1
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Kuan KY, Hsu CP. Predicting Selectivity with a Bifurcating Surface: Inaccurate Model or Inaccurate Statistics of Dynamics? J Phys Chem A 2024; 128:6798-6805. [PMID: 39099446 PMCID: PMC11331512 DOI: 10.1021/acs.jpca.4c04039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2024] [Revised: 07/18/2024] [Accepted: 07/23/2024] [Indexed: 08/06/2024]
Abstract
Reactions on post-transition-state bifurcation (PTSB) energy surfaces are an important class of reaction in which classical rate theories, such as the transition state theory, fail to account for the selectivity. Quasiclassical trajectory molecular dynamic (QCT-MD) simulation is an important computational approach to understanding reactions mechanisms, especially for reactions that cannot be predicted from conventional rate theories. However, the applicability of direct dynamic simulations is hampered by huge computational costs for collecting a statistically meaningful set of trajectories, making it difficult to compare simulation results with theoretical or physical insights-based predictions (non-MD predictions). In this work, we examine the PTSB of Schmidt-Aubé reactions studied by Tantillo and co-workers. With machine-learning using kernel-ridge regression (KRR) to predict atomic forces, statistical reliability was enhanced by significantly increasing the number of trajectories. With KRR, the bottleneck of simulating dynamics (atomic forces in QCT-MD with density functional theory) was accelerated more than 100-fold. We found that this KRR-aided QCT-MD approach is successful in predicting branching ratios with a much larger number of trajectories. With our approach, statistical errors are greatly reduced, and hypothetical non-MD models for predicting selectivity are tested with much higher confidence. By comparison with non-MD models, dynamical properties that affect branching ratios become more clearly described.
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Affiliation(s)
- Kai-Yuan Kuan
- Institute
of Chemistry, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei 11529, Taiwan
| | - Chao-Ping Hsu
- Institute
of Chemistry, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei 11529, Taiwan
- Physics
Division, National Center for Theoretical
Sciences, 1, Section
4, Roosevelt Road, Taipei 106, Taiwan
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2
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Zhou Q, Kukier G, Gordiy I, Hoffmann R, Seeman JI, Houk KN. A 21st Century View of Allowed and Forbidden Electrocyclic Reactions. J Org Chem 2024; 89:1018-1034. [PMID: 38153322 PMCID: PMC10804416 DOI: 10.1021/acs.joc.3c02103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 11/09/2023] [Accepted: 11/15/2023] [Indexed: 12/29/2023]
Abstract
In 1965, Woodward and Hoffmann proposed a theory to predict the stereochemistry of electrocyclic reactions, which, after expansion and generalization, became known as the Woodward-Hoffmann Rules. Subsequently, Longuet-Higgins and Abrahamson used correlation diagrams to propose that the stereoselectivity of electrocyclizations could be explained by the correlation of reactant and product orbitals with the same symmetry. Immediately thereafter, Hoffmann and Woodward applied correlation diagrams to explain the mechanism of cycloadditions. We describe these discoveries and their evolution. We now report an investigation of various electrocyclic reactions using DFT and CASSCF. We track the frontier molecular orbitals along the intrinsic reaction coordinate and modeled trajectories and examine the correlation between HOMO and LUMO for thermally forbidden systems. We also investigate the electrocyclizations of several highly polarized systems for which the Houk group had predicted that donor-acceptor substitution can induce zwitterionic character, thereby providing low-energy pathways for formally forbidden reactions. We conclude with perspectives on the field of pericyclic reactions, including a refinement as the meaning of Woodward and Hoffmann's "Violations. There are none!" Lastly, we comment on the burgeoning influence of computations on all fields of chemistry.
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Affiliation(s)
- Qingyang Zhou
- Department
of Chemistry and Biochemistry, University
of California, Los Angeles, California90095, United States
| | - Garrett Kukier
- Department
of Chemistry and Biochemistry, University
of California, Los Angeles, California90095, United States
| | - Igor Gordiy
- Department
of Chemistry and Biochemistry, University
of California, Los Angeles, California90095, United States
| | - Roald Hoffmann
- Department
of Chemistry and Chemical Biology, Cornell
University, Ithaca, New York14850, United States
| | - Jeffrey I. Seeman
- Department
of Chemistry, University of Richmond, Richmond, Virginia 23173United States
| | - K. N. Houk
- Department
of Chemistry and Biochemistry, University
of California, Los Angeles, California90095-1569. United States
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3
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Seeman JI, Tantillo DJ. Understanding chemistry: from "heuristic (soft) explanations and reasoning by analogy" to "quantum chemistry". Chem Sci 2022; 13:11461-11486. [PMID: 36320403 PMCID: PMC9575397 DOI: 10.1039/d2sc02535c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 09/06/2022] [Indexed: 12/02/2022] Open
Abstract
"Soft theories," i.e., "heuristic models based on reasoning by analogy" largely drove chemistry understanding for 150 years or more. But soft theories have their limitations and with the expansion of chemistry in the mid-20th century, more and more inexplicable (by soft theory) experimental results were being obtained. In the past 50 years, quantum chemistry, most often in the guise of applied theoretical chemistry including computational chemistry, has provided (a) the underlying "hard evidence" for many soft theories and (b) the explanations for chemical phenomena that were unavailable by soft theories. In this publication, we define "hard theories" as "theories derived from quantum chemistry." Both soft and hard theories can be qualitative and quantitative, and the "Houk quadrant" is proposed as a helpful categorization tool. Furthermore, the language of soft theories is often used appropriately to describe quantum chemical results. A valid and useful way of doing science is the appropriate use and application of both soft and hard theories along with the best nomenclature available for successful communication of results and ideas.
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Affiliation(s)
- Jeffrey I Seeman
- Department of Chemistry, University of Richmond Richmond VA 23173 USA
| | - Dean J Tantillo
- Department of Chemistry, University of California - Davis Davis CA 95616 USA
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4
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Gutowski Ł, Liszewska M, Bartosewicz B, Budner B, Weyher JL, Jankiewicz BJ. Investigation of organic monoradicals reactivity using surface-enhanced Raman spectroscopy. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2022; 278:121312. [PMID: 35537259 DOI: 10.1016/j.saa.2022.121312] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 03/28/2022] [Accepted: 04/23/2022] [Indexed: 06/14/2023]
Abstract
Surface-enhanced Raman spectroscopy (SERS) and self-assembled monolayer (SAM) approaches were used to investigate the reactions of organic monoradicals with methanol. An attempt was made to generate monoradicals from thiophenols and phenylmethanethiols substituted with bromine, iodine, and nitro groups by irradiation with UV light. Monolayers of radical precursors were deposited on SERS substrates, which were then immersed in methanol and irradiated for 1 and/or 3, 6, 12 and 24 h in a UV photochemical reactor. Pre- and postreaction SERS spectra were obtained by using a confocal Raman microscope and compared with the spectra of expected products of the radical reaction with methanol. Our studies have shown that the efficiency of monoradical generation is highly dependent on the chemical structure of the precursor. In addition, it is shown that both the SERS substrate and experimental conditions used strongly influence the obtained results.
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Affiliation(s)
- Łukasz Gutowski
- Institute of Optoelectronics, Military University of Technology, gen. Sylwestra Kaliskiego 2, 00-908 Warsaw, Poland.
| | - Malwina Liszewska
- Institute of Optoelectronics, Military University of Technology, gen. Sylwestra Kaliskiego 2, 00-908 Warsaw, Poland.
| | - Bartosz Bartosewicz
- Institute of Optoelectronics, Military University of Technology, gen. Sylwestra Kaliskiego 2, 00-908 Warsaw, Poland.
| | - Bogusław Budner
- Institute of Optoelectronics, Military University of Technology, gen. Sylwestra Kaliskiego 2, 00-908 Warsaw, Poland.
| | - Jan L Weyher
- Institute of High-Pressure Physics, Polish Academy of Sciences, Sokołowska 29/37, 01-142 Warsaw, Poland.
| | - Bartłomiej J Jankiewicz
- Institute of Optoelectronics, Military University of Technology, gen. Sylwestra Kaliskiego 2, 00-908 Warsaw, Poland.
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5
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Abstract
Differences in entropies of competing transition states can direct kinetic selectivity. Understanding and modeling such entropy differences at the molecular level is complicated by the fact that entropy is statistical in nature; i.e., it depends on multiple vibrational states of transition structures, the existence of multiple dynamically accessible pathways past these transition structures, and contributions from multiple transition structures differing in conformation/configuration. The difficulties associated with modeling each of these contributors are discussed here, along with possible solutions, all with an eye toward the development of portable qualitative models of use to experimentalists aiming to design reactions that make use of entropy to control kinetic selectivity.
