molecular Ensembles. J Phys Chem Lett 2022; 13:8369-8375. [PMID: 36043884 PMCID: PMC9465717 DOI: 10.1021/acs.jpclett.2c02341] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 08/26/2022] [Indexed: 06/12/2023]
Abstract
Disorder is an intrinsic attribute of any realistic molecular system. It is known to lead to localization, which hampers efficient transport. It was recently proposed that in molecular ensembles strongly coupled to photonic cavities, moderate disorder leads to delocalization and increases of the transport and chemical reaction rates. Vibrational polaritons involve molecular vibrations hybridized with an infrared cavity. When the coupling strength largely exceeds the molecular inhomogeneity, polaritons are unaffected by disorder. However, in many experiments, such a homogeneous limit does not apply. We investigated vibrational polaritons involving molecular ensembles with systematically modified disorder. Counterintuitively, moderate disorder leads to an increase in Rabi splitting and the modification of the polariton bandwidths. Experimental spectroscopic data agree with a Tavis-Cummings-like model that suggests enhanced delocalization of the reservoir states occurs via the admixture of the cavity mode. Our results provide new insights into the paradigm of disorder-induced cavity-assisted delocalization in molecular polaritons.
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Affiliation(s)
- Bar Cohn
- Schulich
Faculty of Chemistry, Solid State Institute, Faculty of Mechanical Engineering, Technion−Israel Institute of Technology, Haifa 3200003, Israel
| | - Shmuel Sufrin
- Schulich
Faculty of Chemistry, Solid State Institute, Faculty of Mechanical Engineering, Technion−Israel Institute of Technology, Haifa 3200003, Israel
| | - Arghyadeep Basu
- Schulich
Faculty of Chemistry, Solid State Institute, Faculty of Mechanical Engineering, Technion−Israel Institute of Technology, Haifa 3200003, Israel
| | - Lev Chuntonov
- Schulich
Faculty of Chemistry, Solid State Institute, Faculty of Mechanical Engineering, Technion−Israel Institute of Technology, Haifa 3200003, Israel
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81
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Role of the electrostatic interactions in the changes in the CN stretching frequency of benzonitrile interacting with hydrogen-bond donating molecules. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.119714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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82
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Freindorf M, Delgado AAA, Kraka E. CO bonding in hexa‐ and pentacoordinate carboxy‐neuroglobin: A quantum mechanics/molecular mechanics and local vibrational mode study. J Comput Chem 2022. [DOI: 10.1002/jcc.26973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Marek Freindorf
- Department of Chemistry Southern Methodist University Dallas Texas USA
| | | | - Elfi Kraka
- Department of Chemistry Southern Methodist University Dallas Texas USA
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83
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Fried SDE, Zheng C, Mao Y, Markland TE, Boxer SG. Solvent Organization and Electrostatics Tuned by Solute Electronic Structure: Amide versus Non-Amide Carbonyls. J Phys Chem B 2022; 126:5876-5886. [PMID: 35901512 PMCID: PMC10081530 DOI: 10.1021/acs.jpcb.2c03095] [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] [Indexed: 11/28/2022]
Abstract
The ability to exploit carbonyl groups to measure electric fields in enzymes and other complex reactive environments by using the vibrational Stark effect has inspired growing interest in how these fields can be measured, tuned, and ultimately designed. Previous studies have concentrated on the role of the solvent in tuning the fields exerted on the solute. Here, we explore instead the role of the solute electronic structure in modifying the local solvent organization and electric field exerted on the solute. By measuring the infrared absorption spectra of amide-containing molecules, as prototypical peptides, and contrasting them with non-amide carbonyls in a wide range of solvents, we show that these solutes experience notable differences in their frequency shifts in polar solvents. Using vibrational Stark spectroscopy and molecular dynamics simulations, we demonstrate that while some of these differences can be rationalized by using the distinct intrinsic Stark tuning rates of the solutes, the larger frequency shifts for amides and dimethylurea primarily result from the larger solvent electric fields experienced by their carbonyl groups. These larger fields arise due to their stronger p-π conjugation, which results in larger C═O bond dipole moments that further induce substantial solvent organization. Using electronic structure calculations, we decompose the electric fields into contributions from solvent molecules that are in the first solvation shell and those from the bulk and show that both of these contributions are significant and become larger with enhanced conjugation in solutes. These results show that structural modifications of a solute can be used to tune both the solvent organization and electrostatic environment, indicating the importance of a solute-centric paradigm in modulating and designing the electrostatic environment in condensed-phase chemical processes.
