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Schleif T, Prado Merini M, Henkel S, Sander W. Solvation Effects on Quantum Tunneling Reactions. Acc Chem Res 2022; 55:2180-2190. [PMID: 35730754 DOI: 10.1021/acs.accounts.2c00151] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
A decisive factor for obtaining high yields and selectivities in organic synthesis is the choice of the proper solvent. Solvent selection is often guided by the intuitive understanding of transition state-solvent interactions. However, quantum-mechanical tunneling can significantly contribute to chemical reactions, circumventing the transition state and thus depriving chemists of their intuitive handle on the reaction kinetics. In this Account, we aim to provide rationales for the effects of solvation on tunneling reactions derived from experiments performed in cryogenic matrices.The tunneling reactions analyzed here cover a broad range of prototypical organic transformations that are subject to strong solvation effects. Examples are the hydrogen tunneling probability for the cis-trans isomerization of formic acid which is strongly reduced upon formation of hydrogen-bonded complexes and the [1,2]H-shift in methylhydroxycarbene where a change in product selectivity is predicted upon interaction with hydrogen bond acceptors.Not only hydrogen but also heavy atom tunneling can exhibit strong solvent effects. The direction of the nearly degenerate valence tautomerization between benzene oxide and oxepin was found to reverse upon formation of a halogen or hydrogen bond with ICF3 or H2O. But even in the absence of strong noncovalent interactions such as hydrogen or halogen bonding, solvation can have a decisive effect on tunneling as evidenced by the Cope rearrangement of semibullvalenes via heavy-atom tunneling. Can quantum tunneling be catalyzed? The acceleration of the ring expansion of 1H-bicyclo[3.1.0.]-hexa-3,5-dien-2-one by complexation with Lewis acids provides a proof-of-concept for tunneling catalysis.Two concepts are central for the explanation and prediction of solvation effects on tunneling phenomena: a simple approach expands the Born-Oppenheimer approximation by separating nuclear degrees of freedom into intra- and intermolecular degrees. Intermolecular movements represent the slowest motions within molecular aggregates, thus effectively freezing the position of the solvent in relation to the reactant during the tunneling process. Another useful approach is to treat reactants and products by separate single-well potentials, where the intersection represents the transition state. Thus, stabilization of the reactants via solvation should result in an increase in barrier heights and widths which in turn lowers tunneling probabilities. These simple models can predict trends in tunneling kinetics and provide a rational basis for controlling tunneling reactions via solvation.
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Affiliation(s)
- Tim Schleif
- Lehrstuhl für Organische Chemie II, Ruhr-Universität Bochum, 44801 Bochum, Germany
| | - Melania Prado Merini
- Lehrstuhl für Organische Chemie II, Ruhr-Universität Bochum, 44801 Bochum, Germany
| | - Stefan Henkel
- Lehrstuhl für Organische Chemie II, Ruhr-Universität Bochum, 44801 Bochum, Germany
| | - Wolfram Sander
- Lehrstuhl für Organische Chemie II, Ruhr-Universität Bochum, 44801 Bochum, Germany
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Vermeeren P, Dalla Tiezza M, Wolf ME, Lahm ME, Allen WD, Schaefer HF, Hamlin TA, Bickelhaupt FM. Pericyclic reaction benchmarks: hierarchical computations targeting CCSDT(Q)/CBS and analysis of DFT performance. Phys Chem Chem Phys 2022; 24:18028-18042. [PMID: 35861164 PMCID: PMC9348522 DOI: 10.1039/d2cp02234f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 07/07/2022] [Indexed: 11/21/2022]
Abstract
Hierarchical, convergent ab initio benchmark computations were performed followed by a systematic analysis of DFT performance for five pericyclic reactions comprising Diels-Alder, 1,3-dipolar cycloaddition, electrocyclic rearrangement, sigmatropic rearrangement, and double group transfer prototypes. Focal point analyses (FPA) extrapolating to the ab initio limit were executed via explicit quantum chemical computations with electron correlation treatments through CCSDT(Q) and correlation-consistent Gaussian basis sets up to aug'-cc-pV5Z. Optimized geometric structures and vibrational frequencies of all stationary points were obtained at the CCSD(T)/cc-pVTZ level of theory. The FPA reaction barriers and energies exhibit convergence to within a few tenths of a kcal mol-1. The FPA benchmarks were used to evaluate the performance of 60 density functionals (eight dispersion-corrected), covering the local-density approximation (LDA), generalized gradient approximations (GGAs), meta-GGAs, hybrids, meta-hybrids, double-hybrids, and range-separated hybrids. The meta-hybrid M06-2X functional provided the best overall performance [mean absolute error (MAE) of 1.1 kcal mol-1] followed closely by the double-hybrids B2K-PLYP, mPW2K-PLYP, and revDSD-PBEP86 [MAE of 1.4-1.5 kcal mol-1]. The regularly used GGA functional BP86 gave a higher MAE of 5.8 kcal mol-1, but it qualitatively described the trends in reaction barriers and energies. Importantly, we established that accurate yet efficient meta-hybrid or double-hybrid DFT potential energy surfaces can be acquired based on geometries from the computationally efficient and robust BP86/DZP level.