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Affiliation(s)
- Dean J Tantillo
- Department of Chemistry, University of California-Davis, 1 Shields Ave, Davis, California 95616, United States
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6
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Fey N, Lynam JM. Computational mechanistic study in organometallic catalysis: Why prediction is still a challenge. WIRES COMPUTATIONAL MOLECULAR SCIENCE 2022. [DOI: 10.1002/wcms.1590] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Natalie Fey
- School of Chemistry University of Bristol, Cantock's Close Bristol UK
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7
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Rush LA, Gallo KF, Stumetz KS, Rodríguez‐Pérez IA, Cremeens ME. Non‐statistical Dynamics for the Allene Oxide to Cyclopropanone Conversion. J PHYS ORG CHEM 2022. [DOI: 10.1002/poc.4385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Lydia A. Rush
- Department of Chemistry and Biochemistry Gonzaga University Spokane Washington United States
| | - Kara F. Gallo
- Department of Chemistry and Biochemistry Gonzaga University Spokane Washington United States
| | - Kyle S. Stumetz
- Department of Chemistry and Biochemistry Gonzaga University Spokane Washington United States
| | | | - Matthew E. Cremeens
- Department of Chemistry and Biochemistry Gonzaga University Spokane Washington United States
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8
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Lan J, Li X, Yang Y, Zhang X, Chung LW. New Insights and Predictions into Complex Homogeneous Reactions Enabled by Computational Chemistry in Synergy with Experiments: Isotopes and Mechanisms. Acc Chem Res 2022; 55:1109-1123. [PMID: 35385649 DOI: 10.1021/acs.accounts.1c00774] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Homogeneous catalysis and biocatalysis have been widely applied in synthetic, medicinal, and energy chemistry as well as synthetic biology. Driven by developments of new computational chemistry methods and better computer hardware, computational chemistry has become an essentially indispensable mechanistic "instrument" to help understand structures and decipher reaction mechanisms in catalysis. In addition, synergy between computational and experimental chemistry deepens our mechanistic understanding, which further promotes the rational design of new catalysts. In this Account, we summarize new or deeper mechanistic insights (including isotope, dispersion, and dynamical effects) into several complex homogeneous reactions from our systematic computational studies along with subsequent experimental studies by different groups. Apart from uncovering new mechanisms in some reactions, a few computational predictions (such as excited-state heavy-atom tunneling, steric-controlled enantioswitching, and a new geminal addition mechanism) based on our mechanistic insights were further verified by ensuing experiments.The Zimmerman group developed a photoinduced triplet di-π-methane rearrangement to form cyclopropane derivatives. Recently, our computational study predicted the first excited-state heavy-atom (carbon) quantum tunneling in one triplet di-π-methane rearrangement, in which the reaction rates and 12C/13C kinetic isotope effects (KIEs) can be enhanced by quantum tunneling at low temperatures. This unprecedented excited-state heavy-atom tunneling in a photoinduced reaction has recently been verified by an experimental 12C/13C KIE study by the Singleton group. Such combined computational and experimental studies should open up opportunities to discover more rare excited-state heavy-atom tunneling in other photoinduced reactions. In addition, we found unexpectedly large secondary KIE values in the five-coordinate Fe(III)-catalyzed hetero-Diels-Alder pathway, even with substantial C-C bond formation, due to the non-negligible equilibrium isotope effect (EIE) derived from altered metal coordination. Therefore, these KIE values cannot reliably reflect transition-state structures for the five-coordinate metal pathway. Furthermore, our density functional theory (DFT) quasi-classical molecular dynamics (MD) simulations demonstrated that the coordination mode and/or spin state of the iron metal as well as an electric field can affect the dynamics of this reaction (e.g., the dynamically stepwise process, the entrance/exit reaction channels).Moreover, we unveiled a new reaction mechanism to account for the uncommon Ru(II)-catalyzed geminal-addition semihydrogenation and hydroboration of silyl alkynes. Our proposed key gem-Ru(II)-carbene intermediates derived from double migrations on the same alkyne carbon were verified by crossover experiments. Additionally, our DFT MD simulations suggested that the first hydrogen migration transition-state structures may directly and quickly form the key gem-Ru-carbene structures, thereby "bypassing" the second migration step. Furthermore, our extensive study revealed the origin of the enantioselectivity of the Cu(I)-catalyzed 1,3-dipolar cycloaddition of azomethine ylides with β-substituted alkenyl bicyclic heteroarenes enabled by dual coordination of both substrates. Such mechanistic insights promoted our computational predictions of the enantioselectivity reversal for the corresponding monocyclic heteroarene substrates and the regiospecific addition to the less reactive internal C═C bond of one diene substrate. These predictions were proven by our experimental collaborators. Finally, our mechanistic insights into a few other reactions are also presented. Overall, we hope that these interactive computational and experimental studies enrich our mechanistic understanding and aid in reaction development.
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Affiliation(s)
- Jialing Lan
- School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, China
- Shenzhen Grubbs Institute, Department of Chemistry, and Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology (SUSTech), Shenzhen 518055, China
| | - Xin Li
- Shenzhen Grubbs Institute, Department of Chemistry, and Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology (SUSTech), Shenzhen 518055, China
| | - Yuhong Yang
- Shenzhen Grubbs Institute, Department of Chemistry, and Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology (SUSTech), Shenzhen 518055, China
| | - Xiaoyong Zhang
- Shenzhen Grubbs Institute, Department of Chemistry, and Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology (SUSTech), Shenzhen 518055, China
| | - Lung Wa Chung
- Shenzhen Grubbs Institute, Department of Chemistry, and Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology (SUSTech), Shenzhen 518055, China
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9
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Dale HJA, Leach AG, Lloyd-Jones GC. Heavy-Atom Kinetic Isotope Effects: Primary Interest or Zero Point? J Am Chem Soc 2021; 143:21079-21099. [PMID: 34870970 DOI: 10.1021/jacs.1c07351] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Chemists have many options for elucidating reaction mechanisms. Global kinetic analysis and classic transition-state probes (e.g., LFERs, Eyring) inevitably form the cornerstone of any strategy, yet their application to increasingly sophisticated synthetic methodologies often leads to a wide range of indistinguishable mechanistic proposals. Computational chemistry provides powerful tools for narrowing the field in such cases, yet wholly simulated mechanisms must be interpreted with great caution. Heavy-atom kinetic isotope effects (KIEs) offer an exquisite but underutilized method for reconciling the two approaches, anchoring the theoretician in the world of calculable observables and providing the experimentalist with atomistic insights. This Perspective provides a personal outlook on this synergy. It surveys the computation of heavy-atom KIEs and their measurement by NMR spectroscopy, discusses recent case studies, highlights the intellectual reward that lies in alignment of experiment and theory, and reflects on the changes required in chemical education in the area.
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Affiliation(s)
- Harvey J A Dale
- EaStChem, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, U.K
| | - Andrew G Leach
- School of Health Sciences, The University of Manchester, Stopford Building, Oxford Road, Manchester M13 9PT, U.K
| | - Guy C Lloyd-Jones
- EaStChem, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, U.K
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10
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Zhang X, Lefebvre PL, Harvey JN. Effect of solvent motions on the dynamics of the Diels-Alder reaction. Phys Chem Chem Phys 2021; 24:1120-1130. [PMID: 34928279 DOI: 10.1039/d1cp05272a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
How solvent motions affect the dynamics of chemical reactions in which the solute undergoes a substantial shape change is a fundamental but elusive issue. This work utilizes reactive simulation and Grote-Hynes theory to explore the effect of solvent motions on the dynamics of the Diels-Alder reaction (in the reverse direction, this reaction involves very substantial solute expansion) in aprotic solvents. The results reveal that the solvent environment is not sufficiently constraining to influence transition state passage dynamics, with the calculated transmission coefficients being close to unity. Even when solvent motions are suppressed or artificially slowed down, the solvent only affects the reaction dynamics in the transition state region to a very small extent. The only notable effect of solvent occurs far from the transition state region and corresponds to caging of the reactants within the reactant well.
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Affiliation(s)
- Xiaoyong Zhang
- Theoretical and Computational Chemistry, Department of Chemistry, KU Leuven Celestijnenlaan 200F, 3001, Leuven, Belgium.
| | - Pierre-Louis Lefebvre
- Theoretical and Computational Chemistry, Department of Chemistry, KU Leuven Celestijnenlaan 200F, 3001, Leuven, Belgium. .,Quantum Theory Project, Departments of Chemistry and Physics, University of Florida, Gainesville, Florida 32611, USA
| | - Jeremy N Harvey
- Theoretical and Computational Chemistry, Department of Chemistry, KU Leuven Celestijnenlaan 200F, 3001, Leuven, Belgium.
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11
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Abstract
Photochemical reactions are increasingly being used for chemical and materials synthesis, for example, in photoredox catalysis, and generally involve photoexcitation of molecular chromophores dissolved in a liquid solvent. The choice of solvent influences the outcomes of the photochemistry because solute-solvent interactions modify the energies of and crossings between electronic states of the chromophores, and they affect the evolving structures of the photoexcited molecules. Ultrafast laser spectroscopy methods with femtosecond to picosecond time resolution can resolve the dynamics of these photoexcited molecules as they undergo structural and electronic changes, relax back to the ground state, dissipate their excess internal energy to the surrounding solvent, or undergo photochemical reactions. In this Account, we illustrate how experimental studies using ultrafast lasers can reveal the influences that different solvents or cosolutes exert on the photoinduced nonadiabatic dynamics of internal conversion and intersystem crossing in nonradiative relaxation pathways. Although the environment surrounding a solute molecule is rapidly changing, with fluctuations in the coordination to neighboring solvent molecules occurring on femtosecond or picosecond time scales, we show that it is possible to photoexcite selectively only those molecular chromophores transiently experiencing specific solute-solvent interactions such as intermolecular hydrogen bonding.The effects of different solvation environments on the photodynamics are illustrated using four selected examples of photochemical processes in which the solvent has a marked effect on the outcomes. We first consider two aromatic carbonyl compounds, benzophenone and acetophenone, which are known to undergo fast intersystem crossing to populate the first excited triplet state on time scales of a few picoseconds. We show that the nonadiabatic excited-state dynamics are modified by transient hydrogen bonding of the carbonyl group to a protic solvent or by coordination to a metal cation cosolute. We then examine how different solvents modify the competition between two alternative relaxation pathways in a photoexcited UVA-sunscreen molecule, diethylamino hydroxybenzoyl hexyl benzoate (DHHB). This relaxation back to the ground electronic state is an essential part of the effective operation of the sunscreen compound, but the dynamics are sensitive to the surrounding environment. Finally, we consider how solvents of different polarity affect the energies and lifetimes of excited states with locally excited or charge-transfer character in heterocyclic organic compounds used as excited-state electron donors for photoredox catalysis. With these and other examples, we seek to develop a molecular level understanding of how the choice of solution environment might be used to control the outcomes of photochemical reactions.
