1
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Thorpe JH, Windom ZW, Bartlett RJ, Matthews DA. Factorized Quadruples and a Predictor of Higher-Level Correlation in Thermochemistry. J Phys Chem A 2024. [PMID: 39194317 DOI: 10.1021/acs.jpca.4c04460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/29/2024]
Abstract
Coupled cluster theory has had a momentous impact on the ab initio prediction of molecular properties, and remains a staple ingratiate in high-accuracy thermochemical model chemistries. However, these methods require inclusion of at least some connected quadruple excitations, which generally scale at best as O ( N 9 ) with the number of basis functions. It is very difficult to predict, a priori, the effect correlation of past CCSD(T) on a given reaction energy. The purpose of this work is to examine cost-effective quadruple corrections based on the factorization theorem of the many-body perturbation theory that may address these challenges. We show that the O ( N 7 ) factorized CCSD(TQf) method introduces minimal error to predicted correlation and reaction energies as compared to the O ( N 9 ) CCSD(TQ). Further, we examine the performance of Goodson's continued fraction method in the estimation of CCSDT(Q)Λ contributions to reaction energies as well as a "new" method related to %TAE[(T)] that we refer to as a scaled perturbation estimator. We find that the scaled perturbation estimator based upon CCSD(TQf)/cc-pVDZ is capable of predicting CCSDT(Q)Λ/cc-pVDZ contributions to reaction energies with an average error of 0.07 kcal mol-1 and an L2D of 0.52 kcal mol-1 when applied to a test-suite of nearly 3000 reactions. This offers a means by which to reliably "ballpark" how important post-CCSD(T) contributions are to reaction energies while incurring no more than CCSD(T) formal cost and a little mental math.
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Affiliation(s)
- James H Thorpe
- Department of Chemistry, Southern Methodist University, Dallas, Texas 75275, United States
| | - Zachary W Windom
- Quantum Theory Project, University of Florida, Gainesville, Florida 32611, United States
| | - Rodney J Bartlett
- Quantum Theory Project, University of Florida, Gainesville, Florida 32611, United States
| | - Devin A Matthews
- Department of Chemistry, Southern Methodist University, Dallas, Texas 75275, United States
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2
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Thorpe JH, Feller D, Bross DH, Ruscic B, Stanton JF. Sub 20 cm -1 computational prediction of the CH bond energy - a case of systematic error in computational thermochemistry. Phys Chem Chem Phys 2023; 25:21162-21172. [PMID: 36200428 DOI: 10.1039/d2cp03964h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The bond dissociation energy of methylidyne, D0(CH), is studied using an improved version of the High-Accuracy Extrapolated ab initio Thermochemistry (HEAT) approach as well as the Feller-Peterson-Dixon (FPD) model chemistry. These calculations, which include basis sets up to nonuple (aug-cc-pCV9Z) quality, are expected to be capable of providing results substantially more accurate than the ca. 1 kJ mol-1 level that is characteristic of standard high-accuracy protocols for computational thermochemistry. The calculated 0 K CH bond energy (27 954 ± 15 cm-1 for HEAT and 27 956 ± 15 cm-1 for FPD), along with equivalent treatments of the CH ionization energy and the CH+ dissociation energy (85 829 ± 15 cm-1 and 32 946 ± 15 cm-1, respectively), were compared to the existing benchmarks from Active Thermochemical Tables (ATcT), uncovering an unexpected difference for D0(CH). This has prompted a detailed reexamination of the provenance of the corresponding ATcT benchmark, allowing the discovery and subsequent correction of a systematic error present in several published high-level calculations, ultimately yielding an amended ATcT benchmark for D0(CH). Finally, the current theoretical results were added to the ATcT Thermochemical Network, producing refined ATcT estimates of 27 957.3 ± 6.0 cm-1 for D0(CH), 32 946.7 ± 0.6 cm-1 for D0(CH+), and 85 831.0 ± 6.0 cm-1 for IE(CH).
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Affiliation(s)
- James H Thorpe
- The Quantum Theory Project, Department of Chemistry, University of Florida, Gainesville, Florida, 32611, USA.
| | - David Feller
- Washington State University, Pullman, Washington 99164-4630, USA
- University of Alabama, Tuscaloosa, Alabama 35487-0336, USA
| | - David H Bross
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.
| | - Branko Ruscic
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.
| | - John F Stanton
- The Quantum Theory Project, Department of Chemistry, University of Florida, Gainesville, Florida, 32611, USA.
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3
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Kreitz B, Abeywardane K, Goldsmith CF. Linking Experimental and Ab Initio Thermochemistry of Adsorbates with a Generalized Thermochemical Hierarchy. J Chem Theory Comput 2023. [PMID: 37354113 DOI: 10.1021/acs.jctc.3c00112] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/26/2023]
Abstract
Enthalpies of formation of adsorbates are crucial parameters in the microkinetic modeling of heterogeneously catalyzed reactions since they quantify the stability of intermediates on the catalyst surface. This quantity is often computed using density functional theory (DFT), as more accurate methods are computationally still too expensive, which means that the derived enthalpies have a large uncertainty. In this study, we propose a new error cancellation method to compute the enthalpies of formation of adsorbates from DFT more accurately through a generalized connectivity-based hierarchy. The enthalpy of formation is determined through a hypothetical reaction that preserves atomistic and bonding environments. The method is applied to a data set of 60 adsorbates on Pt(111) with up to 4 heavy (non-hydrogen) atoms. Enthalpies of formation of the fragments required for the bond balancing reactions are based on experimental heats of adsorption for Pt(111). The comparison of enthalpies of formation derived from different DFT functionals using the isodesmic reactions shows that the effect of the functional is significantly reduced due to the error cancellation. Thus, the proposed methodology creates an interconnected thermochemical network of adsorbates that combines experimental with ab initio thermochemistry in a single and more accurate thermophysical database.
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Affiliation(s)
- Bjarne Kreitz
- School of Engineering, Brown University, Providence, Rhode Island 02912, United States
| | - Kento Abeywardane
- School of Engineering, Brown University, Providence, Rhode Island 02912, United States
| | - C Franklin Goldsmith
- School of Engineering, Brown University, Providence, Rhode Island 02912, United States
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4
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Elliott SN, Keçeli M, Ghosh MK, Somers KP, Curran HJ, Klippenstein SJ. High-Accuracy Heats of Formation for Alkane Oxidation: From Small to Large via the Automated CBH-ANL Method. J Phys Chem A 2023; 127:1512-1531. [PMID: 36695527 DOI: 10.1021/acs.jpca.2c07248] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
It is generally challenging to obtain high-accuracy predictions for the heat of formation for species with more than a handful of heavy atoms, such as those of importance in standard combustion mechanisms. To this end, we construct the CBH-ANL approach and illustrate that, for a set of 194 alkane oxidation species, it can be used to produce ΔHf(0 K) values with 2σ uncertainties of 0.2-0.5 kcal mol-1. This set includes the alkanes, hydroperoxides, and alkyl, peroxy, and hydroperoxyalkyl radicals for 17 representative hydrocarbon fuels containing up to 10 heavy atoms with various degrees of branching in the alkane backbone. The CBH-ANL approach, automated in the QTC and AutoMech software suites, builds balanced chemical equations for the calculation of ΔHf(0 K), in which the reference species may be up to five heavy atoms. The high-level ANL0 and ANL1 reference ΔHf(0 K) values are further refined for even the largest of these reference species with a novel laddering approach. We perform a comprehensive quantification of the uncertainties for both the individual reference species (the largest of which is 0.15 kcal mol-1) and the propagation of those uncertainties when used in the calculation of ΔHf(0 K) for the 194 target species. We examine the sensitivity of the predicted ΔHf(0 K) values to (i) electronic energies from various methods, including ωB97X-D/cc-pVTZ, B2PLYP-D3/cc-pVTZ, CCSD(T)-F12b/cc-pVDZ-F12//B2PLYP-D3/cc-pVTZ, and CCSD(T)-F12b/cc-pVTZ-F12//B2PLYP-D3/cc-pVTZ; (ii) the zero-point vibrational energies (ZPVEs), where we consider harmonic ZPVEs as well as two scaling-based estimates of the anharmonic ZPVEs, all implemented for both ωB97X-D/cc-pVTZ and B2PLYP-D3/cc-pVTZ calculations; (iii) the particular CBH-ANL scheme employed; and (iv) the procedure for choosing the reference conformer for the analyses. The discussion concludes with a summary of the estimated overall uncertainty in the predictions and a validation of the predictions for the alkane subset.
