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Pagacz-Kostrzewa M, Szaniawska W, Wierzejewska M. NIR and UV induced transformations of indazole-3-carboxylic acid isolated in low temperature matrices. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2023; 290:122283. [PMID: 36586171 DOI: 10.1016/j.saa.2022.122283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Accepted: 12/26/2022] [Indexed: 06/17/2023]
Abstract
The molecular structure and NIR and UV induced phototransformations of indazole-3-carboxylic acid were studied in low temperature argon and nitrogen matrices by FTIR spectroscopy and B3LYP/6-311++G(2d,2p) calculations. Eleven minima of IC were located on the S0 potential energy surface. The three most stable structures were detected experimentally in both matrices after deposition. Upon NIR irradiation a dominant process was rotamerization within the carboxylic group leading to changes in the population of the trans 1HIC1 and cis 1HIC2 forms. In turn, at UV irradiation at λ = 260 nm two new tautomers (2HIC2 and 2HIC3) were generated indicating that the hydrogen atom transfer in pyrazole ring took place. Based on the obtained kinetic curves, differences in the phototransformation rates in different matrices were indicated.
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Affiliation(s)
- M Pagacz-Kostrzewa
- Faculty of Chemistry, University of Wrocław, F. Joliot-Curie 14, 50-383 Wrocław, Poland.
| | - W Szaniawska
- Faculty of Chemistry, University of Wrocław, F. Joliot-Curie 14, 50-383 Wrocław, Poland
| | - M Wierzejewska
- Faculty of Chemistry, University of Wrocław, F. Joliot-Curie 14, 50-383 Wrocław, Poland
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Lopes Jesus AJ, de Lucena Júnior JR, Fausto R, Reva I. Infrared Spectra and Phototransformations of meta-Fluorophenol Isolated in Argon and Nitrogen Matrices. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27238248. [PMID: 36500356 PMCID: PMC9735537 DOI: 10.3390/molecules27238248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/22/2022] [Revised: 11/18/2022] [Accepted: 11/21/2022] [Indexed: 11/29/2022]
Abstract
Monomers of meta-fluorophenol (mFP) were trapped from the gas phase into cryogenic argon and nitrogen matrices. The estimated relative energies of the two conformers are very close, and in the gas phase they have nearly equal populations. Due to the similarity of their structures (they only differ in the orientation of the OH group), the two conformers have also similar predicted vibrational signatures, which makes the vibrational characterization of the individual rotamers challenging. In the present work, it has been established that in an argon matrix only the most stable trans conformer of mFP exists (the OH group pointing away from the fluorine atom). On the other hand, the IR spectrum of mFP in a nitrogen matrix testifies to the simultaneous presence in this matrix of both the trans conformer and of the higher-energy cis conformer (the OH group pointing toward the fluorine atom), which is stabilized by interaction with the matrix gas host. We found that the exposition of the cryogenic N2 matrix to the Globar source of the infrared spectrometer affects the conformational populations. By collecting experimental spectra, either in the full mid-infrared range or only in the range below 2200 cm-1, we were able to reliably distinguish two sets of experimental bands originating from individual conformers. A comparison of the two sets of experimental bands with computed infrared spectra of the conformers allowed, for the first time, the unequivocal vibrational identification of each of them. The joint implementation of computational vibrational spectroscopy and matrix-isolation infrared spectroscopy proved to be a very accurate method of structural analysis. Some mechanistic insights into conformational isomerism (the quantum tunneling of hydrogen atom and vibrationally-induced conformational transformations) have been addressed. Finally, we also subjected matrix-isolated mFP to irradiations with UV light, and the phototransformations observed in these experiments are also described.
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Affiliation(s)
- A. J. Lopes Jesus
- CQC-IMS, Faculty of Pharmacy, University of Coimbra, 3004-295 Coimbra, Portugal
- Correspondence: (A.J.L.J.); (I.R.)
| | | | - Rui Fausto
- CQC-IMS, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
| | - Igor Reva
- CQC-IMS, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
- CIEPQPF, Department of Chemical Engineering, University of Coimbra, 3030-790 Coimbra, Portugal
- Correspondence: (A.J.L.J.); (I.R.)