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Affiliation(s)
- Ravi Kumar Venkatraman
- School of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, United Kingdom
| | - Andrew J. Orr-Ewing
- School of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, United Kingdom
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12
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Tantillo DJ, Laconsay CJ. Melding of Experiment and Theory Illuminates Mechanisms of Metal-Catalyzed Rearrangements: Computational Approaches and Caveats. SYNTHESIS-STUTTGART 2021. [DOI: 10.1055/s-0040-1720451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
AbstractThis review summarizes approaches and caveats in computational modeling of transition-metal-catalyzed sigmatropic rearrangements involving carbene transfer. We highlight contemporary examples of combined synthetic and theoretical investigations that showcase the synergy achievable by integrating experiment and theory.1 Introduction2 Mechanistic Models3 Theoretical Approaches and Caveats3.1 Recommended Computational Tools3.2 Choice of Functional and Basis Set3.3 Conformations and Ligand-Binding Modes3.4 Solvation4 Synergy of Experiment and Theory – Case Studies4.1 Metal-Bound or Free Ylides?4.2 Conformations and Ligand-Binding Modes of Paddlewheel Complexes4.3 No Metal, Just Light4.4 How To ‘Cope’ with Nonstatistical Dynamic Effects5 Outlook
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13
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Huang T, Li B, Wang H, Granick S. Molecules, the Ultimate Nanomotor: Linking Chemical Reaction Intermediates to their Molecular Diffusivity. ACS NANO 2021; 15:14947-14953. [PMID: 34523903 DOI: 10.1021/acsnano.1c05168] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The intellectual community focused on nanomotors has recently become interested in extending these concepts to individual molecules. Here, we study a chemical reaction according to whose mechanism some intermediate species should speed up while others slow down in predictable ways, if the nanomotor hypothesis of boosted diffusion holds. Accordingly, we scrutinize the absolute diffusion coefficient (D) during intermediate steps of the catalytic cycle for the CuAAC reaction (copper-catalyzed azide-alkyne cycloaddition click reaction), using proton pulsed field-gradient nuclear magnetic resonance to discriminate between the diffusion of various reaction intermediates. We observe time-dependent diffusion that is enhanced for some intermediate molecular species and depressed for those whose size increases owing to complex formation. These findings point to the failure of the conventional Stokes-Einstein equation to fully explain diffusivity during chemical reaction. Without attempting a firm explanation, this paper highlights aspects of the physics of chemical reactions that are imperfectly understood and presents systematic data that can be used to assess hypotheses.
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Affiliation(s)
- Tian Huang
- Center for Soft and Living Matter, Institute for Basic Science (IBS), Ulsan 44919, South Korea
| | - Bo Li
- Center for Soft and Living Matter, Institute for Basic Science (IBS), Ulsan 44919, South Korea
| | - Huan Wang
- College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, People's Republic of China
| | - Steve Granick
- Center for Soft and Living Matter, Institute for Basic Science (IBS), Ulsan 44919, South Korea
- Departments of Chemistry and Physics, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, South Korea
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14
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Yu M, Ge X, Zhou S. On the origins of the mechanistic variants in the thermal reactions of S x+ (x = 1-3) with benzene. Phys Chem Chem Phys 2021; 23:17512-17520. [PMID: 34364310 DOI: 10.1039/d1cp01959g] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The S-π interaction between sulfur atom(s) and aromatic ring prevails in chemical and biochemical processes. The thermal gas-phase reactions of the Sn+ (n = 1-3) ions with benzene have been explored by using Quadrupole-Ion Trap (Q-IT) mass spectrometry complemented by quantum chemical calculations. Charge transfer was found to be the only reaction channel for S2+/C6H6, while both charge transfer and bond activation are available for the S+/C6H6 and S3+/C6H6 couples. Upon interrogating the associated electronic origins, multiple factors were found to matter for these processes. In contrast to the σ-type two-center three-electron (2c-3e) S-π hemibond as reported previously, unusual S-π hemibonds were addressed for the Sn+/C6H6 couples, i.e. the 2c-3e π(S061Eπ) and the three-center three-electron (3c-3e) σ(S2061Eπ) hemibonds. Such S-π interaction was found to be responsible for the charge transfer processes in S+/C6H6 and S2+/C6H6, but uninvolved in any transformation for S3+/C6H6.
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Affiliation(s)
- Mincheng Yu
- College of Chemical and Biological Engineering, Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology, Zhejiang University, 310027 Hangzhou, P. R. China.
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15
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Maley SM, Melville J, Yu S, Teynor MS, Carlsen R, Hargis C, Hamilton RS, Grant BO, Ess DH. Machine learning classification of disrotatory IRC and conrotatory non-IRC trajectory motion for cyclopropyl radical ring opening. Phys Chem Chem Phys 2021; 23:12309-12320. [PMID: 34018524 DOI: 10.1039/d1cp00612f] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Quasiclassical trajectory analysis is now a standard tool to analyze non-minimum energy pathway motion of organic reactions. However, due to the large amount of information associated with trajectories, quantitative analysis of the dynamic origin of reaction selectivity is complex. For the electrocyclic ring opening of cyclopropyl radical, more than 4000 trajectories were run showing that allyl radicals are formed through a mixture of disrotatory intrinsic reaction coordinate (IRC) motion as well as conrotatory non-IRC motion. Geometric, vibrational mode, and atomic velocity transition-state features from these trajectories were used for supervised machine learning analysis with classification algorithms. Accuracy >80% with a random forest model enabled quantitative and qualitative assessment of transition-state trajectory features controlling disrotatory IRC versus conrotatory non-IRC motion. This analysis revealed that there are two key vibrational modes where their directional combination provides prediction of IRC versus non-IRC motion.
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Affiliation(s)
- Steven M Maley
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, USA.
| | - Jesse Melville
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, USA.
| | - Spencer Yu
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, USA.
| | - Matthew S Teynor
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, USA.
| | - Ryan Carlsen
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, USA.
| | - Cal Hargis
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, USA.
| | - R Spencer Hamilton
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, USA.
| | - Benjamin O Grant
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, USA.
| | - Daniel H Ess
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, USA.
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16
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Biasin E, Fox ZW, Andersen A, Ledbetter K, Kjær KS, Alonso-Mori R, Carlstad JM, Chollet M, Gaynor JD, Glownia JM, Hong K, Kroll T, Lee JH, Liekhus-Schmaltz C, Reinhard M, Sokaras D, Zhang Y, Doumy G, March AM, Southworth SH, Mukamel S, Gaffney KJ, Schoenlein RW, Govind N, Cordones AA, Khalil M. Direct observation of coherent femtosecond solvent reorganization coupled to intramolecular electron transfer. Nat Chem 2021; 13:343-349. [PMID: 33589787 DOI: 10.1038/s41557-020-00629-3] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 12/14/2020] [Indexed: 01/31/2023]
Abstract
It is well known that the solvent plays a critical role in ultrafast electron-transfer reactions. However, solvent reorganization occurs on multiple length scales, and selectively measuring short-range solute-solvent interactions at the atomic level with femtosecond time resolution remains a challenge. Here we report femtosecond X-ray scattering and emission measurements following photoinduced charge-transfer excitation in a mixed-valence bimetallic (FeiiRuiii) complex in water, and their interpretation using non-equilibrium molecular dynamics simulations. Combined experimental and computational analysis reveals that the charge-transfer excited state has a lifetime of 62 fs and that coherent translational motions of the first solvation shell are coupled to the back electron transfer. Our molecular dynamics simulations identify that the observed coherent translational motions arise from hydrogen bonding changes between the solute and nearby water molecules upon photoexcitation, and have an amplitude of tenths of ångströms, 120-200 cm-1 frequency and ~100 fs relaxation time. This study provides an atomistic view of coherent solvent reorganization mediating ultrafast intramolecular electron transfer.