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Affiliation(s)
- Sarah N Elliott
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois60439, United States
| | - Murat Keçeli
- Computational Science Division, Argonne National Laboratory, Lemont, Illinois60439, United States
| | - Manik K Ghosh
- Combustion Chemistry Centre, School of Chemistry, Ryan Institute, MaREI, National University of Ireland, GalwayH91 TK33, Ireland
| | - Kieran P Somers
- Combustion Chemistry Centre, School of Chemistry, Ryan Institute, MaREI, National University of Ireland, GalwayH91 TK33, Ireland
| | - Henry J Curran
- Combustion Chemistry Centre, School of Chemistry, Ryan Institute, MaREI, National University of Ireland, GalwayH91 TK33, Ireland
| | - Stephen J Klippenstein
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois60439, United States
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5
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Barone V, Fusè M, Lazzari F, Mancini G. Benchmark Structures and Conformational Landscapes of Amino Acids in the Gas Phase: A Joint Venture of Machine Learning, Quantum Chemistry, and Rotational Spectroscopy. J Chem Theory Comput 2023; 19:1243-1260. [PMID: 36731119 PMCID: PMC9979611 DOI: 10.1021/acs.jctc.2c01143] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The accurate characterization of prototypical bricks of life can strongly benefit from the integration of high resolution spectroscopy and quantum mechanical computations. We have selected a number of representative amino acids (glycine, alanine, serine, cysteine, threonine, aspartic acid and asparagine) to validate a new computational setup rooted in quantum-chemical computations of increasing accuracy guided by machine learning tools. Together with low-lying energy minima, the barriers ruling their interconversion are evaluated in order to unravel possible fast relaxation paths. Vibrational and thermal effects are also included in order to estimate relative free energies at the temperature of interest in the experiment. The spectroscopic parameters of all the most stable conformers predicted by this computational strategy, which do not have low-energy relaxation paths available, closely match those of the species detected in microwave experiments. Together with their intrinsic interest, these accurate results represent ideal benchmarks for more approximate methods.
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Affiliation(s)
- Vincenzo Barone
- Scuola
Normale Superiore di Pisa, piazza dei Cavalieri 7, 56126 Pisa, Italy,
| | - Marco Fusè
- DMMT-sede
Europa, Universitá di Brescia, viale Europa 11, 25121 Brescia, Italy
| | - Federico Lazzari
- Scuola
Normale Superiore di Pisa, piazza dei Cavalieri 7, 56126 Pisa, Italy
| | - Giordano Mancini
- Scuola
Normale Superiore di Pisa, piazza dei Cavalieri 7, 56126 Pisa, Italy
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6
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LaGrotta CE, Meng Q, Lei L, Barbet MC, Hong Z, Burke MP. Resolving Discrepancies between State-of-the-Art Theory and Experiment for HO 2 + HO 2 via Multiscale Informatics. J Phys Chem A 2023; 127:799-816. [PMID: 36648878 DOI: 10.1021/acs.jpca.2c07297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Recent high-level theoretical calculations predict a mild temperature dependence for HO2 + HO2 inconsistent with state-of-the-art experimental determinations that upheld the stronger temperature dependence observed in early experiments. Via MultiScale Informatics analysis of the theoretical and experimental data, we identified an alternative interpretation of the raw experimental data that uses HO2 + HO2 rate constants nearly identical to theoretical predictions─implying that the theoretical and experimental data are actually consistent, at least when considering the raw data from experimental studies. Similar analyses of typical signals from low-temperature experiments indicate that an HOOOOH intermediate─identified by recent theory but absent from earlier interpretations─yields modest effects that are smaller than, but may have contributed to, the scatter in data among different experiments. More generally, the findings demonstrate that modern chemical theories and experiments have progressed to a point where meaningful comparison requires joint consideration of their data simultaneously.
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Affiliation(s)
- Carly E LaGrotta
- Department of Mechanical Engineering, Columbia University, New York, New York10027, United States
| | - Qinghui Meng
- Department of Mechanical Engineering, Columbia University, New York, New York10027, United States
| | - Lei Lei
- Department of Mechanical Engineering, Columbia University, New York, New York10027, United States
| | - Mark C Barbet
- Department of Mechanical Engineering, Columbia University, New York, New York10027, United States
| | - Zekai Hong
- Aerospace Research Center, National Research Council of Canada, Ottawa, OntarioK1A 0R6, Canada
| | - Michael P Burke
- Department of Mechanical Engineering, Columbia University, New York, New York10027, United States.,Department of Chemical Engineering, Columbia University, New York, New York10027, United States.,Data Science Institute, Columbia University, New York, New York10027, United States
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7
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Kędziera D, Rauhut G, Császár AG. Structure, energetics, and spectroscopy of the chromophores of HHe+n, H 2He+n, and He+n clusters and their deuterated isotopologues. Phys Chem Chem Phys 2022; 24:12176-12195. [PMID: 35543594 DOI: 10.1039/d1cp05535f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The linear molecular ions H2He+, HHe+2, and He+3 are the central units (chromophores) of certain He-solvated complexes of the H2He+n, HHe+n, and He+n families, respectively. These are complexes which do exist, according to mass-spectrometry studies, up to very high n values. Apparently, for some of the H2He+n and He+n complexes, the linear symmetric tetratomic H2He+2 and the diatomic He+2 cations, respectively, may also be the central units. In this study, definitive structures, relative energies, zero-point vibrational energies, and (an)harmonic vibrational fundamentals, and, in some cases, overtones and combination bands, are established mostly for the triatomic chromophores. The study is also extended to the deuterated isotopologues D2He+, DHe+2, and D2He+2. To facilitate and improve the electronic-structure computations performed, new atom-centered, fixed-exponent, Gaussian-type basis sets called MAX, with X = T(3), Q(4), P(5), and H(6), are designed for the H and He atoms. The focal-point-analysis (FPA) technique is employed to determine definitive relative energies with tight uncertainties for reactions involving the molecular ions. The FPA results determined include the 0 K proton and deuteron affinities of the 4He atom, 14 875(9) cm-1 [177.95(11) kJ mol-1] and 15 229(8) cm-1 [182.18(10) kJ mol-1], respectively, the dissociation energies of the He+2 → He+ + He, HHe+2 → HHe+ + He, and He+3 → He+2 + He reactions, 19 099(13) cm-1 [228.48(16) kJ mol-1], 3948(7) cm-1 [47.23(8) kJ mol-1], and 1401(12) cm-1 [16.76(14) kJ mol-1], respectively, the dissociation energy of the DHe+2 → DHe+ + He reaction, 4033(6) cm-1 [48.25(7) kJ mol-1], the isomerization energy between the two linear isomers of the [H, He, He]+ system, 3828(40) cm-1 [45.79(48) kJ mol-1], and the dissociation energies of the H2He+ → H+2 + He and the H2He+2 → H2He+ + He reactions, 1789(4) cm-1 [21.40(5) kJ mol-1] and 435(6) cm-1 [5.20(7) kJ mol-1], respectively. The FPA estimates of the first dissociation energy of D2He+ and D2He+2 are 1986(4) cm-1 [23.76(5) kJ mol-1] and 474(5) cm-1 [5.67(6) kJ mol-1], respectively. Determining the vibrational fundamentals of the triatomic chromophores with second-order vibrational perturbation theory (VPT2) and vibrational configuration interaction (VCI) techniques, both built around the Eckart-Watson Hamiltonian, proved unusually challenging. For the species studied, VPT2 has difficulties yielding dependable results, in some cases even for the fundamentals of the H-containing molecular cations, while carefully executed VCI computations yield considerably improved spectroscopic results. In a few cases unusually large anharmonic corrections to the fundamentals, on the order of 15% of the harmonic value, have been observed.
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Affiliation(s)
- Dariusz Kędziera
- Faculty of Chemistry, Nicolaus Copernicus University in Torun, 87-100 Torun, Poland.
| | - Guntram Rauhut
- Institute for Theoretical Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany.
| | - Attila G Császár
- Laboratory of Molecular Structure and Dynamics, Institute of Chemistry, ELTE Eötvös Loránd University and MTA-ELTE Complex Chemical Systems Research Group, Pázmány Péter sétány 1/A, H-1117 Budapest, Hungary.
