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Arandhara M, Ramesh SG. Nuclear quantum effects in gas-phase 2-fluoroethanol. Phys Chem Chem Phys 2024; 26:6885-6902. [PMID: 38333949 DOI: 10.1039/d3cp05657k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2024]
Abstract
Torsional motions along the FCCO and HOCC dihedrals lead to the five unique conformations of 2-fluoroethanol, of which the conformer that is gauche along both dihedrals has the lowest energy. In this work, we explore how nuclear quantum effects (NQEs) manifest in the structural parameters of the lowest energy conformer, in the intramolecular free energy landscape along the FCCO and HOCC dihedrals, and also in the infrared spectrum of the title molecule, through the use of path integral simulations. We have first developed a full dimensional potential energy surface using the reaction surface Hamiltonian framework. On this potential, we have carried out path integral molecular dynamics simulations at several temperatures starting from the minimum energy well to explore structural influences of NQEs including geometrical markers of the interaction between the OH and F groups. From the computed free energy landscapes, significant reduction of the torsional barrier is found at low temperature near the cis region of the dihedrals, which can be understood through the trends in the radii of gyration of the atomic ring polymers. We find that the inclusion of NQEs in the computation of infrared spectrum is important to obtain good agreement with the experimental band positions.
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Affiliation(s)
- Mrinal Arandhara
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560012, India.
| | - Sai G Ramesh
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560012, India.
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2
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Del Vigo EA, Marino C, Stortz CA. Exhaustive rotamer search of the 4C1 conformation of α- and β-d-galactopyranose. Carbohydr Res 2017; 448:136-147. [DOI: 10.1016/j.carres.2017.05.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 04/03/2017] [Accepted: 05/05/2017] [Indexed: 10/19/2022]
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Lonardi A, Oborský P, Hünenberger PH. Solvent-Modulated Influence of Intramolecular Hydrogen-Bonding on the Conformational Properties of the Hydroxymethyl Group in Glucose and Galactose: A Molecular Dynamics Simulation Study. Helv Chim Acta 2016. [DOI: 10.1002/hlca.201600158] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Alice Lonardi
- Laboratory of Physical Chemistry; ETH Hönggerberg; HCI; CH-8093 Zürich Switzerland
| | - Pavel Oborský
- Laboratory of Physical Chemistry; ETH Hönggerberg; HCI; CH-8093 Zürich Switzerland
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Brauer B, Pincu M, Buch V, Bar I, Simons JP, Gerber RB. Vibrational Spectra of α-Glucose, β-Glucose, and Sucrose: Anharmonic Calculations and Experiment. J Phys Chem A 2011; 115:5859-72. [DOI: 10.1021/jp110043k] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Brina Brauer
- Institute of Chemistry and The Fritz Haber Research Center, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel
| | - Madeleine Pincu
- Department of Chemistry, University of California, Irvine, California 92697, United States
| | - Victoria Buch
- Institute of Chemistry and The Fritz Haber Research Center, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel
| | - Ilana Bar
- Department of Physics, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel
| | - John. P. Simons
- Chemistry Department, Physical and Theoretical Chemistry Laboratory, Oxford University, South Parks Road, Oxford, OX1 3QZ, U.K
| | - R. Benny Gerber
- Institute of Chemistry and The Fritz Haber Research Center, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel
- Department of Chemistry, University of California, Irvine, California 92697, United States
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5
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Computational studies of the role of glycopyranosyl oxacarbenium ions in glycobiology and glycochemistry. Adv Carbohydr Chem Biochem 2009; 62:83-159. [PMID: 19501705 DOI: 10.1016/s0065-2318(09)00004-3] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Bouteiller Y, Gillet JC, Grégoire G, Schermann JP. Transferable Specific Scaling Factors for Interpretation of Infrared Spectra of Biomolecules from Density Functional Theory. J Phys Chem A 2008; 112:11656-60. [DOI: 10.1021/jp805854q] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Yves Bouteiller
- Laboratoire de Physique des Lasers, UMR CNRS 7538, Institut Galilée, Université Paris 13, 93430, Villetaneuse, France
| | - Jean-Christophe Gillet
- Laboratoire de Physique des Lasers, UMR CNRS 7538, Institut Galilée, Université Paris 13, 93430, Villetaneuse, France
| | - Gilles Grégoire
- Laboratoire de Physique des Lasers, UMR CNRS 7538, Institut Galilée, Université Paris 13, 93430, Villetaneuse, France
| | - Jean Pierre Schermann
- Laboratoire de Physique des Lasers, UMR CNRS 7538, Institut Galilée, Université Paris 13, 93430, Villetaneuse, France
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Kräutler V, Müller M, Hünenberger PH. Conformation, dynamics, solvation and relative stabilities of selected β-hexopyranoses in water: a molecular dynamics study with the gromos 45A4 force field. Carbohydr Res 2007; 342:2097-124. [PMID: 17573054 DOI: 10.1016/j.carres.2007.05.011] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2006] [Revised: 04/06/2007] [Accepted: 05/01/2007] [Indexed: 11/23/2022]
Abstract
The present article reports long timescale (200 ns) simulations of four beta-D-hexopyranoses (beta-D-glucose, beta-D-mannose, beta-D-galactose and beta-D-talose) using explicit-solvent (water) molecular dynamics and vacuum stochastic dynamics simulations together with the GROMOS 45A4 force field. Free-energy and solvation free-energy differences between the four compounds are also calculated using thermodynamic integration. Along with previous experimental findings, the present results suggest that the formation of intramolecular hydrogen-bonds in water is an 'opportunistic' consequence of the close proximity of hydrogen-bonding groups, rather than a major conformational driving force promoting this proximity. In particular, the conformational preferences of the hydroxymethyl group in aqueous environment appear to be dominated by 1,3-syn-diaxial repulsion, with gauche and solvation effects being secondary, and intramolecular hydrogen-bonding essentially negligible. The rotational dynamics of the exocyclic hydroxyl groups, which cannot be probed experimentally, is found to be rapid (10-100 ps timescale) and correlated (flip-flop hydrogen-bonds interconverting preferentially through an asynchronous disrotatory pathway). Structured solvent environments are observed between the ring and lactol oxygen atoms, as well as between the 4-OH and hydroxymethyl groups. The calculated stability differences between the four compounds are dominated by intramolecular effects, while the corresponding differences in solvation free energies are small. An inversion of the stereochemistry at either C(2) or C(4) from equatorial to axial is associated with a raise in free energy. Finally, the particularly low hydrophilicity of beta-D-talose appears to be caused by the formation of a high-occurrence hydrogen-bonded bridge between the 1,3-syn-diaxial 2-OH and 4-OH groups. Overall, good agreement is found with available experimental and theoretical data on the structural, dynamical, solvation and energetic properties of these compounds. However, this detailed comparison also reveals some discrepancies, suggesting the need (and providing a solid basis) for further refinement.