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Affiliation(s)
- Steven D E Fried
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Chu Zheng
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Yuezhi Mao
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Thomas E Markland
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Steven G Boxer
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
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84
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Lins E, Andvaag IR, Read S, Rosendahl SM, Burgess IJ. Dual-Frequency Comb Spectroscopy Studies of Ionic Strength Effects in Time-Resolved ATR-SEIRAS. J Electroanal Chem (Lausanne) 2022. [DOI: 10.1016/j.jelechem.2022.116672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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85
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Bhattacharyya D, Videla PE, Palasz JM, Tangen I, Meng J, Kubiak CP, Batista VS, Lian T. Sub-Nanometer Mapping of the Interfacial Electric Field Profile Using a Vibrational Stark Shift Ruler. J Am Chem Soc 2022; 144:14330-14338. [PMID: 35905473 DOI: 10.1021/jacs.2c05563] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The characterization of electrical double layers is important since the interfacial electric field and electrolyte environment directly affect the reaction mechanisms and catalytic rates of electrochemical processes. In this work, we introduce a spectroscopic method based on a Stark shift ruler that enables mapping the electric field strength across the electric double layer of electrode/electrolyte interfaces. We use the tungsten-pentacarbonyl(1,4-phenelenediisocyanide) complex attached to the gold surface as a molecular ruler. The carbonyl (CO) and isocyanide (NC) groups of the self-assembled monolayer (SAM) provide multiple vibrational reporters situated at different distances from the electrode. Measurements of Stark shifts under operando electrochemical conditions and direct comparisons to density functional theory (DFT) simulations reveal distance-dependent electric field strength from the electrode surface. This electric field profile can be described by the Gouy-Chapman-Stern model with Stern layer thickness of ∼4.5 Å, indicating substantial solvent and electrolyte penetration within the SAM. Significant electro-induction effect is observed on the W center that is ∼1.2 nm away from the surface despite rapid decay of the electric field (∼90%) within 1 nm. The applied methodology and reported findings should be particularly valuable for the characterization of a wide range of microenvironments surrounding molecular electrocatalysts at electrode interfaces and the positioning of electrocatalysts at specific distances from the electrode surface for optimal functionality.
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Affiliation(s)
- Dhritiman Bhattacharyya
- Department of Chemistry, Emory University, 1515 Dickey Drive Northeast, Atlanta, Georgia 30322, United States
| | - Pablo E Videla
- Department of Chemistry and Energy Sciences Institute, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - Joseph M Palasz
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, MC 0358, La Jolla, San Diego, California 92093, United States
| | - Isaac Tangen
- Department of Chemistry, Emory University, 1515 Dickey Drive Northeast, Atlanta, Georgia 30322, United States
| | - Jinhui Meng
- Department of Chemistry, Emory University, 1515 Dickey Drive Northeast, Atlanta, Georgia 30322, United States
| | - Clifford P Kubiak
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, MC 0358, La Jolla, San Diego, California 92093, United States
| | - Victor S Batista
- Department of Chemistry and Energy Sciences Institute, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - Tianquan Lian
- Department of Chemistry, Emory University, 1515 Dickey Drive Northeast, Atlanta, Georgia 30322, United States
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86
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Matyushov DV. War and Peace between Electrostatic and van der Walls Forces Regulate Translational and Rotational Diffusion. J Chem Phys 2022; 157:080901. [DOI: 10.1063/5.0098506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Diffusion of a Brownian particle or a molecule in a liquid solvent is caused, in the Stokes-Einstein picture, by unbalanced fluctuations of osmotic forces on different sides of the particle. When the particle carries a charge or a higher multipolar moment, this picture is amended by fluctuations of electrostatic forces producing dielectric friction. Dielectric friction slows both the translational and rotational diffusion down. While this picture is well established and is physically sound, standard theories grossly overestimate the magnitude of dielectric friction for small dipolar solutes and larger colloidal particles, such as proteins. Motivated by recent simulation studies, this perspective discusses the interplay between osmotic (van der Waals) and electrostatic forces in promoting molecular and colloidal diffusion. Much can be learned about microscopic friction mechanisms from statistical and dynamical correlations between osmotic and electrostatic forces.