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8
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Alibakhshi A, Schäfer LV. Accurate evaluation of combustion enthalpy by ab-intio computations. Sci Rep 2022; 12:5834. [PMID: 35388104 PMCID: PMC8987062 DOI: 10.1038/s41598-022-09844-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 03/22/2022] [Indexed: 11/24/2022] Open
Abstract
Accurate evaluation of combustion enthalpy is of high scientific and industrial importance. Although ab-initio computation of the heat of reactions is one of the promising and well-established approaches in computational chemistry, reliable and precise computation of heat of combustion reactions by ab-initio methods is surprisingly scarce in the literature. A handful of works carried out for this purpose report significant inconsistencies between the computed and experimentally determined combustion enthalpies and suggest empirical corrections to improve the accuracy of the ab-initio predicted data. The main aim of the present study is to investigate the reasons behind those reported inconsistencies and propose guidelines for a high-accuracy estimation of heat of reactions via ab-initio computations. We show comparably accurate prediction of combustion enthalpy of 40 organic molecules based on a DSD-PBEP86 double-hybrid density functional theory approach and CCSD(T)-F12 coupled-cluster computations, with mean unsigned errors with respect to experimental data being below 0.5% for both methods.
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Affiliation(s)
- Amin Alibakhshi
- Theoretical Chemistry, Institute for Physical Chemistry, Christian-Albrechts-University, Olshausenstr. 40, 24118, Kiel, Germany. .,Theoretical Chemistry, Ruhr University Bochum, 44780, Bochum, Germany.
| | - Lars V Schäfer
- Theoretical Chemistry, Ruhr University Bochum, 44780, Bochum, Germany
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9
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Andersen JH, Nanda KD, Krylov AI, Coriani S. Probing Molecular Chirality of Ground and Electronically Excited States in the UV-vis and X-ray Regimes: An EOM-CCSD Study. J Chem Theory Comput 2022; 18:1748-1764. [PMID: 35187935 DOI: 10.1021/acs.jctc.1c00937] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We present several strategies for computing electronic circular dichroism (CD) spectra across different frequency ranges at the equation-of-motion coupled-cluster singles and doubles level of theory. CD spectra of both ground and electronically excited states are discussed. For selected cases, the approach is compared with coupled-cluster linear response results as well as time-dependent density functional theory. The extension of the theory to include the effect of spin-orbit coupling is presented and illustrated by calculations of X-ray CD spectra at the L-edge.
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Affiliation(s)
- Josefine H Andersen
- DTU Chemistry, Technical University of Denmark, Kemitorvet Bldg 207, DK-2800 Kongens Lyngby, Denmark
| | - Kaushik D Nanda
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Anna I Krylov
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Sonia Coriani
- DTU Chemistry, Technical University of Denmark, Kemitorvet Bldg 207, DK-2800 Kongens Lyngby, Denmark
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10
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Klippenstein SJ. Spiers Memorial Lecture: theory of unimolecular reactions. Faraday Discuss 2022; 238:11-67. [DOI: 10.1039/d2fd00125j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
One hundred years ago, at an earlier Faraday Discussion meeting, Lindemann presented a mechanism that provides the foundation for contemplating the pressure dependence of unimolecular reactions. Since that time, our...
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11
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David J, Gómez S, Guerra D, Guerra D, Restrepo A. A Comprehensive Picture of the Structures, Energies, and Bonding in the Alanine Dimers. Chemphyschem 2021; 22:2401-2412. [PMID: 34554628 DOI: 10.1002/cphc.202100585] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 09/22/2021] [Indexed: 12/14/2022]
Abstract
High level quantum mechanical computations and extensive stochastic searches of the potential energy surfaces of the Alanine dimers uncover rich and complex structural and interaction landscapes. A total of 416 strongly bound (up 13.4 kcal mol-1 binding energies at the DLPNO-CCSD(T)/6-311++G(d,p) level corrected by the basis set superposition error and by the zero point vibrational energies over B3LYP-D3 geometries), close energy equilibrium structures were located, bonded via 32 specific types of intermolecular contacts including Y⋅⋅⋅H-X primary and Y⋅⋅⋅H-C secondary hydrogen bonds, H⋅⋅⋅H dihydrogen contacts, and non conventional anti-electrostatic Y δ - ⋯ X δ - interactions. The putative global minimum is triply degenerate, corresponding to the structure of the common dimer of a carboxylic acid. All quantum descriptors of chemical bonding point to a multitude of weak individual interactions within each dimer, whose cumulative effect results in large binding energies and in an attractive fluxional wall of non-covalent interactions in the interstitial region between the monomers.
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Affiliation(s)
- Jorge David
- Escuela de Ciencias, Departamento de Ciencias Físicas, Universidad Eafit, AA 3300, Medellín, Colombia
| | - Sara Gómez
- Scuola Normale Superiore, Classe di Scienze, Piazza dei Cavalieri 7, 56126, Pisa, Italy
| | - Doris Guerra
- Instituto de Química, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín, Colombia
| | - Dario Guerra
- Departamento de Educación y Ciencias Básicas, Instituto Tecnológico Metropolitano, Calle 73 No. 76 A-354, Medellín, Colombia
| | - Albeiro Restrepo
- Instituto de Química, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín, Colombia
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12
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Sheng M, Silvestrini F, Biczysko M, Puzzarini C. Structural and Vibrational Properties of Amino Acids from Composite Schemes and Double-Hybrid DFT: Hydrogen Bonding in Serine as a Test Case. J Phys Chem A 2021; 125:9099-9114. [PMID: 34623165 DOI: 10.1021/acs.jpca.1c06993] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The structures, relative stabilities, and vibrational wavenumbers of the two most stable conformers of serine, stabilized by the O-H···N, O-H···O═C and N-H···O-H intramolecular hydrogen bonds, have been evaluated by means of state-of-the-art composite schemes based on coupled-cluster (CC) theory. The so-called "cheap" composite approach (CCSD(T)/(CBS+CV)MP2) allowed determination of accurate equilibrium structures and harmonic vibrational wavenumbers, also pointing out significant corrections beyond the CCSD(T)/cc-pVTZ level. These accurate results stand as a reference for benchmarking selected hybrid and double-hybrid, dispersion-corrected DFT functionals. B2PLYP-D3 and DSDPBEP86 in conjunction with a triple-ζ basis set have been confirmed as effective methodologies for structural and spectroscopic studies of medium-sized flexible biomolecules, also showing intramolecular hydrogen bonding. These best performing double-hybrid functionals have been employed to simulate IR spectra by means of vibrational perturbation theory, also considering hybrid CC/DFT schemes. The best overall agreement with experiment, with mean absolute error of 8 cm-1, has been obtained by combining CCSD(T)/(CBS+CV)MP2 harmonic wavenumbers with B2PLYP-D3/maug-cc-pVTZ anharmonic corrections. Finally, a composite scheme entirely based on CCSD(T) calculations (CCSD(T)/CBS+CV) has been employed for energetics, further confirming that serine II is the most stable conformer, also when zero-point vibrational energy corrections are included.
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Affiliation(s)
- Mingzhu Sheng
- International Centre for Quantum and Molecular Structures, Physics Department, Shanghai University, 99 Shangda Road, Shanghai, 200444, China
| | - Filippo Silvestrini
- Department of Chemistry "Giacomo Ciamician", University of Bologna, Via F. Selmi 2, 40126 Bologna, Italy
| | - Malgorzata Biczysko
- International Centre for Quantum and Molecular Structures, Physics Department, Shanghai University, 99 Shangda Road, Shanghai, 200444, China
| | - Cristina Puzzarini
- Department of Chemistry "Giacomo Ciamician", University of Bologna, Via F. Selmi 2, 40126 Bologna, Italy
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13
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Sookhaki E, Namazian M. A molecular modeling of iodinated organic compounds. J Mol Graph Model 2021; 108:107985. [PMID: 34315067 DOI: 10.1016/j.jmgm.2021.107985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 06/25/2021] [Accepted: 07/06/2021] [Indexed: 10/20/2022]
Abstract
Thermodynamic quantities of some iodinated compounds have been studied by means of ab initio and density functional theory calculations. Since there are some limitations for heavy elements in the fifth row of periodic table such as the iodine atom, a high level of ab initio theory is developed to calculate the energy of iodinated compounds. The standard enthalpies of formation for alkyl iodides and other iodinated organic compounds have been computed and compared with available experimental data. The impact of iodine atoms on the change of enthalpies for deprotonation of iodobenzenes has been studied and a mathematical model is proposed for the effect of iodine on the change of deprotonation. The acidity of diiodophenols as a model for thyroxin hormone has been successfully calculated. The barriers for nucleophilic reactions of substituted methyl iodides are investigated and the energy profiles are characterized by double-well potentials which correspond to pre-reaction and post-reaction complexes, separated by a transition state.