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Affiliation(s)
- Vincent Kräutler
- Laboratory of Physical Chemistry, ETH Zürich, CH-8093 Zürich, Switzerland
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Sturdy YK, Clary DC. Torsional anharmonicity in transition state theory calculations. Phys Chem Chem Phys 2007; 9:2397-405. [PMID: 17492103 DOI: 10.1039/b701014a] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We present a new application for the Torsional Path Integral Monte Carlo (TPIMC) method in which the TPI partition functions are introduced into the calculation of Transition State Theory (TST) rate constants. In this way, an explicit treatment of torsional anharmonicity is included in the TST calculations and the magnitude of these effects can be assessed. The new method is tested on the C(2)H(6) + H hydrogen abstraction reaction and concerted hydrogen transfer in the carbonic acid dimer, for which we have developed torsional potential energy surfaces. For the C(2)H(6) + H reaction the rate constants are halved at room temperature on including a treatment of torsional anharmonicity, while the effects are found to be much smaller for the hydrogen transfer reaction in the carbonic acid dimer.
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Affiliation(s)
- Yvette K Sturdy
- Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford, England.
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Sturdy YK, Clary DC. Torsional anharmonicity in the conformational analysis of tryptamine. Phys Chem Chem Phys 2007; 9:2065-74. [PMID: 17464387 DOI: 10.1039/b615660f] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this paper we calculate the relative conformer populations of the tryptamine molecule. Our approach combines high level electronic structure conformer energies with harmonic frequencies and an anharmonic treatment of the torsional motions using the torsional path integral Monte Carlo method. We have developed a 3-D potential energy surface as a function of the torsional coordinates at the B3LYP/6-31+G(d) level using 2535 grid points. Eight conformers of tryptamine were found to be significantly populated at 430 K as opposed to the experimental observation of seven. This, along with further comparisons with various experimental data, leads us to suppose that conformer interconversion occurs during the cooling phases of many of the experiments. The ordering of the calculated populations fits well with available experimental data. Torsional anharmonicity is found to affect conformer populations more significantly at 430 K than at 100 K (although overall the effects are small), while quantum mechanical effects are not important at either temperature.
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Affiliation(s)
- Yvette K Sturdy
- Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford, UK.
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Ling S, Yu W, Huang Z, Lin Z, Harañczyk M, Gutowski M. Gaseous Arginine Conformers and Their Unique Intramolecular Interactions. J Phys Chem A 2006; 110:12282-91. [PMID: 17078626 DOI: 10.1021/jp0645115] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Extensive ab initio calculations were employed to characterize stable conformers of gaseous arginine, both the canonical and zwitterionic tautomers. Step-by-step geometry optimizations of possible single-bond rotamers at the B3LYP/6-31G(d), B3LYP/6-31++G(d,p), and MP2/6-31++G(d,p) levels yield numerous structures that are more stable than any known ones. The final electronic energies of the conformers were determined at the CCSD/6-31++G(d,p) level. The lowest energies of the canonical and zwitterionic structures are lower than the existing values by 2.0 and 2.3 kcal/mol, respectively. The relative energies, rotational constants, dipole moments, and harmonic frequencies of the stable conformers remain for future experimental verification. The conformational distributions at various temperatures, estimated according to thermodynamic principles, consist almost exclusively of the newly found structures. One striking feature is the occurrence of blue-shifting hydrogen bonds in all six of the most stable conformers. A unique feature of important conformations is the coexistence of dihydrogen and blue- and red-shifting hydrogen bonds. In addition to the hydrogen bonds, the stereoelectronic effects were also found to be important stabilization factors. The calculated and measured proton affinities agree within the theoretical and experimental uncertainties, affirming the high quality of our conformational search. The theoretical gas-phase basicity of 245.9 kcal/mol is also in good agreement with the experimental value of 240.6 kcal/mol. The extensive searches establish firmly that gaseous arginine exists primarily in the canonical and not the zwitterionic form.
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Affiliation(s)
- Sanliang Ling
- Hefei National Laboratory for Physical Sciences at Microscale, Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
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