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Fausto R, Ildiz GO, Nunes CM. IR-induced and tunneling reactions in cryogenic matrices: the (incomplete) story of a successful endeavor. Chem Soc Rev 2022; 51:2853-2872. [PMID: 35302145 DOI: 10.1039/d1cs01026c] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
In this article, IR-induced and tunneling-driven reactions observed in cryogenic matrices are described in a historical perspective, the entangling of the two types of processes being highlighted. The story of this still ongoing fascinating scientific endeavor is presented here following closely our own involvement in the field for more than 30 years, and thus focuses mostly on our work. It is, because of this reason, also an incomplete story. Nevertheless, it considers a large range of examples, from very selective IR-induced conformational isomerizations to IR-induced bond-breaking/bond-forming reactions and successful observations of rare heavy atom tunneling processes. As a whole, this article provides a rather general overview of the major progress achieved in the field.
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Affiliation(s)
- Rui Fausto
- CQC-IMS, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal.
| | - Gulce O Ildiz
- CQC-IMS, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal. .,Department of Physics, Faculty of Sciences and Letters, Istanbul Kultur University, 34158 Bakirkoy, Istanbul, Turkey
| | - Cláudio M Nunes
- CQC-IMS, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal.
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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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Lopes Jesus AJ, Fausto R, Reva I. Conformational Space, IR-Induced, and UV-Induced Chemistry of Carvacrol Isolated in a Low-Temperature Argon Matrix. J Phys Chem A 2021; 125:8215-8229. [PMID: 34506137 DOI: 10.1021/acs.jpca.1c05907] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
In this work, monomers of carvacrol (5-isopropyl-2-methylphenol), a natural monoterpene exhibiting wide range bioactivity, were trapped in a cryogenic argon matrix and characterized by infrared spectroscopy, while quantum chemical calculations at the B3LYP and MP2 levels were employed to characterize the conformational landscape of the isolated molecule. Four conformers have been localized on the potential energy surface, and the factors accounting for their relative stability were analyzed. The two most stable conformers of carvacrol, differing in the relative orientation of the isopropyl group and both having the OH group pointing away from the vicinal methyl fragment, were identified in the cryomatrix for the first time. The individual spectral signatures of the two conformers were distinguished based on the change in their relative abundance induced by exposing the matrix to broadband infrared light. Matrix-isolated carvacrol was also irradiated with broadband UV light (λ > 200 nm), which resulted in the cleavage of the OH group. Recombination of the released H atom at the ortho- or para-position of the ring resulted in the formation of alkyl-substituted cyclohexadienones. These were found to undergo subsequent valence and open-ring isomerizations, leading, respectively, to the formation of a Dewar isomer and open-chain conjugated ketenes. Decarbonylation of the photoproducts was also observed for longer irradiation times. A mechanistic analysis of the observed photochemical transformations is presented.
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Affiliation(s)
- A J Lopes Jesus
- University of Coimbra, CQC, Faculty of Pharmacy, 3004-295 Coimbra, Portugal
| | - Rui Fausto
- University of Coimbra, CQC, Department of Chemistry, 3004-535 Coimbra, Portugal
| | - Igor Reva
- University of Coimbra, CQC, Department of Chemistry, 3004-535 Coimbra, Portugal.,University of Coimbra, CIEPQPF, Department of Chemical Engineering, 3030-790 Coimbra, Portugal
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Feldman VI, Ryazantsev SV, Kameneva SV. Matrix isolation in laboratory astrochemistry: state-of-the-art, implications and perspective. RUSSIAN CHEMICAL REVIEWS 2021. [DOI: 10.1070/rcr4995] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Nunes CM, Pereira NAM, Reva I, Amado PSM, Cristiano MLS, Fausto R. Bond-Breaking/Bond-Forming Reactions by Vibrational Excitation: Infrared-Induced Bidirectional Tautomerization of Matrix-Isolated Thiotropolone. J Phys Chem Lett 2020; 11:8034-8039. [PMID: 32869645 DOI: 10.1021/acs.jpclett.0c02272] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Infrared vibrational excitation is a promising approach for gaining exceptional control of chemical reactions, in ways that cannot be attained via thermal or electronic excitation. Here, we report an unprecedented example of a bond-breaking/bond-forming reaction by vibrational excitation under matrix isolation conditions. Thiotropolone monomers were isolated in cryogenic argon matrices and characterized by infrared spectroscopy and vibrational computations (harmonic and anharmonic). Narrowband near-infrared irradiations tuned at frequencies of first CH stretching overtone (5940 cm-1) or combination modes (5980 cm-1) of the OH tautomer, the sole form of the compound that exists in the as-deposited matrices, led to its conversion into the SH tautomer. The tautomerization in the reverse direction was achieved by vibrational excitation of the SH tautomer with irradiation at 5947 or 5994 cm-1, corresponding to the frequencies of its CH stretching combination and overtone modes. This pioneer demonstration of bidirectional hydroxyl ↔ thiol tautomerization controlled by vibrational excitation creates prospects for new advances in vibrationally induced chemistry.