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Affiliation(s)
- Elisa Biasin
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, CA, USA.
| | - Zachary W Fox
- Department of Chemistry, University of Washington, Seattle, WA, USA
| | - Amity Andersen
- Environmental Molecular Sciences Division, Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Kathryn Ledbetter
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Kasper S Kjær
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, CA, USA.,Department of Physics, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Roberto Alonso-Mori
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Julia M Carlstad
- Department of Chemistry, University of Washington, Seattle, WA, USA.,Department of Chemistry, University of California, Berkeley, CA, USA
| | - Matthieu Chollet
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - James D Gaynor
- Department of Chemistry, University of Washington, Seattle, WA, USA.,Department of Chemistry, University of California, Berkeley, CA, USA
| | - James M Glownia
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Kiryong Hong
- Ultrafast X-ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.,Gas Metrology Group, Division of Chemical and Biological Metrology, Korea Research Institute of Standards and Science, Daejeon, Republic of Korea
| | - Thomas Kroll
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Jae Hyuk Lee
- Ultrafast X-ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.,Pohang Accelerator Laboratory, Pohang, Republic of Korea
| | | | - Marco Reinhard
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Dimosthenis Sokaras
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Yu Zhang
- Department of Chemistry, Physics, and Astronomy, University of California, Irvine, CA, USA.,Q-Chem, Pleasanton, CA, USA
| | - Gilles Doumy
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, IL, USA
| | - Anne Marie March
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, IL, USA
| | - Stephen H Southworth
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, IL, USA
| | - Shaul Mukamel
- Department of Chemistry, Physics, and Astronomy, University of California, Irvine, CA, USA
| | - Kelly J Gaffney
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Robert W Schoenlein
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, CA, USA.,Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Niranjan Govind
- Physical Sciences Division, Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, USA.
| | - Amy A Cordones
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, CA, USA.
| | - Munira Khalil
- Department of Chemistry, University of Washington, Seattle, WA, USA.
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17
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Tantillo DJ. Dynamic effects on organic reactivity—Pathways to (and from) discomfort. J PHYS ORG CHEM 2021. [DOI: 10.1002/poc.4202] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Dean J. Tantillo
- Department of Chemistry University of California, Davis Davis California USA
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18
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Ansari T, Jasinski JB, Leahy DK, Handa S. Metal-Micelle Cooperativity: Phosphine Ligand-Free Ultrasmall Palladium(II) Nanoparticles for Oxidative Mizoroki-Heck-type Couplings in Water at Room Temperature. JACS AU 2021; 1:308-315. [PMID: 34467295 PMCID: PMC8395633 DOI: 10.1021/jacsau.0c00087] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Indexed: 05/08/2023]
Abstract
The amphiphile PS-750-M generates stable, phosphine ligand-free, and catalytically active ultrasmall Pd(II) nanoparticles (NPs) from Pd(OAc)2, preventing their precipitation, polymerization, and oxidation state changes. PS-750-M directly interacts with Pd(II) NP surfaces, as confirmed by high-resolution mass spectrometry and IR spectroscopy, resulting in their high stability. The Pd cations in NPs are most likely held together by hydroxides and acetate ions. The NPs were characterized by HRTEM, revealing their morphology and particle size distribution, and by HRMS and IR, providing evidence for NP-amphiphile interaction. The NP catalytic activity was examined in the context of oxidative Mizoroki-Heck-type couplings in water at room temperature. Hot filtration, hot extraction, and three-phase tests indicate heterogeneous catalysis occurring at the micellar interface rather than homogeneous catalysis occurring in the solution. NMR studies indicate that the catalytic activity stems from metal cation-π interactions of the styrene along with transmetalation by the arylboronic acid, followed by insertion and β-H elimination to furnish the coupled product along with the reoxidation of Pd by benzoquinone to complete the catalytic cycle. This method is very mild and sustainable, both in terms of NP synthesis and subsequent catalysis, and shows broad substrate scope while circumventing the need for organic solvents for this important class of couplings.
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Affiliation(s)
- Tharique
N. Ansari
- Department
of Chemistry, University of Louisville, Louisville, Kentucky 40292, United States
| | - Jacek B. Jasinski
- Conn
Center for Renewable Energy Research, University
of Louisville, Louisville, Kentucky 40292, United States
| | - David K. Leahy
- Process
Chemistry Development, Takeda Pharmaceuticals
International, Cambridge, Massachusetts 02139, United States
| | - Sachin Handa
- Department
of Chemistry, University of Louisville, Louisville, Kentucky 40292, United States
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19
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Zhang X, Vázquez SA, Harvey JN. Vibrational Energy Relaxation of Deuterium Fluoride in d-Dichloromethane: Insights from Different Potentials. J Chem Theory Comput 2021; 17:1277-1289. [PMID: 33550803 DOI: 10.1021/acs.jctc.0c01059] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Vibrationally excited deuterium fluoride (DF) formed by fluorine atom reaction with a solvent was found (Science, 2015, 347, 530) to relax rapidly (less than 10 ps) in acetonitrile-d3 (CD3CN) and dichloromethane-d2 (CD2Cl2). However, insights into how CD2Cl2 facilitates this energy relaxation have so far been lacking, given the weak interaction between DF and a single CD2Cl2. In this work, we report the results of reactive simulations with a two-state reactive empirical valence bond (EVB) potential to study the energy deposited into nascent DF after transition-state passage and of nonequilibrium molecular dynamics simulations using multiple different potential energy functions to model the relaxation dynamics. For these second simulations, we used the standard Merck molecular force field (MMFF) potential, an MMFF-based covalent-ionic empirical valence bond (EVB) potential (EVBCI), a newly developed potential [referred to as MMFF(rDF)] which extends upon the MMFF potential by making the DF/CD2Cl2 interaction depend on the value of the D-F bond stretching coordinate and by taking the anisotropic charge distribution of the solvent molecules into account, the polarizable atomic multipole optimized energetics for biomolecular applications (AMOEBA) potential, and the quantum mechanics/molecular mechanics (QM/MM) potential. The relaxation is revealed to be highly sensitive to the potential used. Neither standard MMFF nor EVBCI reproduces the experimentally observed rapid relaxation dynamics, and they also fail to provide a good description of the interaction potential between DF and CD2Cl2 as calculated using CCSD(T)-F12. This is attributed to the use of a point-charge model for the solute and to failing to model the anisotropic electrostatic properties of CD2Cl2. The MMFF(rDF), AMOEBA, and QM/MM potentials all reproduce the CCSD(T)-F12 two-body DF---CD2Cl2 interaction potential rather well but only with the QM/MM approach is fast vibrational relaxation obtained (lifetimes of ∼288, ∼186, and ∼8 ps, respectively), which we attribute to differences in the solute-solvent local structure. With QM/MM, a unique "many-body" interaction pattern in which DF is in close contact with two solvent Cl atoms and more than three solvent D atoms is found, but this structure is not seen with other potentials. The QM/MM dynamics also display enhanced solute-solvent interactions with vibrationally excited DF that induce a DF band redshift and hence a resonant overlap with solvent C-D modes, which facilitate the intermolecular energy transfer. Our work also suggests that potentials used to model energy relaxation need to capture the fine structure of solute-solvent interactions and not just the two-body part.
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Affiliation(s)
- Xiaoyong Zhang
- Department of Chemistry and Division of Quantum Chemistry and Physical Chemistry, KU Leuven, Celestijnenlaan 200F, Leuven B-3001, Belgium
| | - Saulo A Vázquez
- Departamento de Química Física, Facultade de Química, Universidade de Santiago de Compostela, Santiago de Compostela 15782, Spain
| | - Jeremy N Harvey
- Department of Chemistry and Division of Quantum Chemistry and Physical Chemistry, KU Leuven, Celestijnenlaan 200F, Leuven B-3001, Belgium
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20
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Patel A, Patel A. Synthesis and characterization of supported stabilized palladium nanoparticles for selective hydrogenation in water at low temperature. RSC Adv 2021; 11:8218-8227. [PMID: 35423350 PMCID: PMC8695083 DOI: 10.1039/d1ra00239b] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 02/12/2021] [Indexed: 12/24/2022] Open
Abstract
Zirconia supported vacant phosphotungstate stabilized Pd nanoparticles (Pd-PW11/ZrO2) were prepared using a simple impregnation and post reduction method, characterized and their efficiency for selective C[double bond, length as m-dash]C hydrogenation of unsaturated compounds explored. The establishment of a hydrogenation strategy at low temperature using water as solvent under mild conditions makes the present system environmentally benign and green. The catalyst shows outstanding activity (96% conversion) with just a small amount of Pd(0) (0.0034 mol%) with high substrate/catalyst ratio (29 177/1), TON (28 010) and TOF (14 005 h-1) for cyclohexene (as a model substrate) hydrogenation. The catalyst was recovered by simple centrifugation and reused for up to five catalytic cycles without alteration in its activity. The present catalyst was found to be viable towards different substrates with excellent activity and TON (18 000 to 28 800). A study on the effect of addenda atom shows that the efficiency of the catalyst can be enhanced greatly by increasing the number of counter protons. This challenging strategy would greatly benefit sustainable development in chemistry as it diminishes the use of organic solvents and offers economic and environmental benefits as water is cheap and non-toxic.