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Affiliation(s)
- Dmitry V. Matyushov
- Departments of Physics and School of Molecular Sciences, Arizona State University, United States of America
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87
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Amante G, Sponer JE, Sponer J, Saija F, Cassone G. A Computational Quantum-Based Perspective on the Molecular Origins of Life’s Building Blocks. ENTROPY 2022; 24:e24081012. [PMID: 35892991 PMCID: PMC9394336 DOI: 10.3390/e24081012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 06/25/2022] [Accepted: 07/18/2022] [Indexed: 12/04/2022]
Abstract
The search for the chemical origins of life represents a long-standing and continuously debated enigma. Despite its exceptional complexity, in the last decades the field has experienced a revival, also owing to the exponential growth of the computing power allowing for efficiently simulating the behavior of matter—including its quantum nature—under disparate conditions found, e.g., on the primordial Earth and on Earth-like planetary systems (i.e., exoplanets). In this minireview, we focus on some advanced computational methods capable of efficiently solving the Schro¨dinger equation at different levels of approximation (i.e., density functional theory)—such as ab initio molecular dynamics—and which are capable to realistically simulate the behavior of matter under the action of energy sources available in prebiotic contexts. In addition, recently developed metadynamics methods coupled with first-principles simulations are here reviewed and exploited to answer to old enigmas and to propose novel scenarios in the exponentially growing research field embedding the study of the chemical origins of life.
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Affiliation(s)
- Gabriele Amante
- Department of Mathematical and Computer Science, Physical Sciences and Earth Sciences, Università degli Studi di Messina, V. le F. Stagno d’Alcontres 31, 98166 Messina, Italy;
| | - Judit E. Sponer
- Institute of Biophysics of the Czech Academy of Sciences (IBP-CAS), Kràlovopolskà 135, 61265 Brno, Czech Republic; (J.E.S.); (J.S.)
| | - Jiri Sponer
- Institute of Biophysics of the Czech Academy of Sciences (IBP-CAS), Kràlovopolskà 135, 61265 Brno, Czech Republic; (J.E.S.); (J.S.)
| | - Franz Saija
- Institute for Physical-Chemical Processes, National Research Council of Italy (IPCF-CNR), V. le F. Stagno d’Alcontres 37, 98158 Messina, Italy
- Correspondence: (F.S.); (G.C.)
| | - Giuseppe Cassone
- Institute for Physical-Chemical Processes, National Research Council of Italy (IPCF-CNR), V. le F. Stagno d’Alcontres 37, 98158 Messina, Italy
- Correspondence: (F.S.); (G.C.)
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88
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Rebstock JA, Zhu Q, Baker LR. Comparing interfacial cation hydration at catalytic active sites and spectator sites on gold electrodes: understanding structure sensitive CO 2 reduction kinetics. Chem Sci 2022; 13:7634-7643. [PMID: 35872825 PMCID: PMC9242014 DOI: 10.1039/d2sc01878k] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 06/09/2022] [Indexed: 12/12/2022] Open
Abstract
Hydrated cations present in the electrochemical double layer (EDL) are known to play a crucial role in electrocatalytic CO2 reduction (CO2R), and numerous studies have attempted to explain how the cation effect contributes to the complex CO2R mechanism. CO2R is a structure sensitive reaction, indicating that a small fraction of total surface sites may account for the majority of catalytic turnover. Despite intense interest in specific cation effects, probing site-specific, cation-dependent solvation structures remains a significant challenge. In this work, CO adsorbed on Au is used as a vibrational Stark reporter to indirectly probe solvation structure using vibrational sum frequency generation (VSFG) spectroscopy. Two modes corresponding to atop adsorption of CO are observed with unique frequency shifts and potential-dependent intensity profiles, corresponding to direct adsorption of CO to inactive surface sites, and in situ generated CO produced at catalytic active sites. Analysis of the cation-dependent Stark tuning slopes for each of these species provides estimates of the hydrated cation radius upon adsorption to active and inactive sites on the Au electrode. While cations are found to retain their bulk hydration shell upon adsorption at inactive sites, catalytic active sites are characterized by a single layer of water between the Au surface and the electrolyte cation. We propose that the drastic increase in catalytic performance at active sites stems from this unique solvation structure at the Au/electrolyte interface. Building on this evidence of a site-specific EDL structure will be critical to understand the connection between cation-dependent interfacial solvation and CO2R performance.