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Affiliation(s)
- Cláudio M Nunes
- University of Coimbra, CQC, Department of Chemistry, 3004-535 Coimbra, Portugal
| | - Nelson A M Pereira
- University of Coimbra, CQC, Department of Chemistry, 3004-535 Coimbra, Portugal
| | - Igor Reva
- University of Coimbra, CQC, Department of Chemistry, 3004-535 Coimbra, Portugal
| | - Patrícia S M Amado
- Centre of Marine Sciences, CCMAR, and Department of Chemistry and Pharmacy, University of Algarve, 8005-139 Faro, Portugal
| | - Maria L S Cristiano
- Centre of Marine Sciences, CCMAR, and Department of Chemistry and Pharmacy, University of Algarve, 8005-139 Faro, Portugal
| | - Rui Fausto
- University of Coimbra, CQC, Department of Chemistry, 3004-535 Coimbra, Portugal
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Lang SM, Bernhardt TM, Bakker JM, Barnett RN, Landman U. Energetic Stabilization of Carboxylic Acid Conformers by Manganese Atoms and Clusters. J Phys Chem A 2020; 124:4990-4997. [DOI: 10.1021/acs.jpca.0c03315] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Sandra M. Lang
- Institute of Surface Chemistry and Catalysis, University of Ulm, Albert-Einstein-Allee 47, 89069 Ulm, Germany
| | - Thorsten M. Bernhardt
- Institute of Surface Chemistry and Catalysis, University of Ulm, Albert-Einstein-Allee 47, 89069 Ulm, Germany
| | - Joost M. Bakker
- Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands
| | - Robert N. Barnett
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0430, United States
| | - Uzi Landman
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0430, United States
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Nunes CM, Reva I, Fausto R. Conformational isomerizations triggered by vibrational excitation of second stretching overtones. Phys Chem Chem Phys 2019; 21:24993-25001. [PMID: 31710324 DOI: 10.1039/c9cp05070a] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Vibrational excitation using frequency-tunable IR laser light has been developed as a powerful tool for selective manipulation of molecular conformations. In this methodology, vibrational excitation has been typically applied to the first stretching overtones (∼80 kJ mol-1) but also to the fundamental modes (∼40 kJ mol-1). Here, we demonstrate that selective conformational isomerizations are also achieved using excitation to second stretching overtones (∼120 kJ mol-1). The extremely weak absorptions of the second stretching overtones of molecules isolated in low-temperature matrices were measured for the first time; here using three prototype molecules: hydroxyacetone (HA), glycolic acid (GAc) and glycolamide (GAm). Benchmarking of computed anharmonic IR spectra showed that the B3LYP/SNSD method provides the best agreement with experimental frequencies of the ν(OH), 2ν(OH) and 3ν(OH) modes for the studied molecules in argon matrices. Selective irradiation at the 3ν(OH) frequencies (9850-10 500 cm-1) of HA, GAc and GAm monomers in argon matrices at 15 K successfully triggers their conformational isomerization. These results open the door to extend control over conformations separated by higher barriers and to induce other transformations not energetically accessible by excitation to the fundamental or first stretching overtone modes.
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Affiliation(s)
- Cláudio M Nunes
- CQC, Department of Chemistry, University of Coimbra, 3004-535, Coimbra, Portugal.
| | - Igor Reva
- CQC, Department of Chemistry, University of Coimbra, 3004-535, Coimbra, Portugal.
| | - Rui Fausto
- CQC, Department of Chemistry, University of Coimbra, 3004-535, Coimbra, Portugal.