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Affiliation(s)
- Elham Sookhaki
- Department of Chemistry, Faculty of Science, Yazd University, Yazd, P.O. Box, 89195-741, Iran
| | - Mansoor Namazian
- Department of Chemistry, Faculty of Science, Yazd University, Yazd, P.O. Box, 89195-741, Iran.
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14
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Affiliation(s)
- James H. Thorpe
- The Quantum Theory Project, Department of Chemistry, The University of Florida, Gainesville, FL, USA
| | - John F. Stanton
- The Quantum Theory Project, Department of Chemistry, The University of Florida, Gainesville, FL, USA
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15
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Thorpe JH, Lopez CA, Nguyen TL, Baraban JH, Bross DH, Ruscic B, Stanton JF. High-accuracy extrapolated ab initio thermochemistry. IV. A modified recipe for computational efficiency. J Chem Phys 2019; 150:224102. [DOI: 10.1063/1.5095937] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Affiliation(s)
- James H. Thorpe
- The Quantum Theory Project, Department of Chemistry, The University of Florida, Gainesville, Florida 32611, USA
| | - Chris A. Lopez
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Thanh Lam Nguyen
- The Quantum Theory Project, Department of Chemistry, The University of Florida, Gainesville, Florida 32611, USA
| | - Joshua H. Baraban
- Department of Chemistry, Ben-Gurion University of the Negev, Be’er-Sheva 8410501, Israel
| | - David H. Bross
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Branko Ruscic
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - John F. Stanton
- The Quantum Theory Project, Department of Chemistry, The University of Florida, Gainesville, Florida 32611, USA
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16
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Loupas A, Gorfinkiel JD. Shape and core-excited resonances in electron scattering from alanine. J Chem Phys 2019; 150:064307. [PMID: 30769999 DOI: 10.1063/1.5081813] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
We present detailed ab initio scattering calculations using the R-matrix method for electron collisions with the most stable conformer of α-alanine. The shape resonances that we identify are in good agreement with earlier calculations and experiments. Core-excited and mixed-character resonances are identified and characterized computationally for the first time. Dissociative electron attachment results are discussed in relation to the resonances identified.
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Affiliation(s)
- Alexandra Loupas
- Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus de Caparica, Lisboa 2829-516, Portugal
| | - Jimena D Gorfinkiel
- School of Physical Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA, United Kingdom
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18
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19
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Lobo IA, Robertson PA, Villani L, Wilson DJD, Robertson EG. Thiols as Hydrogen Bond Acceptors and Donors: Spectroscopy of 2-Phenylethanethiol Complexes. J Phys Chem A 2018; 122:7171-7180. [PMID: 30113835 DOI: 10.1021/acs.jpca.8b06649] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Evidence and understanding of sulfur-centered hydrogen bonding, especially where the donor is a thiol, lags far behind that for conventional OH interactions. To help address this deficiency, conformer specific IR spectra of 2-phenylethanethiol (PET) and associated 1:1 solvent complexes have been measured in SH, OH, and CH stretch regions using resonant-two-photon-ionization (R2PI) and IR-UV ion dip spectroscopic techniques. The aromatic and aliphatic CH stretch regions show signature differences between anti and gauche conformers. Supported by ab initio calculations, a PET-water cluster with an OH···S arrangement and a PET-diethyl ether cluster expressing an SH···O interaction were identified. The SH stretch band of the SH···O complex is red-shifted and undergoes significant intensity enhancement compared to the bare molecule, which is characteristic of hydrogen bonding. These findings offer insight into the nature of the thiol functional group as a potential hydrogen bond donor and acceptor.
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Affiliation(s)
- Isabella A Lobo
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science , La Trobe University , Melbourne , 3086 , Victoria Australia
| | - Patrick A Robertson
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science , La Trobe University , Melbourne , 3086 , Victoria Australia
| | - Luigi Villani
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science , La Trobe University , Melbourne , 3086 , Victoria Australia
| | - David J D Wilson
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science , La Trobe University , Melbourne , 3086 , Victoria Australia
| | - Evan G Robertson
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science , La Trobe University , Melbourne , 3086 , Victoria Australia
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20
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Malar EJP, Divya P. Structural Stability in Dimer and Tetramer Clusters of l-Alanine in the Gas Phase and the Feasibility of Peptide Bond Formation. J Phys Chem B 2018; 122:6462-6470. [DOI: 10.1021/acs.jpcb.8b01629] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- E. J. Padma Malar
- National Centre for Ultrafast Processes, University of Madras, Taramani Campus, Chennai 600113, India
| | - P. Divya
- National Centre for Ultrafast Processes, University of Madras, Taramani Campus, Chennai 600113, India
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21
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Tóbiás R, Császár AG, Gyevi-Nagy L, Tasi G. Definitive thermochemistry and kinetics of the interconversions among conformers of n-butane and n-pentane. J Comput Chem 2018; 39:424-437. [PMID: 29239472 DOI: 10.1002/jcc.25130] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 10/27/2017] [Accepted: 10/31/2017] [Indexed: 11/09/2022]
Abstract
The focal-point analysis (FPA) technique is used for the definitive characterization of conformational interconversion parameters, including activation energy barriers, activation free energies, and kinetic rate coefficients at 298 K, of two n-alkanes, n-butane, and n-pentane, yielding the first complete analysis of their interconversion kinetics. The FPA implementation developed in this study is based on geometry optimizations and harmonic frequency computations carried out with density functional theory methods and single-point energy computations up to the CCSD(T) level of electronic structure theory using atom-centered Gaussian basis sets as large as cc-pV5Z. The anharmonic vibrational computations are carried out, at the MP2/6-31G* level of theory. Reflecting the convergence behavior of the Gibbs free-energy terms and the interconversion parameters, well-defined uncertainties, mostly neglected in previous theoretical studies, are provided. Finally, the effect of these uncertainties on the concentrations of the conformers of n-butane and n-pentane is examined via a global Monte-Carlo uncertainty analysis. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Roland Tóbiás
- MTA-ELTE Complex Chemical Systems Research Group, H-1518 Budapest 112, P.O. Box 32, Hungary
| | - Attila G Császár
- MTA-ELTE Complex Chemical Systems Research Group, H-1518 Budapest 112, P.O. Box 32, Hungary.,Laboratory of Molecular Structure and Dynamics, Institute of Chemistry, Eötvös Loránd University, H-1117 Budapest, Pázmány Péter sétány 1/A, Hungary
| | - László Gyevi-Nagy
- Department of Physical Chemistry and Materials Science, University of Szeged, H-6720 Szeged, Rerrich B. tér 1, Hungary
| | - Gyula Tasi
- Department of Applied and Environmental Chemistry, University of Szeged, H-6720 Szeged, Rerrich B. tér 1, Hungary
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22
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Vogt N, Demaison J, Rudolph HD, Juanes M, Fernández J, Lesarri A. Semiexperimental and mass-dependent structures by the mixed regression method: Accurate equilibrium structure and failure of the Kraitchman method for ethynylcyclohexane. J Chem Phys 2018; 148:064306. [DOI: 10.1063/1.5018053] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Natalja Vogt
- Section of Chemical Information Systems, University of Ulm, Albert-Einstein-Allee 47, 89081 Ulm, Germany
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Jean Demaison
- Section of Chemical Information Systems, University of Ulm, Albert-Einstein-Allee 47, 89081 Ulm, Germany
| | - Heinz Dieter Rudolph
- Section of Chemical Information Systems, University of Ulm, Albert-Einstein-Allee 47, 89081 Ulm, Germany
| | - Marcos Juanes
- Departamento de Química Física y Química Inorgánica, Facultad de Ciencias, Universidad de Valladolid, Paseo de Belén, 7, 47011 Valladolid, Spain
| | - Jairo Fernández
- Departamento de Química Física y Química Inorgánica, Facultad de Ciencias, Universidad de Valladolid, Paseo de Belén, 7, 47011 Valladolid, Spain
| | - Alberto Lesarri
- Departamento de Química Física y Química Inorgánica, Facultad de Ciencias, Universidad de Valladolid, Paseo de Belén, 7, 47011 Valladolid, Spain
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23
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Indubala E, Dhanasekar M, Sudha V, Malar EJP, Divya P, Sherine J, Rajagopal R, Bhat SV, Harinipriya S. l-Alanine capping of ZnO nanorods: increased carrier concentration in ZnO/CuI heterojunction diode. RSC Adv 2018; 8:5350-5361. [PMID: 35542426 PMCID: PMC9078177 DOI: 10.1039/c7ra12385j] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 01/16/2018] [Indexed: 12/19/2022] Open
Abstract
ZnO nanorods were capped with a simple amino acid, viz., l-alanine to increase the carrier concentration and improve the performance of ZnO/CuI heterojunction diodes. The effect of l-alanine capping on the morphology, structural, optical, electrochemical and electrical properties of ZnO nanorods had been studied in detail. The stable structure with two equally strong Zn–O coordinate bonds predicted by density functional theory was in agreement with the experimental results of FTIR spectroscopy. Due to the presence of electron-releasing (+I effect) moieties in l-Alanine, the carrier concentration of capped ZnO nanorods was two orders of magnitude higher and the ZnO/CuI heterojunction device showed more than a two-fold increase in the photovoltaic power conversion efficiency. ZnO nanorods were capped with a simple amino acid, viz., l-Alanine to increase the carrier concentration and improve the performance of ZnO/CuI heterojunction diodes.![]()
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Affiliation(s)
- E. Indubala
- Electrochemical Systems Lab
- SRM Research Institute
- SRM Institute of Science and Technology
- Chennai – 603203
- India
| | - M. Dhanasekar
- SRM Research Institute
- SRM Institute of Science and Technology
- Chennai – 603203
- India
- Department of Physics and Nanotechnology
| | - V. Sudha
- Department of Chemistry
- SRM Institute of Science and Technology
- Chennai – 603203
- India
| | - E. J. Padma Malar
- National Centre for Ultrafast Processes
- University of Madras
- Chennai – 600 113
- India
| | - P. Divya
- National Centre for Ultrafast Processes
- University of Madras
- Chennai – 600 113
- India
| | - Jositta Sherine
- Department of Physics and Nanotechnology
- SRM Institute of Science and Technology
- Chennai – 603203
- India
| | | | - S. Venkataprasad Bhat
- SRM Research Institute
- SRM Institute of Science and Technology
- Chennai – 603203
- India
- Department of Physics and Nanotechnology
| | - S. Harinipriya
- Electrochemical Systems Lab
- SRM Research Institute
- SRM Institute of Science and Technology
- Chennai – 603203
- India
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24
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Mata RA, Suhm MA. Benchmarking Quantum Chemical Methods: Are We Heading in the Right Direction? Angew Chem Int Ed Engl 2017; 56:11011-11018. [PMID: 28452424 PMCID: PMC5582598 DOI: 10.1002/anie.201611308] [Citation(s) in RCA: 100] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 12/20/2016] [Indexed: 11/15/2022]
Abstract
Theoreticians and experimentalists should work together more closely to establish reliable rankings and benchmarks for quantum chemical methods. Comparison to carefully designed experimental benchmark data should be a priority. Guidelines to improve the situation for experiments and calculations are proposed.