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Affiliation(s)
- Jaclyn A Rebstock
- Department of Chemistry and Biochemistry, The Ohio State University Columbus Ohio 43210 USA
| | - Quansong Zhu
- Department of Chemistry and Biochemistry, The Ohio State University Columbus Ohio 43210 USA
| | - L Robert Baker
- Department of Chemistry and Biochemistry, The Ohio State University Columbus Ohio 43210 USA
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89
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Wu J, Long T, Wang H, Liang JX, Zhu C. Oriented External Electric Fields Regurating the Reaction Mechanism of CH4 Oxidation Catalyzed by Fe(IV)-Oxo-Corrolazine: Insight from Density Functional Calculations. Front Chem 2022; 10:896944. [PMID: 35844657 PMCID: PMC9277104 DOI: 10.3389/fchem.2022.896944] [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: 03/16/2022] [Accepted: 06/08/2022] [Indexed: 11/13/2022] Open
Abstract
Methane is the simplest alkane and can be used as an alternative energy source for oil and coal, but the greenhouse effect caused by its leakage into the air is not negligible, and its conversion into liquid methanol not only facilitates transportation, but also contributes to carbon neutrality. In order to find an efficient method for converting methane to methanol, CH4 oxidation catalyzed by Fe(IV)-Oxo-corrolazine (Fe(IV)-Oxo-Cz) and its reaction mechanism regulation by oriented external electric fields (OEEFs) are systematically studied by density functional calculations. The calculations show that Fe(IV)-Oxo-Cz can abstract one H atom from CH4 to form the intermediate with OH group connecting on the corrolazine ring, with the energy barrier of 25.44 kcal mol−1. And then the product methanol is formed through the following rebound reaction. Moreover, the energy barrier can be reduced to 20.72 kcal mol−1 through a two-state reaction pathway. Furthermore, the effect of OEEFs on the reaction is investigated. We found that OEEFs can effectively regulate the reaction by adjusting the stability of the reactant and the transition state through the interaction of electric field-molecular dipole moment. When the electric field is negative, the energy barrier of the reaction decreases with the increase of electric intensity. Moreover, the OEEF aligned along the intrinsic Fe‒O reaction axis can effectively regulate the ability of forming the OH on the corrolazine ring by adjusting the charges of O and H atoms. When the electric field intensity is −0.010 a.u., the OH can be directly rebounded to the CH3· before it is connecting on the corrolazine ring, thus forming the product directly from the transition state without passing through the intermediate with only an energy barrier of 17.34 kcal mol−1, which greatly improves the selectivity of the reaction.
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Affiliation(s)
| | | | | | | | - Chun Zhu
- *Correspondence: Jin-Xia Liang, ; Chun Zhu,
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90
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Polêto MD, Lemkul JA. TUPÃ: Electric field analyses for molecular simulations. J Comput Chem 2022; 43:1113-1119. [PMID: 35460102 DOI: 10.1002/jcc.26873] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 03/31/2022] [Accepted: 04/08/2022] [Indexed: 11/06/2022]
Abstract
We introduce TUPÃ, a Python-based algorithm to calculate and analyze electric fields in molecular simulations. To demonstrate the features in TUPÃ, we present three test cases in which the orientation and magnitude of the electric field exerted by biomolecules help explain biological phenomena or observed kinetics. As part of TUPÃ, we also provide a PyMOL plugin to help researchers visualize how electric fields are organized within the simulation system. The code is freely available and can be obtained at https://mdpoleto.github.io/tupa/.
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Affiliation(s)
- Marcelo D Polêto
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia, USA.,Center for Drug Discovery, Virginia Tech, Blacksburg, Virginia, USA
| | - Justin A Lemkul
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia, USA.,Center for Drug Discovery, Virginia Tech, Blacksburg, Virginia, USA
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91
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Wright D, Sangtarash S, Mueller NS, Lin Q, Sadeghi H, Baumberg JJ. Vibrational Stark Effects: Ionic Influence on Local Fields. J Phys Chem Lett 2022; 13:4905-4911. [PMID: 35623089 PMCID: PMC9189927 DOI: 10.1021/acs.jpclett.2c01048] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Molecules containing vibrational Stark shift reporters provide a useful tool for measuring DC electric fields in situ. To quantify this effect theoretically, density functional theory (DFT) calculations are usually utilized in a uniform electric field. However, using a combined theoretical and experimental study, we demonstrate here that uniform field DFT cannot simultaneously model the behavior of the three strongest vibrational modes in molecules forming a monolayer on an electrode. We show, by directly modeling ionic movement, that the measured Stark shifts are explained by partial electrical double-layer penetration into the molecular layer. This effect is sensitive to the local environment, and the Stark shifts can be fully suppressed experimentally by introducing a mixed molecular layer that prevents ionic double-layer penetration.