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11
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Nowak MJ, Reva I, Lopes Jesus AJ, Lapinski L, Fausto R. UV-promoted radical formation, and near-IR-induced and spontaneous conformational isomerization in monomeric 9-methylguanine isolated in low-temperature Ar matrices. Phys Chem Chem Phys 2019; 21:22857-22868. [PMID: 31599896 DOI: 10.1039/c9cp04487f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Three low-energy isomers of 9-methylguanine, the amino-oxo (AO) form and two amino-hydroxy (AH1 and AH2) conformers, were trapped from the gas phase into low-temperature argon matrices. The AH1 and AH2 isomers, differing in the orientation of the OH group, were found to transform into each other upon excitation with near-IR light. The population of the AO form of the compound was not changed upon any near-IR irradiation of the matrix samples. Using monochromatic near-IR light, generated by a frequency-tunable laser source, it was possible to selectively induce the AH1 → AH2 or AH2 → AH1 conversion. Photoreversibility of this conformational transformation was then demonstrated. Exposure of matrix-isolated monomers of 9-methylguanine to broadband near-IR light also led to conformational conversions within the amino-hydroxy tautomeric form; the final stage of this process was always the same photostationary state independent of the initial ratio of AH1 and AH2 populations. Spontaneous conformational conversion, transforming the higher-energy AH2 form into the lower-energy AH1 isomer, was observed for matrix-isolated monomers of 9-methylguanine kept in the dark. The mechanism of this process must rely on quantum tunneling of the light hydrogen atom. Irradiation of matrix-isolated 9-methylguanine with UV laser light at λ = 288 or 285 nm led to a substantial consumption of the two AH forms, while the amount of AO isomer remained unchanged. On the other hand, a decrease in the population of the AO isomer occurred upon excitations at shorter wavelengths, λ = 280 or 275 nm. The spectral changes observed after UV-irradiation suggest the generation (and stabilization in the matrix) of a radical species, resulting from the photocleavage of the O-H or N1-H bonds, in the AH or AO isomer, respectively.
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Affiliation(s)
- Maciej J Nowak
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland.
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12
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Ahokas JM, Kosendiak I, Krupa J, Wierzejewska M, Lundell J. Raman spectroscopy of glycolic acid complexes with N2. J Mol Struct 2019. [DOI: 10.1016/j.molstruc.2019.01.080] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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13
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Lopes Jesus AJ, Nunes CM, Reva I, Pinto SMV, Fausto R. Effects of Entangled IR Radiation and Tunneling on the Conformational Interconversion of 2-Cyanophenol. J Phys Chem A 2019; 123:4396-4405. [DOI: 10.1021/acs.jpca.9b01382] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- A. J. Lopes Jesus
- CQC, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
- CQC, Faculty of Pharmacy, University of Coimbra, 3004-295 Coimbra, Portugal
| | - Cláudio M. Nunes
- CQC, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
| | - I. Reva
- CQC, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
| | - Sandra M. V. Pinto
- CQC, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
- Scuola Normale Superiore, Piazza dei Cavalieri, 7, I-56124 Pisa, Italy
| | - R. Fausto
- CQC, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
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Lapinski L, Reva I, Rostkowska H, Lopes Jesus AJ, Vieira Pinto SM, Fausto R, Nowak MJ. Conformational Isomerizations by Rotation around C–C or C–N Bonds: A Comparative Study on Matrix-Isolated Glycolamide and N-Hydroxyurea Excited with Near-IR Laser Light. J Phys Chem A 2019; 123:3831-3839. [DOI: 10.1021/acs.jpca.9b01992] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Leszek Lapinski
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland
| | - Igor Reva
- CQC, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
| | - Hanna Rostkowska
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland
| | - A. J. Lopes Jesus
- CQC, Faculty of Pharmacy, University of Coimbra, 3004-295 Coimbra, Portugal
| | - Sandra M. Vieira Pinto
- CQC, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
- Scuola Normale Superiore, Piazza dei Cavalieri, 7, I-56124 Pisa, Italy
| | - Rui Fausto
- CQC, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
| | - Maciej J. Nowak
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland
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15
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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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Góbi S, Nunes CM, Reva I, Tarczay G, Fausto R. S–H rotamerizationviatunneling in a thiol form of thioacetamide. Phys Chem Chem Phys 2019; 21:17063-17071. [DOI: 10.1039/c9cp03417j] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Rotamerization of the S–H groupviahydrogen tunneling is reported for the first time.