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Affiliation(s)
- Anish Patel
- Polyoxometalates and Catalysis Laboratory, Department of Chemistry, Faculty of Science, The Maharaja Sayajirao University of Baroda Vadodara-390002 Gujarat India
| | - Anjali Patel
- Polyoxometalates and Catalysis Laboratory, Department of Chemistry, Faculty of Science, The Maharaja Sayajirao University of Baroda Vadodara-390002 Gujarat India
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21
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Chae Y, Min S, Park E, Lim C, Cheon CH, Jeong K, Kwak K, Cho M. Real-Time Reaction Monitoring with In Operando Flow NMR and FTIR Spectroscopy: Reaction Mechanism of Benzoxazole Synthesis. Anal Chem 2021; 93:2106-2113. [PMID: 33389991 DOI: 10.1021/acs.analchem.0c03852] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
In operando observation of reaction intermediates is crucial for unraveling reaction mechanisms. To address the sensitivity limitations of commercial ReactIR, a flow cell was integrated with a Fourier transform infrared (FTIR) spectrometer yielding a "flow FTIR" device coupled with an NMR spectrometer for the elucidation of reaction mechanisms. The former device detects the low-intensity IR peaks of reaction intermediates by adjusting the path length of the FTIR sample cell, whereas the flow NMR allows the quantitative analysis of reaction species, thus offsetting the limitations of IR spectroscopy resulting from different absorption coefficients of the normal modes. Using the flow NMR and FTIR device, the controversial mechanism of benzoxazole synthesis was conclusively determined by spectroscopic evaluation of the reaction intermediates. This system enabled the accurate acquisition of previously elusive kinetic data, such as the reaction time and rate-determining step. The implementation of reaction flow cells into NMR and FTIR systems could be widely applied to study various reaction mechanisms, including dangerous and harsh reactions, thus avoiding contact with potentially harmful reaction intermediates.
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Affiliation(s)
- Yeongseok Chae
- Center of Molecular Spectroscopy and Dynamics, Institute of Basic Science (IBS), Seoul 02841, South Korea.,Department of Chemistry, Korea University, Seoul 02841, South Korea
| | - Sein Min
- Department of Chemistry, Seoul Women's University, Seoul 01797, South Korea
| | - Eunjoon Park
- Department of Chemistry, Korea University, Seoul 02841, South Korea
| | - Chaiho Lim
- Center of Molecular Spectroscopy and Dynamics, Institute of Basic Science (IBS), Seoul 02841, South Korea.,Department of Chemistry, Korea University, Seoul 02841, South Korea
| | - Cheol-Hong Cheon
- Department of Chemistry, Korea University, Seoul 02841, South Korea
| | - Keunhong Jeong
- Department of Chemistry, Korea Military Academy, Seoul 01805, South Korea
| | - Kyungwon Kwak
- Center of Molecular Spectroscopy and Dynamics, Institute of Basic Science (IBS), Seoul 02841, South Korea.,Department of Chemistry, Korea University, Seoul 02841, South Korea
| | - Minhaeng Cho
- Center of Molecular Spectroscopy and Dynamics, Institute of Basic Science (IBS), Seoul 02841, South Korea.,Department of Chemistry, Korea University, Seoul 02841, South Korea
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22
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Fu Y, Bernasconi L, Liu P. Ab Initio Molecular Dynamics Simulations of the S N1/S N2 Mechanistic Continuum in Glycosylation Reactions. J Am Chem Soc 2021; 143:1577-1589. [PMID: 33439656 PMCID: PMC8162065 DOI: 10.1021/jacs.0c12096] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
We report a computational approach to evaluate the reaction mechanisms of glycosylation using ab initio molecular dynamics (AIMD) simulations in explicit solvent. The reaction pathways are simulated via free energy calculations based on metadynamics and trajectory simulations using Born-Oppenheimer molecular dynamics. We applied this approach to investigate the mechanisms of the glycosylation of glucosyl α-trichloroacetimidate with three acceptors (EtOH, i-PrOH, and t-BuOH) in three solvents (ACN, DCM, and MTBE). The reactants and the solvents are treated explicitly using density functional theory. We show that the profile of the free energy surface, the synchronicity of the transition state structure, and the time gap between leaving group dissociation and nucleophile association can be used as three complementary indicators to describe the glycosylation mechanism within the SN1/SN2 continuum for a given reaction. This approach provides a reliable means to rationalize and predict reaction mechanisms and to estimate lifetimes of oxocarbenium intermediates and their dependence on the glycosyl donor, acceptor, and solvent environment.
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Affiliation(s)
- Yue Fu
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Leonardo Bernasconi
- Center for Research Computing, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Peng Liu
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
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23
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Tantillo DJ. Beyond transition state theory—Non-statistical dynamic effects for organic reactions. ADVANCES IN PHYSICAL ORGANIC CHEMISTRY 2021. [DOI: 10.1016/bs.apoc.2021.06.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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24
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Romi S, Fanetti S, Bini R. Accessing the Activation Mechanisms of Ethylene Photo-Polymerization under Pressure by Transient Infrared Absorption Spectroscopy. J Phys Chem B 2020; 124:8149-8157. [PMID: 32846090 DOI: 10.1021/acs.jpcb.0c06244] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The ambient temperature photoinduced polymerization of compressed (P < 1 GPa) fluid ethylene was characterized by transient infrared absorption spectroscopy with a resolution of few nanoseconds, 3 orders of magnitude higher than previously reported. The reaction has been studied under both one- and two-photon excitation evidencing in the latter case its occurrence only in the presence of different transition metal oxides. Their photocatalytic activity is ascribed to the stabilization of the excited biradicals through electron density exchange between the d orbitals of the metal and the π antibonding orbitals of ethylene which lengthens the lifetime of the biradicals. In both one- and two-photon activation cases the polymerization is characterized by an initial step distinguished by a molecularity of 0.15 ± 0.02 identified as the activation step of the reaction lasting, in the one-photon excitation case, a few hundreds of nanoseconds. Using pulsed excitation the reaction evolves toward a free radical polymerization only under one-photon excitation whereas the critical concentration of radicals required to propagate the reaction is never achieved in the two-photon excitation case. Comparison with continuous wave excitation unambiguously identifies in the average power released to the sample the key factor to drive quantitatively and qualitatively the polymerization.
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Affiliation(s)
- Sebastiano Romi
- LENS, European Laboratory for Non-linear Spectroscopy, Via N. Carrara 1, I-50019 Sesto Fiorentino, Firenze, Italy
| | - Samuele Fanetti
- LENS, European Laboratory for Non-linear Spectroscopy, Via N. Carrara 1, I-50019 Sesto Fiorentino, Firenze, Italy.,Istituto di Chimica dei Composti OrganoMetallici, ICCOM, Via Madonna del Piano 10, I-50019 Sesto Fiorentino, Firenze, Italy
| | - Roberto Bini
- LENS, European Laboratory for Non-linear Spectroscopy, Via N. Carrara 1, I-50019 Sesto Fiorentino, Firenze, Italy.,Istituto di Chimica dei Composti OrganoMetallici, ICCOM, Via Madonna del Piano 10, I-50019 Sesto Fiorentino, Firenze, Italy.,Dipartimento di Chimica "Ugo Schiff", Università di Firenze, Via della Lastruccia 3, I-50019 Sesto Fiorentino, Italy
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25
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Jonely M, Noriega R. Role of Polar Protic Solvents in the Dissociation and Reactivity of Photogenerated Radical Ion Pairs. J Phys Chem B 2020; 124:3083-3089. [PMID: 32239936 DOI: 10.1021/acs.jpcb.9b11299] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The UV photolysis of bimolecular charge transfer complexes is employed to yield reactive radical ions in their solvent-equilibrated electronic ground state. In polar protic media, noncovalent complexes of 1,2,4,5-tetracyanobenzene and toluene undergo efficient, ultrafast dissociation to ion pairs and equilibrate with their solvent environment before the resulting radical ions engage in electron transfer and proton abstraction on subnanosecond time scales. Solvent molecules play a critical role in these reactive pathways and in the dissociation and relaxation processes that precede them. We report a clear separation of time scales for these relaxation and reactive processes, which implies that solvent-solute interactions can be used as a tool for tuning the reaction pathways of equilibrated radical ions in solution.
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Affiliation(s)
- McKenzie Jonely
- Department of Chemistry, University of Utah, 315 S. 1400 E, Salt Lake City, Utah 84112, United States
| | - Rodrigo Noriega
- Department of Chemistry, University of Utah, 315 S. 1400 E, Salt Lake City, Utah 84112, United States
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26
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Yang Y, Zhang X, Zhong LP, Lan J, Li X, Li CC, Chung LW. Unusual KIE and dynamics effects in the Fe-catalyzed hetero-Diels-Alder reaction of unactivated aldehydes and dienes. Nat Commun 2020; 11:1850. [PMID: 32296076 PMCID: PMC7160212 DOI: 10.1038/s41467-020-15599-w] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 03/13/2020] [Indexed: 12/30/2022] Open
Abstract
Hetero-Diels-Alder (HDA) reaction is an important synthetic method for many natural products. An iron(III) catalyst was developed to catalyze the challenging HDA reaction of unactivated aldehydes and dienes with high selectivity. Here we report extensive density-functional theory (DFT) calculations and molecular dynamics simulations that show effects of iron (including its coordinate mode and/or spin state) on the dynamics of this reaction: considerably enhancing dynamically stepwise process, broadening entrance channel and narrowing exit channel from concerted asynchronous transition states. Also, our combined computational and experimental secondary KIE studies reveal unexpectedly large KIE values for the five-coordinate pathway even with considerable C-C bond forming, due to equilibrium isotope effect from the change in the metal coordination. Moreover, steric and electronic effects are computationally shown to dictate the C=O chemoselectivity for an α,β-unsaturated aldehyde, which is verified experimentally. Our mechanistic study may help design homogeneous, heterogeneous and biological catalysts for this challenging reaction.