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Affiliation(s)
- Demelza Wright
- NanoPhotonics
Centre, Department of Physics, Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, U.K.
| | - Sara Sangtarash
- Device
Modelling Group, School of Engineering, University of Warwick, Coventry CV4 7AL, U.K.
| | - Niclas S. Mueller
- NanoPhotonics
Centre, Department of Physics, Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, U.K.
| | - Qianqi Lin
- NanoPhotonics
Centre, Department of Physics, Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, U.K.
| | - Hatef Sadeghi
- Device
Modelling Group, School of Engineering, University of Warwick, Coventry CV4 7AL, U.K.
| | - Jeremy J. Baumberg
- NanoPhotonics
Centre, Department of Physics, Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, U.K.
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92
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A two-directional vibrational probe reveals different electric field orientations in solution and an enzyme active site. Nat Chem 2022; 14:891-897. [PMID: 35513508 PMCID: PMC10082611 DOI: 10.1038/s41557-022-00937-w] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 03/25/2022] [Indexed: 12/26/2022]
Abstract
The catalytic power of an electric field depends on its magnitude and orientation with respect to the reactive chemical species. Understanding and designing new catalysts for electrostatic catalysis thus requires methods to measure the electric field orientation and magnitude at the molecular scale. We demonstrate that electric field orientations can be extracted using a two-directional vibrational probe by exploiting the vibrational Stark effect of both the C=O and C-D stretches of a deuterated aldehyde. Combining spectroscopy with molecular dynamics and electronic structure partitioning methods, we demonstrate that, despite distinct polarities, solvents act similarly in their preference for electrostatically stabilizing large bond dipoles at the expense of destabilizing small ones. In contrast, we find that for an active-site aldehyde inhibitor of liver alcohol dehydrogenase, the electric field orientation deviates markedly from that found in solvents, which provides direct evidence for the fundamental difference between the electrostatic environment of solvents and that of a preorganized enzyme active site.
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93
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Bi X, Miao K, Wei L. Alkyne-Tagged Raman Probes for Local Environmental Sensing by Hydrogen-Deuterium Exchange. J Am Chem Soc 2022; 144:8504-8514. [PMID: 35508077 DOI: 10.1021/jacs.2c01991] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Alkyne-tagged Raman probes have shown high promise for noninvasive and sensitive visualization of small biomolecules to understand their functional roles in live cells. However, the potential for alkynes to sense cellular environments that goes beyond imaging remains to be further explored. Here, we report a general strategy for Raman imaging-based local environment sensing by hydrogen-deuterium exchange (HDX) of terminal alkynes (termed alkyne-HDX). We first demonstrate, in multiple Raman probes, that deuterations of the alkynyl hydrogens lead to remarkable shifts of alkyne Raman peaks for about 130 cm-1, providing resolvable signals suited for imaging-based analysis with high specificity. Both our analytical derivation and experimental characterizations subsequently establish that HDX kinetics are linearly proportional to both alkyne pKas and environmental pDs. After validating the quantitative nature of this strategy, we apply alkyne-HDX to sensing local chemical and cellular environments. We establish that alkyne-HDX exhibits high sensitivity to various DNA structures and demonstrates the capacity to detect DNA structural changes in situ from UV-induced damage. We further show that this strategy is also applicable to resolve subtle pD variations in live cells. Altogether, our work lays the foundation for utilizing alkyne-HDX strategy to quantitatively sense the local environments for a broad spectrum of applications in complex biological systems.