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Affiliation(s)
- Ricardo A. Mata
- Institut für Physikalische ChemieUniversität GöttingenTammannstrasse 637077GöttingenGermany
| | - Martin A. Suhm
- Institut für Physikalische ChemieUniversität GöttingenTammannstrasse 637077GöttingenGermany
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25
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Klippenstein SJ, Harding LB, Ruscic B. Ab Initio Computations and Active Thermochemical Tables Hand in Hand: Heats of Formation of Core Combustion Species. J Phys Chem A 2017; 121:6580-6602. [DOI: 10.1021/acs.jpca.7b05945] [Citation(s) in RCA: 106] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Stephen J. Klippenstein
- Chemical Sciences and Engineering
Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Lawrence B. Harding
- Chemical Sciences and Engineering
Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Branko Ruscic
- Chemical Sciences and Engineering
Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
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26
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Chan B, Moran D, Easton CJ, Radom L. Impact of Hydrogen Bonding on the Susceptibility of Peptides to Oxidation. Chem Asian J 2017; 12:1485-1489. [PMID: 28544486 DOI: 10.1002/asia.201700492] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Indexed: 01/12/2023]
Abstract
The tendency of peptides to be oxidized is intimately connected with their function and even their ability to exist in an oxidative environment. Here we report high-level theoretical studies that show that hydrogen bonding can alter the susceptibility of peptides to oxidation, with complexation to a hydrogen-bond acceptor facilitating oxidation, and vice versa, impacting the feasibility of a diverse range of biological processes. It can even provide an energetically viable mechanistic alternative to direct hydrogen-atom abstraction. We find that hydrogen bonding to representative reactive groups leads to a broad (≈400 kJ mol-1 ) spectrum of ionization energies in the case of model amide, thiol and phenol systems. While some of the oxidative processes at the extreme ends of the spectrum are energetically prohibitive, subtle environmental and solvent effects could potentially mitigate the situation, leading to a balance between hydrogen bonding and oxidative susceptibility.
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Affiliation(s)
- Bun Chan
- Graduate School of Engineering, Nagasaki University, Nagasaki, 852-8521, Japan
| | - Damian Moran
- School of Chemistry, University of Sydney, Sydney, NSW, 2006, Australia
| | - Christopher J Easton
- Research School of Chemistry, Australian National University, Canberra, ACT, 2601, Australia
| | - Leo Radom
- School of Chemistry, University of Sydney, Sydney, NSW, 2006, Australia
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27
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Papp D, Rovó P, Jákli I, Császár AG, Perczel A. Four faces of the interaction between ions and aromatic rings. J Comput Chem 2017; 38:1762-1773. [DOI: 10.1002/jcc.24816] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2017] [Revised: 04/05/2017] [Accepted: 04/06/2017] [Indexed: 02/06/2023]
Affiliation(s)
- Dóra Papp
- MTA-ELTE Complex Chemical Systems Research Group; H-1518 Budapest 112, P.O. Box 32 Hungary
- Laboratory of Molecular Structure and Dynamics; Institute of Chemistry, Eötvös Loránd University; Pázmány Péter sétány 1/A Budapest H-1117 Hungary
| | - Petra Rovó
- Department Chemie und Pharmazie; Ludwig-Maximilians-Universität München; Butenandstraße 5-11 Munich D-81377 Germany
| | - Imre Jákli
- MTA-ELTE Protein Modeling Research Group, Institute of Chemistry, Eötvös Loránd University; H-1518 Budapest 112, P.O. Box 32 Hungary
| | - Attila G. Császár
- MTA-ELTE Complex Chemical Systems Research Group; H-1518 Budapest 112, P.O. Box 32 Hungary
- Laboratory of Molecular Structure and Dynamics; Institute of Chemistry, Eötvös Loránd University; Pázmány Péter sétány 1/A Budapest H-1117 Hungary
| | - András Perczel
- MTA-ELTE Protein Modeling Research Group, Institute of Chemistry, Eötvös Loránd University; H-1518 Budapest 112, P.O. Box 32 Hungary
- Laboratory of Structural Chemistry and Biology; Institute of Chemistry, Eötvös Loránd University; Pázmány Péter sétány 1/A Budapest H-1117 Hungary
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28
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Mata RA, Suhm MA. Quantenchemische Methoden im Leistungsvergleich: Stimmt die Richtung noch? Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201611308] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Ricardo A. Mata
- Institut für Physikalische Chemie; Universität Göttingen; Tammannstraße 6 37077 Göttingen Deutschland
| | - Martin A. Suhm
- Institut für Physikalische Chemie; Universität Göttingen; Tammannstraße 6 37077 Göttingen Deutschland
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29
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Juanes M, Vogt N, Demaison J, León I, Lesarri A, Rudolph HD. Axial–equatorial isomerism and semiexperimental equilibrium structures of fluorocyclohexane. Phys Chem Chem Phys 2017; 19:29162-29169. [DOI: 10.1039/c7cp06135h] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Accuracy vs. computational effort: the mixed estimation method provides very accurate semiexperimental equilibrium structures, as illustrated by the subtle differences between axial/equatorial fluorocyclohexane.
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Affiliation(s)
- Marcos Juanes
- Departamento de Química Física y Química Inorgánica
- Facultad de Ciencias
- Universidad de Valladolid
- 47011 Valladolid
- Spain
| | - Natalja Vogt
- Section of Chemical Information Systems
- University of Ulm
- 89081 Ulm
- Germany
- Department of Chemistry
| | - Jean Demaison
- Section of Chemical Information Systems
- University of Ulm
- 89081 Ulm
- Germany
| | - Iker León
- Departamento de Química Física y Química Inorgánica
- Facultad de Ciencias
- Universidad de Valladolid
- 47011 Valladolid
- Spain
| | - Alberto Lesarri
- Departamento de Química Física y Química Inorgánica
- Facultad de Ciencias
- Universidad de Valladolid
- 47011 Valladolid
- Spain
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30
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Abstract
We introduce a general theoretical approach for the simulation of photochemical dynamics under the influence of circularly polarized light to explore the possibility of generating enantiomeric enrichment through polarized-light-selective photochemistry. The method is applied to the simulation of the photolysis of alanine, a prototype chiral amino acid. We show that a systematic enantiomeric enrichment can be obtained depending on the helicity of the circularly polarized light that induces the excited-state photochemistry of alanine. By analyzing the patterns of the photoinduced fragmentation of alanine we find an inducible enantiomeric enrichment up to 1.7%, which is also in good correspondence to the experimental findings. Our method is generally applicable to complex systems and might serve to systematically explore the photochemical origin of homochirality.