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Affiliation(s)
- Pascal Vermeeren
- Department of Theoretical Chemistry, Amsterdam Institute of Molecular and Life Sciences (AIMMS), Amsterdam Center for Multiscale Modeling (ACMM), Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands.
| | - Marco Dalla Tiezza
- Department of Theoretical Chemistry, Amsterdam Institute of Molecular and Life Sciences (AIMMS), Amsterdam Center for Multiscale Modeling (ACMM), Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands.
| | - Mark E Wolf
- Center for Computational Quantum Chemistry, University of Georgia, Athens, GA 30602, USA.
| | - Mitchell E Lahm
- Center for Computational Quantum Chemistry, University of Georgia, Athens, GA 30602, USA.
| | - Wesley D Allen
- Center for Computational Quantum Chemistry, University of Georgia, Athens, GA 30602, USA.
- Allen Heritage Foundation, Dickson, TN 37055, USA
| | - Henry F Schaefer
- Center for Computational Quantum Chemistry, University of Georgia, Athens, GA 30602, USA.
| | - Trevor A Hamlin
- Department of Theoretical Chemistry, Amsterdam Institute of Molecular and Life Sciences (AIMMS), Amsterdam Center for Multiscale Modeling (ACMM), Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands.
| | - F Matthias Bickelhaupt
- Department of Theoretical Chemistry, Amsterdam Institute of Molecular and Life Sciences (AIMMS), Amsterdam Center for Multiscale Modeling (ACMM), Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands.
- Institute for Molecules and Materials (IMM), Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
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Bernhardt B, Ruth M, Reisenauer HP, Schreiner PR. Aminohydroxymethylene (H 2N-C̈-OH), the Simplest Aminooxycarbene. J Phys Chem A 2021; 125:7023-7028. [PMID: 34374543 DOI: 10.1021/acs.jpca.1c06151] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We generated and isolated hitherto unreported aminohydroxymethylene (1, aminohydroxycarbene) in solid Ar via pyrolysis of oxalic acid monoamide (2). Astrochemically relevant carbene 1 is persistent under cryogenic conditions and only decomposes to HNCO + H2 and NH3 + CO upon irradiation of the matrix at 254 nm. This photoreactivity is contrary to other hydroxycarbenes and aminomethylene, which undergo [1,2]H shifts to the corresponding carbonyls or imine. The experimental data are well supported by the results of CCSD(T)/cc-pVTZ and B3LYP/6-311++G(3df,3pd) computations.
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Affiliation(s)
- Bastian Bernhardt
- Institute of Organic Chemistry, Justus Liebig University, Heinrich-Buff-Ring 17, 35392 Giessen, Germany
| | - Marcel Ruth
- Institute of Organic Chemistry, Justus Liebig University, Heinrich-Buff-Ring 17, 35392 Giessen, Germany
| | - Hans Peter Reisenauer
- Institute of Organic Chemistry, Justus Liebig University, Heinrich-Buff-Ring 17, 35392 Giessen, Germany
| | - Peter R Schreiner
- Institute of Organic Chemistry, Justus Liebig University, Heinrich-Buff-Ring 17, 35392 Giessen, Germany
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Bernhardt B, Ruth M, Eckhardt AK, Schreiner PR. Ethynylhydroxycarbene (H-C≡C-C̈-OH). J Am Chem Soc 2021; 143:3741-3746. [PMID: 33667077 DOI: 10.1021/jacs.1c00897] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The species on the C3H2O potential energy surface have long been known to play a vital role in extraterrestrial chemistry. Here we report on the hitherto uncharacterized isomer ethynylhydroxycarbene (H-C≡C-C̈-OH, 1) generated by high-vacuum flash pyrolysis of ethynylglyoxylic acid ethyl ester and trapped in solid argon matrices at 3 and 20 K. Upon irradiation at 436 nm trans-1 rearranges to its higher lying cis-conformer. Prolonged irradiation leads to the formation of propynal. When the matrix is kept in the dark, 1 reacts within a half-life of ca. 70 h to propynal in a conformer-specific [1,2]H-tunneling process. Our results are fully consistent with computations at the CCSD(T)/cc-pVTZ and the B3LYP/def2-QZVPP levels of theory.
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Affiliation(s)
- Bastian Bernhardt
- Institute of Organic Chemistry, Justus Liebig University Giessen, Heinrich-Buff-Ring 17, 35392 Giessen, Germany
| | - Marcel Ruth
- Institute of Organic Chemistry, Justus Liebig University Giessen, Heinrich-Buff-Ring 17, 35392 Giessen, Germany
| | - André K Eckhardt
- Institute of Organic Chemistry, Justus Liebig University Giessen, Heinrich-Buff-Ring 17, 35392 Giessen, Germany
| | - Peter R Schreiner
- Institute of Organic Chemistry, Justus Liebig University Giessen, Heinrich-Buff-Ring 17, 35392 Giessen, Germany
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