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Affiliation(s)
- Xiaotian Bi
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Kun Miao
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Lu Wei
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
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94
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Weaver JB, Kozuch J, Kirsh JM, Boxer SG. Nitrile Infrared Intensities Characterize Electric Fields and Hydrogen Bonding in Protic, Aprotic, and Protein Environments. J Am Chem Soc 2022; 144:7562-7567. [PMID: 35467853 PMCID: PMC10082610 DOI: 10.1021/jacs.2c00675] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Nitriles are widely used vibrational probes; however, the interpretation of their IR frequencies is complicated by hydrogen bonding (H-bonding) in protic environments. We report a new vibrational Stark effect (VSE) that correlates the electric field projected on the -C≡N bond to the transition dipole moment and, by extension, the nitrile peak area or integrated intensity. This linear VSE applies to both H-bonding and non-H-bonding interactions. It can therefore be generally applied to determine electric fields in all environments. Additionally, it allows for semiempirical extraction of the H-bonding contribution to the blueshift of the nitrile frequency. Nitriles were incorporated at H-bonding and non-H-bonding protein sites using amber suppression, and each nitrile variant was structurally characterized at high resolution. We exploited the combined information available from variations in frequency and integrated intensity and demonstrate that nitriles are a generally useful probe for electric fields.
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Affiliation(s)
- Jared Bryce Weaver
- Department of Chemistry, Stanford University, Stanford, California 94305-5012, United States
| | - Jacek Kozuch
- Experimental Molecular Biophysics, Department of Physics, Freie Universität Berlin, 14195 Berlin, Germany
| | - Jacob M Kirsh
- Department of Chemistry, Stanford University, Stanford, California 94305-5012, United States
| | - Steven G Boxer
- Department of Chemistry, Stanford University, Stanford, California 94305-5012, United States
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95
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Kelty ML, McNeece AJ, Kurutz JW, Filatov AS, Anderson JS. Electrostatic vs. inductive effects in phosphine ligand donor properties and reactivity. Chem Sci 2022; 13:4377-4387. [PMID: 35509471 PMCID: PMC9007067 DOI: 10.1039/d1sc04277g] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 03/15/2022] [Indexed: 11/21/2022] Open
Abstract
Enhanced rates and selectivity in enzymes are enabled in part by precisely tuned electric fields within active sites. Analogously, the use of charged groups to leverage electrostatics in molecular systems is a promising strategy to tune reactivity. However, separation of the through space and through bond effects of charged functional groups is a long standing challenge that limits the rational application of electric fields in molecular systems. To address this challenge we developed a method using the phosphorus selenium coupling value (J P-Se) of anionic phosphine selenides to quantify the electrostatic contribution of the borate moiety to donor strength. In this analysis we report the synthesis of a novel anionic phosphine, PPh2CH2BF3K, the corresponding tetraphenyl phosphonium and tetraethyl ammonium selenides [PPh4][SePPh2CH2BF3] and [TEA][SePPh2CH2BF3], and the Rh carbonyl complex [PPh4][Rh(acac)(CO)(PPh2(CH2BF3))]. Solvent-dependent changes in J P-Se were fit using Coulomb's law and support up to an 80% electrostatic contribution to the increase in donor strength of [PPh4][SePPh2CH2BF3] relative to SePPh2Et, while controls with [TEA][SePPh2CH2BF3] exclude convoluting ion pairing effects. Calculations using explicit solvation or point charges effectively replicate the experimental data. This J P-Se method was extended to [PPh4][SePPh2(2-BF3Ph)] and likewise estimates up to a 70% electrostatic contribution to the increase in donor strength relative to SePPh3. The use of PPh2CH2BF3K also accelerates C-F oxidative addition reactivity with Ni(COD)2 by an order of magnitude in comparison to the comparatively donating neutral phosphines PEt3 and PCy3. This enhanced reactivity prompted the investigation of catalytic fluoroarene C-F borylation, with improved yields observed for less fluorinated arenes. These results demonstrate that covalently bound charged functionalities can exert a significant electrostatic influence under common solution phase reaction conditions and experimentally validate theoretical predictions regarding electrostatic effects in reactivity.