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Affiliation(s)
- Matthias Wohlgemuth
- Institute for Physical and Theoretical Chemistry, Julius Maximilians University Würzburg , Emil-Fischer-Str. 42, 97074 Würzburg, Germany
| | - Roland Mitrić
- Institute for Physical and Theoretical Chemistry, Julius Maximilians University Würzburg , Emil-Fischer-Str. 42, 97074 Würzburg, Germany
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31
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First-principles data set of 45,892 isolated and cation-coordinated conformers of 20 proteinogenic amino acids. Sci Data 2016; 3:160009. [PMID: 26881946 PMCID: PMC4755128 DOI: 10.1038/sdata.2016.9] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 01/15/2016] [Indexed: 11/24/2022] Open
Abstract
We present a structural data set of the 20 proteinogenic amino acids and their amino-methylated and acetylated (capped) dipeptides. Different protonation states of the backbone (uncharged and zwitterionic) were considered for the amino acids as well as varied side chain protonation states. Furthermore, we studied amino acids and dipeptides in complex with divalent cations (Ca2+, Ba2+, Sr2+, Cd2+, Pb2+, and Hg2+). The database covers the conformational hierarchies of 280 systems in a wide relative energy range of up to 4 eV (390 kJ/mol), summing up to a total of 45,892 stationary points on the respective potential-energy surfaces. All systems were calculated on equal first-principles footing, applying density-functional theory in the generalized gradient approximation corrected for long-range van der Waals interactions. We show good agreement to available experimental data for gas-phase ion affinities. Our curated data can be utilized, for example, for a wide comparison across chemical space of the building blocks of life, for the parametrization of protein force fields, and for the calculation of reference spectra for biophysical applications.
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32
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Vogt N, Demaison J, Cocinero EJ, Écija P, Lesarri A, Rudolph HD, Vogt J. The equilibrium molecular structures of 2-deoxyribose and fructose by the semiexperimental mixed estimation method and coupled-cluster computations. Phys Chem Chem Phys 2016; 18:15555-63. [PMID: 27212641 DOI: 10.1039/c6cp01842d] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The mixed estimation method yields very accurate equilibrium structures, as observed in deoxyribose and fructose.
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Affiliation(s)
- Natalja Vogt
- Section of Chemical Information Systems
- Faculty of Sciences
- University of Ulm
- 89069 Ulm
- Germany
| | - Jean Demaison
- Section of Chemical Information Systems
- Faculty of Sciences
- University of Ulm
- 89069 Ulm
- Germany
| | - Emilio J. Cocinero
- Departamento de Química Física
- Facultad de Ciencia y Tecnología
- Universidad del País Vasco (UPV-EHU)
- 48080 Bilbao
- Spain
| | - Patricia Écija
- Departamento de Química Física
- Facultad de Ciencia y Tecnología
- Universidad del País Vasco (UPV-EHU)
- 48080 Bilbao
- Spain
| | - Alberto Lesarri
- Departamento de Química Física y Química Inorgánica
- Facultad de Ciencias
- Universidad de Valladolid
- 47011 Valladolid
- Spain
| | - Heinz Dieter Rudolph
- Section of Chemical Information Systems
- Faculty of Sciences
- University of Ulm
- 89069 Ulm
- Germany
| | - Jürgen Vogt
- Section of Chemical Information Systems
- Faculty of Sciences
- University of Ulm
- 89069 Ulm
- Germany
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33
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Cukras J, Kauczor J, Norman P, Rizzo A, Rikken GLJA, Coriani S. A complex-polarization-propagator protocol for magneto-chiral axial dichroism and birefringence dispersion. Phys Chem Chem Phys 2016; 18:13267-79. [PMID: 27118603 DOI: 10.1039/c6cp01465h] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A schematic representation of magneto-chiral effects.
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Affiliation(s)
- Janusz Cukras
- Dipartimento di Scienze Chimiche e Farmaceutiche
- Università degli Studi di Trieste
- 34127 Trieste
- Italy
- Faculty of Chemistry
| | - Joanna Kauczor
- Department of Physics
- Chemistry and Biology
- Linköping University
- Linköping
- Sweden
| | - Patrick Norman
- Department of Physics
- Chemistry and Biology
- Linköping University
- Linköping
- Sweden
| | - Antonio Rizzo
- Consiglio Nazionale delle Ricerche – CNR
- Istituto per i Processi Chimico-Fisici
- IPCF-CNR
- Sede Secondaria di Pisa
- I-56124 Pisa
| | - Geert L. J. A. Rikken
- Laboratoire National des Champs Magnétiques Intenses
- UPR3228 CNRS/INSA/UJF/UPS
- Toulouse & Grenoble
- France
| | - Sonia Coriani
- Dipartimento di Scienze Chimiche e Farmaceutiche
- Università degli Studi di Trieste
- 34127 Trieste
- Italy
- Aarhus Institute of Advanced Studies
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34
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Piccardo M, Bloino J, Barone V. Generalized Vibrational Perturbation Theory for Rotovibrational Energies of Linear, Symmetric and Asymmetric Tops: Theory, Approximations, and Automated Approaches to Deal with Medium-to-Large Molecular Systems. INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY 2015; 115:948-982. [PMID: 26345131 PMCID: PMC4553754 DOI: 10.1002/qua.24931] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Revised: 04/03/2015] [Accepted: 04/08/2015] [Indexed: 06/05/2023]
Abstract
Models going beyond the rigid-rotor and the harmonic oscillator levels are mandatory for providing accurate theoretical predictions for several spectroscopic properties. Different strategies have been devised for this purpose. Among them, the treatment by perturbation theory of the molecular Hamiltonian after its expansion in power series of products of vibrational and rotational operators, also referred to as vibrational perturbation theory (VPT), is particularly appealing for its computational efficiency to treat medium-to-large systems. Moreover, generalized (GVPT) strategies combining the use of perturbative and variational formalisms can be adopted to further improve the accuracy of the results, with the first approach used for weakly coupled terms, and the second one to handle tightly coupled ones. In this context, the GVPT formulation for asymmetric, symmetric, and linear tops is revisited and fully generalized to both minima and first-order saddle points of the molecular potential energy surface. The computational strategies and approximations that can be adopted in dealing with GVPT computations are pointed out, with a particular attention devoted to the treatment of symmetry and degeneracies. A number of tests and applications are discussed, to show the possibilities of the developments, as regards both the variety of treatable systems and eligible methods.