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Affiliation(s)
- Yuhong Yang
- School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin, 150001, China
- Shenzhen Grubbs Institute, Department of Chemistry and Guangdong Provincial Key Laboratory of Catalytic Chemistry, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Xiaoyong Zhang
- Shenzhen Grubbs Institute, Department of Chemistry and Guangdong Provincial Key Laboratory of Catalytic Chemistry, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Li-Ping Zhong
- Shenzhen Grubbs Institute, Department of Chemistry and Guangdong Provincial Key Laboratory of Catalytic Chemistry, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Jialing Lan
- School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin, 150001, China
- Shenzhen Grubbs Institute, Department of Chemistry and Guangdong Provincial Key Laboratory of Catalytic Chemistry, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Xin Li
- Shenzhen Grubbs Institute, Department of Chemistry and Guangdong Provincial Key Laboratory of Catalytic Chemistry, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Chuang-Chuang Li
- Shenzhen Grubbs Institute, Department of Chemistry and Guangdong Provincial Key Laboratory of Catalytic Chemistry, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Lung Wa Chung
- Shenzhen Grubbs Institute, Department of Chemistry and Guangdong Provincial Key Laboratory of Catalytic Chemistry, Southern University of Science and Technology, Shenzhen, 518055, China.
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27
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Stable chaos and delayed onset of statisticality in unimolecular dissociation reactions. Commun Chem 2020; 3:4. [PMID: 36703308 PMCID: PMC9814671 DOI: 10.1038/s42004-019-0252-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 12/10/2019] [Indexed: 01/29/2023] Open
Abstract
Statistical models provide a powerful and useful class of approximations for calculating reaction rates by bypassing the need for detailed, and often difficult, dynamical considerations. Such approaches invariably invoke specific assumptions about the extent of intramolecular vibrational energy flow in the system. However, the nature of the transition to the statistical regime as a function of the molecular parameters is far from being completely understood. Here, we use tools from nonlinear dynamics to study the transition to statisticality in a model unimolecular reaction by explicitly visualizing the high dimensional classical phase space. We identify generic features in the phase space involving the intersection of two or more independent anharmonic resonances and show that the presence of correlated, but chaotic, intramolecular dynamics near such junctions leads to nonstatisticality. Interestingly, akin to the stability of asteroids in the Solar System, molecules can stay protected from dissociation at the junctions for several picoseconds due to the phenomenon of stable chaos.
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28
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Karmakar S, Keshavamurthy S. Intramolecular vibrational energy redistribution and the quantum ergodicity transition: a phase space perspective. Phys Chem Chem Phys 2020; 22:11139-11173. [DOI: 10.1039/d0cp01413c] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The onset of facile intramolecular vibrational energy flow can be related to features in the connected network of anharmonic resonances in the classical phase space.
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Affiliation(s)
- Sourav Karmakar
- Department of Chemistry
- Indian Institute of Technology
- Kanpur
- India
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29
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Govindarajan N, Meijer EJ. Elucidating cation effects in homogeneously catalyzed formic acid dehydrogenation. Faraday Discuss 2019; 220:404-413. [PMID: 31544196 DOI: 10.1039/c9fd00055k] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this work, we use density functional theory based molecular dynamics with an explicit description of methanol solvent to study the effect of cations on formic acid dehydrogenation catalyzed by a ruthenium PNP pincer complex (RuPNP). Formic acid dehydrogenation is a two step process that involves the reorientation of the formate moiety bound via its oxygen to a H bound intermediate, followed by the hydride transfer step to form CO2 and the hydrogenated catalyst. We find the reorientation step to proceed with a low barrier in methanol solvent and in the presence of a Li+ cation, while the hydride transfer is significantly hindered by the presence of cations (Li+ and K+). The cation seems to strongly stabilize the negatively charged formate moiety, hindering complete hydride transfer and resulting in a high barrier for this step. This study is a first step towards addressing the exact role of cations in formic acid dehydrogenation reactions.
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Affiliation(s)
- Nitish Govindarajan
- Van't Hoff Institute for Molecular Sciences, Amsterdam Center for Multiscale Modeling, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands.
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30
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Mao Y, Montoya-Castillo A, Markland TE. Accurate and efficient DFT-based diabatization for hole and electron transfer using absolutely localized molecular orbitals. J Chem Phys 2019; 151:164114. [DOI: 10.1063/1.5125275] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Affiliation(s)
- Yuezhi Mao
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
| | | | - Thomas E. Markland
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
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31
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Harvey JN, Himo F, Maseras F, Perrin L. Scope and Challenge of Computational Methods for Studying Mechanism and Reactivity in Homogeneous Catalysis. ACS Catal 2019. [DOI: 10.1021/acscatal.9b01537] [Citation(s) in RCA: 106] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Jeremy N. Harvey
- Department of Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Fahmi Himo
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Feliu Maseras
- Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology, Avgda. Països Catalans, 16, 43007 Tarragona, Catalonia, Spain
| | - Lionel Perrin
- Univ Lyon, Université Claude Bernard Lyon 1, CPE Lyon, INSA Lyon, ICBMS, CNRS UMR 5246, 43 Bd. du 11 Novembre 1918, 69622 Villeurbanne, France
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32
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Otolski CJ, Mohan Raj A, Sharma G, Prabhakar R, Ramamurthy V, Elles CG. Ultrafast trans → cis Photoisomerization Dynamics of Alkyl-Substituted Stilbenes in a Supramolecular Capsule. J Phys Chem A 2019; 123:5061-5071. [PMID: 31140802 DOI: 10.1021/acs.jpca.9b03285] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Ultrafast spectroscopy reveals the effects of confinement on the excited-state photoisomerization dynamics for a series of alkyl-substituted trans-stilbenes encapsulated in the hydrophobic cavity of an aqueous supramolecular organic host-guest complex. Compared with the solvated compounds, encapsulated trans-stilbenes have broader excited-state absorption spectra, excited-state lifetimes that are 3-4 times longer, and photoisomerization quantum yields that are 1.7-6.5 times lower in the restricted environment. The organic capsule disrupts the equilibrium structure and restricts torsional rotation around the central C═C double bond in the excited state, which is an important motion for the relaxation of trans-stilbene from S1 to S0. The location and identity of alkyl substituents play a significant role in determining the excited-state dynamics and photoisomerization quantum yields by tuning the relative crowding inside the capsule. The results are discussed in terms of distortions of the ground- and excited-state potential energy surfaces, including the topology of the S1-S0 conical intersection.
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Affiliation(s)
- Christopher J Otolski
- Department of Chemistry , University of Kansas , Lawrence , Kansas 66045 , United States
| | - A Mohan Raj
- Department of Chemistry , University of Miami , Coral Gables , Florida 33146 , United States
| | - Gaurav Sharma
- Department of Chemistry , University of Miami , Coral Gables , Florida 33146 , United States
| | - Rajeev Prabhakar
- Department of Chemistry , University of Miami , Coral Gables , Florida 33146 , United States
| | | | - Christopher G Elles
- Department of Chemistry , University of Kansas , Lawrence , Kansas 66045 , United States
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33
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Balevičius V, Wei T, Di Tommaso D, Abramavicius D, Hauer J, Polívka T, Duffy CDP. The full dynamics of energy relaxation in large organic molecules: from photo-excitation to solvent heating. Chem Sci 2019; 10:4792-4804. [PMID: 31183032 PMCID: PMC6521204 DOI: 10.1039/c9sc00410f] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 03/29/2019] [Indexed: 01/04/2023] Open
Abstract
In some molecular systems, such as nucleobases, polyenes or sunscreens, substantial amounts of photo-excitation energy are dissipated on a sub-picosecond time scale. Where does this energy go or among which degrees of freedom it is being distributed at such early times?
In some molecular systems, such as nucleobases, polyenes or the active ingredients of sunscreens, substantial amounts of photo-excitation energy are dissipated on a sub-picosecond time scale, raising questions such as: where does this energy go or among which degrees of freedom it is being distributed at such early times? Here we use transient absorption spectroscopy to track excitation energy dispersing from the optically accessible vibronic subsystem into the remaining vibrational subsystem of the solute and solvent. Monitoring the flow of energy during vibrational redistribution enables quantification of local molecular heating. Subsequent heat dissipation away from the solute molecule is characterized by classical thermodynamics and molecular dynamics simulations. Hence, we present a holistic approach that tracks the internal temperature and vibronic distribution from the act of photo-excitation to the restoration of the global equilibrium. Within this framework internal vibrational redistribution and vibrational cooling are emergent phenomena. We demonstrate the validity of the framework by examining a highly controversial example, carotenoids. We show that correctly accounting for the local temperature unambiguously explains their energetically and temporally congested spectral dynamics without the ad hoc postulation of additional ‘dark’ states. An immediate further application of this approach would be to monitor the excitation and thermal dynamics of pigment–protein systems.