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Affiliation(s)
- Margaret L Kelty
- Department of Chemistry, University of Chicago 929 E 57th St Chicago IL 60637 USA
| | - Andrew J McNeece
- Department of Chemistry, University of Chicago 929 E 57th St Chicago IL 60637 USA
| | - Josh W Kurutz
- Department of Chemistry, University of Chicago 929 E 57th St Chicago IL 60637 USA
| | - Alexander S Filatov
- Department of Chemistry, University of Chicago 929 E 57th St Chicago IL 60637 USA
| | - John S Anderson
- Department of Chemistry, University of Chicago 929 E 57th St Chicago IL 60637 USA
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96
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Yu B, Pletka CC, Iwahara J. Protein Electrostatics Investigated through Paramagnetic NMR for Nonpolar Groups. J Phys Chem B 2022; 126:2196-2202. [PMID: 35266708 PMCID: PMC8973454 DOI: 10.1021/acs.jpcb.1c10930] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Experimental validation of theoretical models for protein electrostatics remains rare. Recently, we have developed a paramagnetic NMR-based method for de novo determination of effective near-surface electrostatic potentials, which allows for straightforward examination of electrostatic models for biomolecules. In the current work, we expand this method and demonstrate that effective near-surface electrostatic potentials can readily be determined from 1H paramagnetic relaxation enhancement (PRE) data for protein CαH and CH3 groups. The experimental data were compared with those predicted from the Poisson-Boltzmann theory. The impact of structural dynamics on the effective near-surface electrostatic potentials was also assessed. The agreement between the experimental and theoretical data was particularly good for methyl 1H nuclei. Compared to the conventional pKa-based validation, our paramagnetic NMR-based approach can provide a far larger number of experimental data that can directly be used to examine the validity of theoretical electrostatic models for proteins.
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97
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Zhao R, Shirley JC, Lee E, Grofe A, Li H, Baiz CR, Gao J. Origin of thiocyanate spectral shifts in water and organic solvents. J Chem Phys 2022; 156:104106. [PMID: 35291777 PMCID: PMC8923707 DOI: 10.1063/5.0082969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Vibrational spectroscopy is a useful technique for probing chemical environments. The development of models that can reproduce the spectra of nitriles and azides is valuable because these probes are uniquely suited for investigating complex systems. Empirical vibrational spectroscopic maps are commonly employed to obtain the instantaneous vibrational frequencies during molecular dynamics simulations but often fail to adequately describe the behavior of these probes, especially in its transferability to a diverse range of environments. In this paper, we demonstrate several reasons for the difficulty in constructing a general-purpose vibrational map for methyl thiocyanate (MeSCN), a model for cyanylated biological probes. In particular, we found that electrostatics alone are not a sufficient metric to categorize the environments of different solvents, and the dominant features in intermolecular interactions in the energy landscape vary from solvent to solvent. Consequently, common vibrational mapping schemes do not cover all essential interaction terms adequately, especially in the treatment of van der Waals interactions. Quantum vibrational perturbation (QVP) theory, along with a combined quantum mechanical and molecular mechanical potential for solute-solvent interactions, is an alternative and efficient modeling technique, which is compared in this paper, to yield spectroscopic results in good agreement with experimental FTIR. QVP has been used to analyze the computational data, revealing the shortcomings of the vibrational maps for MeSCN in different solvents. The results indicate that insights from QVP analysis can be used to enhance the transferability of vibrational maps in future studies.
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Affiliation(s)
- Ruoqi Zhao
- Institute of Theoretical Chemistry, Jilin University, Changchun, Jilin Province 130023, China
| | - Joseph C Shirley
- Department of Chemistry, University of Texas, Austin, Texas 78712, USA
| | - Euihyun Lee
- Department of Chemistry, University of Texas, Austin, Texas 78712, USA
| | - Adam Grofe
- Institute of Theoretical Chemistry, Jilin University, Changchun, Jilin Province 130023, China
| | - Hui Li
- Institute of Theoretical Chemistry, Jilin University, Changchun, Jilin Province 130023, China
| | - Carlos R Baiz
- Department of Chemistry, University of Texas, Austin, Texas 78712, USA
| | - Jiali Gao
- Institute of Systems and Physical Biology, Shenzhen Bay Laboratory, Shenzhen 518055, China
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98
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Tao Y, Zou W, Nanayakkara S, Kraka E. LModeA-nano: A PyMOL Plugin for Calculating Bond Strength in Solids, Surfaces, and Molecules via Local Vibrational Mode Analysis. J Chem Theory Comput 2022; 18:1821-1837. [PMID: 35192350 DOI: 10.1021/acs.jctc.1c01269] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The analysis of chemical bonding in crystal structures and surfaces is an important research topic in theoretical chemistry. In this work, we present a PyMOL plugin, named LModeA-nano, as implementation of the local vibrational mode theory for periodic systems (Tao et al. J. Chem. Theory Comput. 2019, 15, 1761) assessing bond strength in terms of local stretching force constants in extended systems of one, two, and three dimensions. LModeA-nano can also analyze chemical bonds in isolated molecular systems thus enabling a head-to-head comparison of bond strength across systems with different dimensions in periodicity (0-3D). The new code is interfaced to the output generated by various solid-state modeling packages including VASP, CP2K, Quantum ESPRESSO, CASTEP, and CRYSTAL. LModeA-nano is cross-platform, open-source and freely available on GitHub: https://github.com/smutao/LModeA-nano.