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Affiliation(s)
- Matteo Piccardo
- Scuola Normale Superiore Piazza dei Cavalieri 7, I-56126, Pisa, Italy E-mail:
| | - Julien Bloino
- Scuola Normale Superiore Piazza dei Cavalieri 7, I-56126, Pisa, Italy E-mail: ; Consiglio Nazionale delle Ricerche, Istituto di Chimica dei Composti Organometallici (CNR-ICCOM) UOS di Pisa Via G. Moruzzi, 1, I-56124, Italy
| | - Vincenzo Barone
- Scuola Normale Superiore Piazza dei Cavalieri 7, I-56126, Pisa, Italy E-mail:
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35
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Császár AG, Demaison J, Rudolph HD. Equilibrium Structures of Three-, Four-, Five-, Six-, and Seven-Membered Unsaturated N-Containing Heterocycles. J Phys Chem A 2014; 119:1731-46. [DOI: 10.1021/jp5084168] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Attila G. Császár
- Laboratory
of Molecular Structure and Dynamics, Eötvös University, H-1117 Budapest,
Pázmány Péter sétány 1/A, Budapest, Hungary
- MTA-ELTE Research Group on Complex Chemical Systems, H-1518 Budapest 112, P.O. Box
32, Budapest, Hungary
| | - Jean Demaison
- Laboratoire
de Physique des Lasers, Atomes et Molécules, Université de Lille I, 59655 Villeneuve d’Ascq Cedex, France
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36
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Vogt N, Demaison J, Vogt J, Rudolph HD. Why it is sometimes difficult to determine the accurate position of a hydrogen atom by the semiexperimental method: Structure of molecules containing the OH or the CH3group. J Comput Chem 2014; 35:2333-42. [DOI: 10.1002/jcc.23758] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 09/23/2014] [Accepted: 09/27/2014] [Indexed: 11/09/2022]
Affiliation(s)
- Natalja Vogt
- Department of Theoretical Chemistry; Chemical Information Systems, University of Ulm; D-89069 Ulm Germany
- Department of Chemistry; Lomonosov Moscow State University; Moscow 119992 Russia
| | - Jean Demaison
- Department of Theoretical Chemistry; Chemical Information Systems, University of Ulm; D-89069 Ulm Germany
| | - Jürgen Vogt
- Department of Theoretical Chemistry; Chemical Information Systems, University of Ulm; D-89069 Ulm Germany
| | - Heinz Dieter Rudolph
- Department of Theoretical Chemistry; Chemical Information Systems, University of Ulm; D-89069 Ulm Germany
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37
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Sengupta A, Ramabhadran RO, Raghavachari K. Accurate and Computationally Efficient Prediction of Thermochemical Properties of Biomolecules Using the Generalized Connectivity-Based Hierarchy. J Phys Chem B 2014; 118:9631-43. [DOI: 10.1021/jp505544y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Arkajyoti Sengupta
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | | | - Krishnan Raghavachari
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
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38
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Barone V, Biczysko M, Bloino J, Puzzarini C. Accurate molecular structures and infrared spectra of trans-2,3-dideuterooxirane, methyloxirane, and trans-2,3-dimethyloxirane. J Chem Phys 2014; 141:034107. [PMID: 25053301 PMCID: PMC4612369 DOI: 10.1063/1.4887357] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Oxirane derivatives are the most used benchmarks for chiroptical spectroscopies in view of their small size and relative rigidity. The molecular structure, vibrational harmonic and anharmonic frequencies, and infrared intensities of the ground electronic states are analyzed in this paper. Equilibrium structure and harmonic force fields have been evaluated by means of high-level quantum-chemical calculations at the coupled-cluster level including single and double excitations together with a perturbative treatment of triples (CCSD(T)). Extrapolation to the complete basis-set limit as well as core-correlation effects have also been taken into account. Anharmonic contributions have been computed at the CCSD(T)/cc-pVTZ level for trans-2,3-dideuterooxirane. These data can serve as references to evaluate the accuracy of less expensive computational approaches rooted in the density functional theory (DFT). The latter have been used within hybrid CC/DFT approaches, which have been applied to simulate fully anharmonic infrared (IR) spectra. Finally, the best theoretical estimates of the equilibrium structures and vibrational wavenumbers are compared to the most accurate experimental data and show in all cases very good agreement, i.e., within 0.001 Å, 0.1 deg, 10 cm(-1), and 0.5 km mol(-1), for bond lengths, angles, wavenumbers, and IR intensities, respectively.
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Affiliation(s)
- Vincenzo Barone
- Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa, Italy
| | | | - Julien Bloino
- Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa, Italy
| | - Cristina Puzzarini
- Dipartimento di Chimica "Giacomo Ciamician," Università di Bologna, Via F. Selmi 2, I-40126 Bologna, Italy
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39
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Puzzarini C, Penocchio E, Biczysko M, Barone V. Molecular structure and spectroscopic signatures of acrolein: theory meets experiment. J Phys Chem A 2014; 118:6648-56. [PMID: 24842714 DOI: 10.1021/jp503672g] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
A comprehensive study of the molecular structure and IR spectrum of cis and trans acrolein has been performed by an integrated computational approach coupling methods rooted in the coupled-cluster ansatz and the density functional theory. From the one side, DFT anharmonic force fields allow us to determine very reliable semiexperimental structures for both isomers, which are in remarkable agreement with the geometries issuing from CCSD(T) computations accounting for the extrapolation to the complete basis set and core correlation. The same kind of coupled-cluster computations provide dipole moment, relative energies, and interconversion barrier in remarkable agreement with experiments. Finally, harmonic CCSD(T) results coupled to DFT evaluation of mechanical and electrical anharmonicity allow us, in the framework of second-order perturbative vibrational theory, to confirm most of the experimental assignments of IR spectra, and to suggest some additional interpretations for congested regions including fundamental bands together with overtones and combination bands.
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Affiliation(s)
- Cristina Puzzarini
- Dipartimento di Chimica "Giacomo Ciamician", Università di Bologna , Via Selmi 2, I-40126 Bologna, Italy
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40
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Karton A, Yu LJ, Kesharwani MK, Martin JML. Heats of formation of the amino acids re-examined by means of W1-F12 and W2-F12 theories. Theor Chem Acc 2014. [DOI: 10.1007/s00214-014-1483-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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41
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Tia M, Cunha de Miranda B, Daly S, Gaie-Levrel F, Garcia GA, Nahon L, Powis I. VUV photodynamics and chiral asymmetry in the photoionization of gas phase alanine enantiomers. J Phys Chem A 2014; 118:2765-79. [PMID: 24654892 DOI: 10.1021/jp5016142] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The valence shell photoionization of the simplest proteinaceous chiral amino acid, alanine, is investigated over the vacuum ultraviolet region from its ionization threshold up to 18 eV. Tunable and variable polarization synchrotron radiation was coupled to a double imaging photoelectron/photoion coincidence (i(2)PEPICO) spectrometer to produce mass-selected threshold photoelectron spectra and derive the state-selected fragmentation channels. The photoelectron circular dichroism (PECD), an orbital-sensitive, conformer-dependent chiroptical effect, was also recorded at various photon energies and compared to continuum multiple scattering calculations. Two complementary vaporization methods-aerosol thermodesorption and a resistively heated sample oven coupled to an adiabatic expansion-were applied to promote pure enantiomers of alanine into the gas phase, yielding neutral alanine with different internal energy distributions. A comparison of the photoelectron spectroscopy, fragmentation, and dichroism measured for each of the vaporization methods was rationalized in terms of internal energy and conformer populations and supported by theoretical calculations. The analytical potential of the so-called PECD-PICO detection technique-where the electron spectroscopy and circular dichroism can be obtained as a function of mass and ion translational energy-is underlined and applied to characterize the origin of the various species found in the experimental mass spectra. Finally, the PECD findings are discussed within an astrochemical context, and possible implications regarding the origin of biomolecular asymmetry are identified.
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Affiliation(s)
- Maurice Tia
- Synchrotron SOLEIL, l'Orme des Merisiers, Saint Aubin BP 48, 91192 Gif sur Yvette Cedex, France
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42
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Braga CB, Ducati LC, Tormena CF, Rittner R. Conformational analysis and intramolecular interactions of L-proline methyl ester and its N-acetylated derivative through spectroscopic and theoretical studies. J Phys Chem A 2014; 118:1748-58. [PMID: 24533966 DOI: 10.1021/jp5007632] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This work reports a detailed study regarding the conformational preferences of L-proline methyl ester (ProOMe) and its N-acetylated derivative (AcProOMe) to elucidate the effects that rule their behaviors, through nuclear magnetic resonance (NMR) and infrared (IR) spectroscopies combined with theoretical calculations. These compounds do not present a zwitterionic form in solution, simulating properly amino acid residues in biological media, in a way closer than amino acids in the gas phase. Experimental (3)JHH coupling constants and infrared data showed excellent agreement with theoretical calculations, indicating no variations in conformer populations on changing solvents. Natural bond orbital (NBO) results showed that hyperconjugative interactions are responsible for the higher stability of the most populated conformer of ProOMe, whereas for AcProOMe both hyperconjugative and steric effects rule its conformational equilibrium.
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Affiliation(s)
- Carolyne B Braga
- Physical Organic Chemistry Laboratory, Chemistry Institute, University of Campinas , 13083-970 Campinas, SP, Brazil
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43
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Puzzarini C, Biczysko M, Barone V, Largo L, Peña I, Cabezas C, Alonso JL. Accurate Characterization of the Peptide Linkage in the Gas Phase: A Joint Quantum-Chemical and Rotational Spectroscopy Study of the Glycine Dipeptide Analogue. J Phys Chem Lett 2014; 5:534-540. [PMID: 26276605 DOI: 10.1021/jz402744a] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Accurate structures of aminoacids in the gas phase have been obtained by joint microwave and quantum-chemical investigations. However, the structure and conformational behavior of α-aminoacids once incorporated into peptide chains are completely different and have not yet been characterized with the same accuracy. To fill this gap, we present here an accurate characterization of the simplest dipeptide analogue (N-acetyl-glycinamide) involving peptidic bonds. State-of-the-art quantum-chemical computations are complemented by a comprehensive study of the rotational spectrum using a combination of Fourier transform microwave spectroscopy with laser ablation. The coexistence of the C7 and C5 conformers has been proved and energetically as well as spectroscopically characterized. This joint theoretical-experimental investigation demonstrated the feasibility of obtaining accurate structures for flexible small biomolecules, thus paving the route to the elucidation of the inherent behavior of peptides.