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Affiliation(s)
- Vytautas Balevičius
- School of Chemical and Biological Sciences , Queen Mary University of London , Mile End Road , London E1 4NS , UK .
| | - Tiejun Wei
- School of Chemical and Biological Sciences , Queen Mary University of London , Mile End Road , London E1 4NS , UK .
| | - Devis Di Tommaso
- School of Chemical and Biological Sciences , Queen Mary University of London , Mile End Road , London E1 4NS , UK .
| | - Darius Abramavicius
- Institute of Chemical Physics , Vilnius University , Sauletekio av. 9 , Vilnius , LT-10222 , Lithuania
| | - Jürgen Hauer
- Fakultät für Chemie , Technical University of Munich , Lichtenbergstraße 4 , D-85748 Garching , Germany.,Photonics Institute , TU Wien , Gußhausstraße 27 , 1040 Vienna , Austria
| | - Tomas Polívka
- Institute of Physics and Biophysics , Faculty of Science , University of South Bohemia , Branišovská 1760 , 37005 České Budějovice , Czech Republic
| | - Christopher D P Duffy
- School of Chemical and Biological Sciences , Queen Mary University of London , Mile End Road , London E1 4NS , UK .
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34
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Yang Z, Jamieson CS, Xue XS, Garcia-Borràs M, Benton T, Dong X, Liu F, Houk K. Mechanisms and Dynamics of Reactions Involving Entropic Intermediates. TRENDS IN CHEMISTRY 2019. [DOI: 10.1016/j.trechm.2019.01.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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35
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Zhao Z, Bababrik R, Xue W, Li Y, Briggs NM, Nguyen DT, Nguyen U, Crossley SP, Wang S, Wang B, Resasco DE. Solvent-mediated charge separation drives alternative hydrogenation path of furanics in liquid water. Nat Catal 2019. [DOI: 10.1038/s41929-019-0257-z] [Citation(s) in RCA: 102] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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36
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Corona-González MV, Zamora-Moreno J, Muñoz-Hernández MA, Vendier L, Sabo-Etienne S, Montiel-Palma V. Exploiting the Versatility of Phosphinobenzylsilanes for the Stabilization of 14-Electron Rhodium(III) and Iridium(III) Complexes. Eur J Inorg Chem 2019. [DOI: 10.1002/ejic.201900107] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- María Vicky Corona-González
- Centro de Investigaciones Químicas; IICBA; Universidad Autónoma del Estado de Morelos; Avenida Universidad 1001, Col. Chamilpa 62209 Cuernavaca, Morelos, C. P. Mexico
- LCC-CNRS; IICBA; Université de Toulouse, CNRS, UPS; 205 route de Narbonne, BP 44099 31077 Toulouse Cedex 4 France
| | - Julio Zamora-Moreno
- Centro de Investigaciones Químicas; IICBA; Universidad Autónoma del Estado de Morelos; Avenida Universidad 1001, Col. Chamilpa 62209 Cuernavaca, Morelos, C. P. Mexico
| | - Miguel A. Muñoz-Hernández
- Centro de Investigaciones Químicas; IICBA; Universidad Autónoma del Estado de Morelos; Avenida Universidad 1001, Col. Chamilpa 62209 Cuernavaca, Morelos, C. P. Mexico
| | - Laure Vendier
- LCC-CNRS; IICBA; Université de Toulouse, CNRS, UPS; 205 route de Narbonne, BP 44099 31077 Toulouse Cedex 4 France
| | - Sylviane Sabo-Etienne
- LCC-CNRS; IICBA; Université de Toulouse, CNRS, UPS; 205 route de Narbonne, BP 44099 31077 Toulouse Cedex 4 France
| | - Virginia Montiel-Palma
- Centro de Investigaciones Químicas; IICBA; Universidad Autónoma del Estado de Morelos; Avenida Universidad 1001, Col. Chamilpa 62209 Cuernavaca, Morelos, C. P. Mexico
- Department of Chemistry; IICBA; Mississippi State University; Box 9573 39762 Mississippi State Mississippi USA
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37
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Lee YM, Kim S, Ohkubo K, Kim KH, Nam W, Fukuzumi S. Unified Mechanism of Oxygen Atom Transfer and Hydrogen Atom Transfer Reactions with a Triflic Acid-Bound Nonheme Manganese(IV)-Oxo Complex via Outer-Sphere Electron Transfer. J Am Chem Soc 2019; 141:2614-2622. [PMID: 30646680 DOI: 10.1021/jacs.8b12935] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Outer-sphere electron transfer from styrene, thioanisole, and toluene derivatives to a triflic acid (HOTf)-bound nonheme Mn(IV)-oxo complex, [(N4Py)MnIV(O)]2+-(HOTf)2 (N4Py = N, N-bis(2-pyridylmethyl)- N-bis(2-pyridyl)methylamine), has been shown to be the rate-determining step of different types of redox reactions such as epoxidation, sulfoxidation, and hydroxylation of styrene, thioanisole, and toluene derivatives, respectively, by [(N4Py)MnIV(O)]2+-(HOTf)2. The rate constants of HOTf-promoted epoxidation of all styrene derivatives with [(N4Py)MnIV(O)]2+ and electron transfer from electron donors to [(N4Py)MnV(O)]2+ exhibit a remarkably unified correlation with the driving force of outer-sphere electron transfer in light of the Marcus theory of electron transfer. The same electron-transfer driving force dependence is observed in the oxygen atom transfer from [(N4Py)MnIV(O)]2+-(HOTf)2 to thioanisole derivatives as well as in the hydrogen atom transfer from toluene derivatives to [(N4Py)MnIV(O)]2+-(HOTf)2. Thus, mechanisms of oxygen atom transfer (epoxidation and sulfoxidation) reactions of styrene and thioanisole derivatives and hydrogen atom transfer (hydroxylation) reactions of toluene derivatives by [(N4Py)MnIV(O)]2+-(HOTf)2 have been unified for the first time as the same reaction pathway via outer-sphere electron transfer, followed by the fast bond-forming step, which exhibits the singly unified electron-transfer driving force dependence of the rate constants as outer-sphere electron-transfer reactions. In the case of the epoxidation of cis-stilbene by [(N4Py)MnIV(O)]2+-(HOTf)2, the isomerization of cis-stilbene radical cation to trans-stilbene radical cation occurs after outer-sphere electron transfer from cis-stilbene to [(N4Py)MnIV(O)]2+-(HOTf)2 to yield trans-stilbene oxide selectively, which is also taken as evidence for the occurrence of electron transfer in the acid-catalyzed epoxidation.
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Affiliation(s)
- Yong-Min Lee
- Department of Chemistry and Nano Science , Ewha Womans University , Seoul 03760 , Korea
| | - Surin Kim
- Department of Chemistry and Nano Science , Ewha Womans University , Seoul 03760 , Korea
| | - Kei Ohkubo
- Institute for Advanced Co-Creation Studies, Open and Transdisciplinary Research Initiatives , Osaka University , Suita , Osaka 565-0871 , Japan
| | - Kyung-Ha Kim
- Department of Chemistry and Nano Science , Ewha Womans University , Seoul 03760 , Korea
| | - Wonwoo Nam
- Department of Chemistry and Nano Science , Ewha Womans University , Seoul 03760 , Korea.,State Key Laboratory for Oxo Synthesis and Selective Oxidation, Suzhou Research Institute of LICP, Lanzhou Institute of Chemical Physics (LICP), Chinese Academy of Sciences , Lanzhou 730000 , China
| | - Shunichi Fukuzumi
- Department of Chemistry and Nano Science , Ewha Womans University , Seoul 03760 , Korea.,Faculty of Science and Engineering , Meijo University , SENTAN, Japan Science and Technology Agency (JST), Nagoya , Aichi 468-0073 , Japan
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38
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Nikitin K, O'Gara R. Mechanisms and Beyond: Elucidation of Fluxional Dynamics by Exchange NMR Spectroscopy. Chemistry 2019; 25:4551-4589. [PMID: 30421834 DOI: 10.1002/chem.201804123] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2018] [Indexed: 12/31/2022]
Abstract
Detailed mechanistic information is crucial to our understanding of reaction pathways and selectivity. Dynamic exchange NMR techniques, in particular 2D exchange spectroscopy (EXSY) and its modifications, provide indispensable intricate information on the mechanisms of organic and inorganic reactions and other phenomena, for example, the dynamics of interfacial processes. In this Review, key results from exchange NMR studies of small molecules over the last few decades are systemised and discussed. After a brief introduction to the theory, the key types of dynamic processes are identified and fundamental examples given of intra- and intermolecular reactions, which, in turn, could involve, or not, bond-making and bond-breaking events. Following that logic, internal molecular rotation, intramolecular stereomutation and molecular recognition will first be considered because they do not typically involve bond breaking. Then, rearrangements, substitution-type reactions, cyclisations, additions and other processes affecting chemical bonds will be discussed. Finally, interfacial molecular dynamics and unexpected combinations of different types of fluxional processes will also be highlighted. How exchange NMR spectroscopy helps to identify conformational changes, coordination and molecular recognition processes as well as quantify reaction energy barriers and extract detailed mechanistic information by using reaction rate theory in conjunction with computational techniques will be shown.
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Affiliation(s)
- Kirill Nikitin
- School of Chemistry, University College Dublin, Belfield, Dublin, Ireland
| | - Ryan O'Gara
- School of Chemistry, University College Dublin, Belfield, Dublin, Ireland
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39
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Fehér PP, Stirling A. Assessment of reactivities with explicit and implicit solvent models: QM/MM and gas-phase evaluation of three different Ag-catalysed furan ring formation routes. NEW J CHEM 2019. [DOI: 10.1039/c9nj04003j] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A representative reaction illustrates cases where strong solvent–solute interactions can be sufficiently well captured by continuum solvation model rendering QM/MM unnecessary.