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Affiliation(s)
- Yunwen Tao
- Department of Chemistry, Southern Methodist University, 3215 Daniel Avenue, Dallas, Texas 75275-0314, United States
| | - Wenli Zou
- Institute of Modern Physics, Northwest University, and Shaanxi Key Laboratory for Theoretical Physics Frontiers, Xi'an, Shaanxi 710127, P. R. China
| | - Sadisha Nanayakkara
- Department of Chemistry, Southern Methodist University, 3215 Daniel Avenue, Dallas, Texas 75275-0314, United States
| | - Elfi Kraka
- Department of Chemistry, Southern Methodist University, 3215 Daniel Avenue, Dallas, Texas 75275-0314, United States
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99
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Zhu Q, Wallentine SK, Deng GH, Rebstock JA, Baker LR. The Solvation-Induced Onsager Reaction Field Rather than the Double-Layer Field Controls CO 2 Reduction on Gold. JACS AU 2022; 2:472-482. [PMID: 35252996 PMCID: PMC8889607 DOI: 10.1021/jacsau.1c00512] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Indexed: 06/14/2023]
Abstract
The selectivity and activity of the carbon dioxide reduction (CO2R) reaction are sensitive functions of the electrolyte cation. By measuring the vibrational Stark shift of in situ-generated CO on Au in the presence of alkali cations, we quantify the total electric field present at catalytic active sites and deconvolute this field into contributions from (1) the electrochemical Stern layer and (2) the Onsager (or solvation-induced) reaction field. Contrary to recent theoretical reports, the CO2R kinetics does not depend on the Stern field but instead is closely correlated with the strength of the Onsager reaction field. These results show that in the presence of adsorbed (bent) CO2, the Onsager field greatly exceeds the Stern field and is primarily responsible for CO2 activation. Additional measurements of the cation-dependent water spectra using vibrational sum frequency generation spectroscopy show that interfacial solvation strongly influences the CO2R activity. These combined results confirm that the cation-dependent interfacial water structure and its associated electric field must be explicitly considered for accurate understanding of CO2R reaction kinetics.
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100
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Boda M, Patwari GN. Vibrational Stark fields in carboxylic acid dimers. Phys Chem Chem Phys 2022; 24:5879-5885. [PMID: 35195127 DOI: 10.1039/d1cp02211c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Carboxylic acids form exceptionally stable dimers and have been used to model proton and double proton transfer processes. The stabilization energies of the carboxylic acid dimers are very weakly dependent on the nature of substitution. However, the electric field experienced by the OH group of a particular carboxylic acid is dependent more on the nature of the substitution on the dimer partner. In general, the electric field was higher when the partner was substituted with an electron-donating group and lower with an electron-withdrawing substituent on the partner. The Stark tuning rate (Δ) of the O-H stretching vibrations calculated at the MP2/aug-cc-pVDZ level was found to be weakly dependent on the nature of substitution on the carboxylic acid. The average Stark tuning rate of O-H stretching vibrations of a particular carboxylic acid when paired with other acids was 5.7 cm-1 (MV cm-1)-1, while the corresponding average Stark tuning rate of the partner acids due to a particular carboxylic acid was 21.9 cm-1 (MV cm-1)-1. The difference in the Stark tuning rate is attributed to the primary and secondary effects of substitution on the carboxylic acid. The average Stark tuning rate for the anharmonic O-D frequency shifts is about 40-50% higher than the corresponding harmonic O-D frequency shifts calculated at the B3LYP/aug-cc-pVDZ level, much greater than the typical scaling factors used, indicating the strong anharmonicity of O-H/O-D oscillators in carboxylic acid dimers. Finally, the linear correlation observed between pKa and the electric field was used to estimate the pKa of fluoroformic acid to be around 0.9.
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Affiliation(s)
- Manjusha Boda
- Department of Chemistry, Indian Institute of Technology Bombay, Powai Mumbai 400076, India.
| | - G Naresh Patwari
- Department of Chemistry, Indian Institute of Technology Bombay, Powai Mumbai 400076, India.
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