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Affiliation(s)
- Cristina Puzzarini
- †Dipartimento di Chimica "Giacomo Ciamician", Università di Bologna, Via F. Selmi 2, 40126 Bologna, Italy
| | | | - Vincenzo Barone
- ‡Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa, Italy
| | - Laura Largo
- §Grupo de Espectroscopía Molecular (GEM), Edificio Quifima, Laboratorios de Espectroscopia y Bioespectroscopia, Parque Científico UVa, Unidad Asociada CSIC, Universidad de Valladolid, S-47005 Valladolid, Spain
| | - Isabel Peña
- §Grupo de Espectroscopía Molecular (GEM), Edificio Quifima, Laboratorios de Espectroscopia y Bioespectroscopia, Parque Científico UVa, Unidad Asociada CSIC, Universidad de Valladolid, S-47005 Valladolid, Spain
| | - Carlos Cabezas
- §Grupo de Espectroscopía Molecular (GEM), Edificio Quifima, Laboratorios de Espectroscopia y Bioespectroscopia, Parque Científico UVa, Unidad Asociada CSIC, Universidad de Valladolid, S-47005 Valladolid, Spain
| | - José Luis Alonso
- §Grupo de Espectroscopía Molecular (GEM), Edificio Quifima, Laboratorios de Espectroscopia y Bioespectroscopia, Parque Científico UVa, Unidad Asociada CSIC, Universidad de Valladolid, S-47005 Valladolid, Spain
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44
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Demaison J, Császár AG, Groner P, Rudolph HD, Craig NC. Semiexperimental Equilibrium Structures for cis, cis- and trans, trans-1,4-Difluorobutadiene by the Mixed Estimation Method and Definitive Relative Energies of the Isomers. J Phys Chem A 2013; 117:13166-75. [DOI: 10.1021/jp4098183] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Jean Demaison
- Laboratoire
de Physique des Lasers, Atomes et Molécules, Université de Lille 1, 59655 Villeneuve d’Ascq Cedex, France
| | - Attila G. Császár
- Laboratory of Molecular Structure and Dynamics,
Institute of Chemistry, Eötvös University, Pázmány
Péter sétány 1/A, H-1117 Budapest, Hungary
- MTA-ELTE
Research Group on Complex Chemical Systems, P.O. Box
32, H-1518 Budapest, Hungary
| | - Peter Groner
- Department of Chemistry, University of Missouri—Kansas City, Kansas City, Missouri 64110-2499, United States
| | | | - Norman C. Craig
- Department of Chemistry and Biochemistry, Oberlin College, Oberlin, Ohio 44074, United States
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45
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Rudolph HD, Demaison J, Császár AG. Accurate determination of the deformation of the benzene ring upon substitution: equilibrium structures of benzonitrile and phenylacetylene. J Phys Chem A 2013; 117:12969-82. [PMID: 24160689 DOI: 10.1021/jp408208s] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Accurate equilibrium, re, structures of the monosubstituted benzene molecules benzonitrile, C6H5CN, and phenylacetylene, C6H5CCH, have been determined using two different, to some extent complementary techniques. The semiexperimental, r(e)(SE), structural parameters are the result of a least-squares fit to equilibrium rotational constants derived from experimental effective ground-state rotational constants and rovibrational corrections based principally on an ab initio cubic force field. The composite ab initio Born-Oppenheimer, r(e)(BO), structural parameters are obtained from frozen-core and all-electron MP2 and the CCSD(T) geometry optimizations using Gaussian basis sets up to quintuple-zeta quality. The DFT(B3LYP) method, with two different Gaussian basis sets, 6-31G* and 6-311+G(3df,2pd), was used to calculate the cubic force field employed during the r(e)(SE) structure determination. With the 6-31G* basis set, the error of the rovibrational correction is to a large extent random, whereas with the 6-311+G(3df,2pd) basis set it is mainly systematic. As shown here, systematic errors do not have a significant effect on the accuracy of the derived structure; the quality of the structural fit, however, is sensitive to the true accuracy of the ground-state rotational constants. An even more important general conclusion of this study is that the addition of extra rotational constants from multisubstituted species does not seem to improve the accuracy of the r(e)(SE) structures, quite in contrast to the highly desirable availability of data corresponding to all singly substituted species.
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46
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Puzzarini C, Biczysko M, Barone V, Peña I, Cabezas C, Alonso JL. Accurate molecular structure and spectroscopic properties of nucleobases: a combined computational-microwave investigation of 2-thiouracil as a case study. Phys Chem Chem Phys 2013; 15:16965-75. [PMID: 24002739 PMCID: PMC4596004 DOI: 10.1039/c3cp52347k] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The computational composite scheme purposely set up for accurately describing the electronic structure and spectroscopic properties of small biomolecules has been applied to the first study of the rotational spectrum of 2-thiouracil. The experimental investigation was made possible thanks to the combination of the laser ablation technique with Fourier transform microwave spectrometers. The joint experimental-computational study allowed us to determine the accurate molecular structure and spectroscopic properties of the title molecule, but more importantly, it demonstrates a reliable approach for the accurate investigation of isolated small biomolecules.
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Affiliation(s)
- Cristina Puzzarini
- Dipartimento di Chimica "Giacomo Ciamician", Università di Bologna, Via F. Selmi 2, I-40126 Bologna, Italy.
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47
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Demaison J, Rudolph HD, Császár AG. Deformation of the benzene ring upon fluorination: equilibrium structures of all fluorobenzenes. Mol Phys 2013. [DOI: 10.1080/00268976.2013.793843] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Jean Demaison
- a Laboratoire de Physique des Lasers, Atomes et Molécules , Université de Lille I , France
| | | | - Attila G. Császár
- c Laboratory of Molecular Structure and Dynamics, Institute of Chemistry , Eötvös University , Budapest , Hungary
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48
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Nunes CM, Lapinski L, Fausto R, Reva I. Near-IR laser generation of a high-energy conformer of L-alanine and the mechanism of its decay in a low-temperature nitrogen matrix. J Chem Phys 2013; 138:125101. [DOI: 10.1063/1.4795823] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
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49
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Abstract
Rotational spectroscopy is known to be a technique that is widely used to infer information on molecular structure and dynamics. In the last few decades, its role in the field of atmospheric and astrophysical investigations has rapidly grown. However, several are the challenging aspects in rotational spectroscopy, since the detection and analysis of spectra as well as interpretation of obtained results are not at all straightforward. Quantum chemistry has reached such an accuracy that can be used to disentangle these challenging situations by guiding the experimental investigation, assisting in the determination of the spectroscopic parameters, and extracting information of chemical interest. This perspective provides an overview of the theoretical background and computational requirements needed for the accurate evaluation of the spectroscopic parameters of relevance to rotational spectroscopy. The role of theory in guiding and supporting experiment is detailed through a few examples, and the interplay of experiment and theory is discussed in terms of the information of physical and chemical interest that can be derived.
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Affiliation(s)
- Cristina Puzzarini
- Dipartimento di Chimica Giacomo Ciamician, Università di Bologna, Via Selmi 2, I-40126 Bologna, Italy.
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50
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Bazsó G, Najbauer EE, Magyarfalvi G, Tarczay G. Near-Infrared Laser Induced Conformational Change of Alanine in Low-Temperature Matrixes and the Tunneling Lifetime of Its Conformer VI. J Phys Chem A 2013; 117:1952-62. [DOI: 10.1021/jp400196b] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Gábor Bazsó
- Laboratory of Molecular
Spectroscopy, Institute of Chemistry, Eötvös University, P.O. Box 32, H-1518, Budapest 112, Hungary
| | - Eszter E. Najbauer
- Laboratory of Molecular
Spectroscopy, Institute of Chemistry, Eötvös University, P.O. Box 32, H-1518, Budapest 112, Hungary
| | - Gábor Magyarfalvi
- Laboratory of Molecular
Spectroscopy, Institute of Chemistry, Eötvös University, P.O. Box 32, H-1518, Budapest 112, Hungary
| | - György Tarczay
- Laboratory of Molecular
Spectroscopy, Institute of Chemistry, Eötvös University, P.O. Box 32, H-1518, Budapest 112, Hungary
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