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Affiliation(s)
- Péter Pál Fehér
- Research Center for Natural Sciences
- Hungarian Academy of Sciences
- Budapest
- Hungary
| | - András Stirling
- Research Center for Natural Sciences
- Hungarian Academy of Sciences
- Budapest
- Hungary
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40
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Zhang X, Harvey JN. EVB and polarizable MM study of energy relaxation in fluorine–acetonitrile reactions. Phys Chem Chem Phys 2019; 21:14331-14340. [DOI: 10.1039/c8cp06686h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Many-body effects can impact on rates of energy transfer from a ‘hot’ DF solute to acetonitrile solvent.
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Affiliation(s)
- Xiaoyong Zhang
- Department of Chemistry and Division of Quantum Chemistry and Physical Chemistry
- KU Leuven
- B-3001 Leuven
- Belgium
| | - Jeremy N. Harvey
- Department of Chemistry and Division of Quantum Chemistry and Physical Chemistry
- KU Leuven
- B-3001 Leuven
- Belgium
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41
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Hare SR, Li A, Tantillo DJ. Post-transition state bifurcations induce dynamical detours in Pummerer-like reactions. Chem Sci 2018; 9:8937-8945. [PMID: 30627409 PMCID: PMC6296359 DOI: 10.1039/c8sc02653j] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2018] [Accepted: 09/25/2018] [Indexed: 12/28/2022] Open
Abstract
A post-transition state bifurcation (PTSB) involved in a Pummerer-type rearrangement is characterized using density functional theory (DFT) calculations on potential energy stationary points and direct dynamics simulations. A sensitivity of the ratio of products produced via this PTSB to solvent dielectric constant is revealed and implications of such a dependence for selectivity control of organic reactions are discussed.
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Affiliation(s)
| | - Ang Li
- Shanghai Institute of Organic Chemistry , China
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42
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Karmakar S, Keshavamurthy S. Relevance of the Resonance Junctions on the Arnold Web to Dynamical Tunneling and Eigenstate Delocalization. J Phys Chem A 2018; 122:8636-8649. [PMID: 30289718 DOI: 10.1021/acs.jpca.8b08626] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We study the competition and correspondence between the classical and quantum routes to intramolecular vibrational energy redistribution (IVR) in a three degrees of freedom model effective Hamiltonian. Specifically, we focus on the classical and the quantum dynamics near the resonance junctions on the Arnold web that are formed by an intersection of independent resonances. The regime of interest models the IVR dynamics from highly excited initial states near dissociation thresholds of molecular systems wherein both classical and purely quantum, involving dynamical tunneling, routes to IVR coexist. In the vicinity of a resonance junction, classical chaos is inevitably present, and hence one expects the quantum IVR pathways to have a strong classical component as well. We show that with increasing resonant coupling strengths the classical component of IVR leads to a transition from coherent dynamical tunneling to incoherent dynamical tunneling. Furthermore, we establish that the quantum IVR dynamics can be predicted based on the structures on the classical Arnold web. In addition, we investigate the nature of the highly excited eigenstates to identify the quantum signatures of the multiplicity-2 junctions. For the parameter regimes studies herein, by projecting the eigenstates onto the Arnold web, we find that eigenstates in the vicinity of the junctions are primarily delocalized due to dynamical tunneling.
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Affiliation(s)
- Sourav Karmakar
- Department of Chemistry , Indian Institute of Technology , Kanpur , Uttar Pradesh 208 016 , India
| | - Srihari Keshavamurthy
- Department of Chemistry , Indian Institute of Technology , Kanpur , Uttar Pradesh 208 016 , India
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43
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dos Passos Gomes G, Morrison AE, Dudley GB, Alabugin IV. Optimizing Amine‐Mediated Alkyne–Allene Isomerization to Improve Benzannulation Cascades: Synergy between Theory and Experiments. European J Org Chem 2018. [DOI: 10.1002/ejoc.201801052] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
| | - Alec E. Morrison
- Department of Chemistry and Biochemistry Florida State University 32306 Tallahassee FL USA
| | - Gregory B. Dudley
- C. Eugene Bennett Department of Chemistry West Virginia University 26505 Morgantown WV USA
| | - Igor V. Alabugin
- Department of Chemistry and Biochemistry Florida State University 32306 Tallahassee FL USA
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44
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Stabilizing the Meniscus for Operando Characterization of Platinum During the Electrolyte-Consuming Alkaline Oxygen Evolution Reaction. Top Catal 2018. [DOI: 10.1007/s11244-018-1063-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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45
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Proppe J, Husch T, Simm GN, Reiher M. Uncertainty quantification for quantum chemical models of complex reaction networks. Faraday Discuss 2018; 195:497-520. [PMID: 27730243 DOI: 10.1039/c6fd00144k] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
For the quantitative understanding of complex chemical reaction mechanisms, it is, in general, necessary to accurately determine the corresponding free energy surface and to solve the resulting continuous-time reaction rate equations for a continuous state space. For a general (complex) reaction network, it is computationally hard to fulfill these two requirements. However, it is possible to approximately address these challenges in a physically consistent way. On the one hand, it may be sufficient to consider approximate free energies if a reliable uncertainty measure can be provided. On the other hand, a highly resolved time evolution may not be necessary to still determine quantitative fluxes in a reaction network if one is interested in specific time scales. In this paper, we present discrete-time kinetic simulations in discrete state space taking free energy uncertainties into account. The method builds upon thermo-chemical data obtained from electronic structure calculations in a condensed-phase model. Our kinetic approach supports the analysis of general reaction networks spanning multiple time scales, which is here demonstrated for the example of the formose reaction. An important application of our approach is the detection of regions in a reaction network which require further investigation, given the uncertainties introduced by both approximate electronic structure methods and kinetic models. Such cases can then be studied in greater detail with more sophisticated first-principles calculations and kinetic simulations.
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Affiliation(s)
- Jonny Proppe
- Laboratory of Physical Chemistry, ETH Zürich, Zürich, Switzerland.
| | - Tamara Husch
- Laboratory of Physical Chemistry, ETH Zürich, Zürich, Switzerland.
| | - Gregor N Simm
- Laboratory of Physical Chemistry, ETH Zürich, Zürich, Switzerland.
| | - Markus Reiher
- Laboratory of Physical Chemistry, ETH Zürich, Zürich, Switzerland.
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46
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Geng C, Li J, Weiske T, Schwarz H. Thermal O–H Bond Activation of Water As Mediated by Heteronuclear [Al2Mg2O5]•+: Evidence for Oxygen-Atom Scrambling. J Am Chem Soc 2018; 140:9275-9281. [DOI: 10.1021/jacs.8b05618] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Caiyun Geng
- Institut für Chemie, Technische Universität Berlin, Straße des 17 Juni 115, Berlin 10623, Germany
| | - Jilai Li
- Institut für Chemie, Technische Universität Berlin, Straße des 17 Juni 115, Berlin 10623, Germany
- Institute of Theoretical Chemistry, Jilin University, Changchun 130023, People’s Republic of China
| | - Thomas Weiske
- Institut für Chemie, Technische Universität Berlin, Straße des 17 Juni 115, Berlin 10623, Germany
| | - Helmut Schwarz
- Institut für Chemie, Technische Universität Berlin, Straße des 17 Juni 115, Berlin 10623, Germany
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47
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Besora M, Maseras F. Microkinetic modeling in homogeneous catalysis. WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE 2018. [DOI: 10.1002/wcms.1372] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Maria Besora
- Institute of Chemical Research of Catalonia (ICIQ)Barcelona Institute of Science and TechnologyBarcelonaSpain
| | - Feliu Maseras
- Institute of Chemical Research of Catalonia (ICIQ)Barcelona Institute of Science and TechnologyBarcelonaSpain
- Departament de QuímicaUniversitat Autònoma de Barcelona (UAB)BarcelonaSpain
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48
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Tan JSJ, Hirvonen V, Paton RS. Dynamic Intermediates in the Radical Cation Diels–Alder Cycloaddition: Lifetime and Suprafacial Stereoselectivity. Org Lett 2018; 20:2821-2825. [DOI: 10.1021/acs.orglett.8b00737] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jacqueline S. J. Tan
- Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, U.K
| | - Viivi Hirvonen
- Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, U.K
| | - Robert S. Paton
- Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, U.K
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
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49
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Essafi S, Harvey JN. Rates of Molecular Vibrational Energy Transfer in Organic Solutions. J Phys Chem A 2018; 122:3535-3540. [DOI: 10.1021/acs.jpca.7b12563] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Stéphanie Essafi
- School of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, United Kingdom
| | - Jeremy N. Harvey
- School of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, United Kingdom
- Department of Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
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50
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Yang Z, Houk KN. The Dynamics of Chemical Reactions: Atomistic Visualizations of Organic Reactions, and Homage to van ’t Hoff. Chemistry 2018. [DOI: 10.1002/chem.201706032] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Zhongyue Yang
- Department of Chemistry and Biochemistry; University of California; Los Angeles California 90095 USA
| | - K. N. Houk
- Department of Chemistry and Biochemistry; University of California; Los Angeles California 90095 USA
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