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Affiliation(s)
- Sándor Góbi
- CQC
- Department of Chemistry
- University of Coimbra
- Coimbra
- Portugal
| | | | - Igor Reva
- CQC
- Department of Chemistry
- University of Coimbra
- Coimbra
- Portugal
| | - György Tarczay
- Laboratory of Molecular Spectroscopy
- Institute of Chemistry
- ELTE Eötvös Loránd University
- H-1518 Budapest
- Hungary
| | - Rui Fausto
- CQC
- Department of Chemistry
- University of Coimbra
- Coimbra
- Portugal
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17
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Góbi S, Reva I, Csonka IP, M. Nunes C, Tarczay G, Fausto R. Selective conformational control by excitation of NH imino vibrational antennas. Phys Chem Chem Phys 2019; 21:24935-24949. [DOI: 10.1039/c9cp05370k] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We provide experimental evidence for the occurrence of selective and reversible conformational control over the SH group by vibrational excitation of remote NH groups. Using an imino group that acts as a molecular antenna has no precedents.
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Affiliation(s)
- Sándor Góbi
- CQC
- Department of Chemistry
- University of Coimbra
- Coimbra
- Portugal
| | - Igor Reva
- CQC
- Department of Chemistry
- University of Coimbra
- Coimbra
- Portugal
| | - István Pál Csonka
- MTA-ELTE Lendület Laboratory Astrochemistry Research Group
- Institute of Chemistry
- ELTE Eötvös Loránd University
- H–1518 Budapest
- Hungary
| | | | - György Tarczay
- MTA-ELTE Lendület Laboratory Astrochemistry Research Group
- Institute of Chemistry
- ELTE Eötvös Loránd University
- H–1518 Budapest
- Hungary
| | - Rui Fausto
- CQC
- Department of Chemistry
- University of Coimbra
- Coimbra
- Portugal
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18
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Linden MM, Wagner JP, Bernhardt B, Bartlett MA, Allen WD, Schreiner PR. Intricate Conformational Tunneling in Carbonic Acid Monomethyl Ester. J Phys Chem Lett 2018; 9:1663-1667. [PMID: 29544243 DOI: 10.1021/acs.jpclett.8b00295] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Disentangling internal and external effects is a key requirement for understanding conformational tunneling processes. Here we report the s- trans/ s- cis tunneling rotamerization of carbonic acid monomethyl ester (1) under matrix isolation conditions and make comparisons to its parent carbonic acid (3). The observed tunneling rate of 1 is temperature-independent in the 3-20 K range and accelerates when using argon instead of neon as the matrix material. The methyl group increases the effective half life (τeff) of the energetically disfavored s- trans-conformer from 3-5 h for 3 to 11-13 h for 1. Methyl group deuteration slows the rotamerization further (τeff ≈ 35 h). CCSD(T)/cc-pVQZ//MP2/aug-cc-pVTZ computations of the tunneling probability suggest that the rate should be almost unaffected by methyl substitution or its deuteration. Thus the observed relative rates are puzzling, and they disagree with previous explanations involving fast vibrational relaxation after the tunneling event facilitated by the alkyl rotor.
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Affiliation(s)
- Michael M Linden
- Institute of Organic Chemistry , Justus Liebig University , Heinrich-Buff-Ring 17 , 35392 Giessen , Germany
| | - J Philipp Wagner
- Institute of Organic Chemistry , Justus Liebig University , Heinrich-Buff-Ring 17 , 35392 Giessen , Germany
| | - Bastian Bernhardt
- Institute of Organic Chemistry , Justus Liebig University , Heinrich-Buff-Ring 17 , 35392 Giessen , Germany
| | - Marcus A Bartlett
- Center for Computational Quantum Chemistry and Department of Chemistry , University of Georgia , Athens , Georgia 30602 , United States
| | - Wesley D Allen
- Center for Computational Quantum Chemistry and Department of Chemistry , University of Georgia , Athens , Georgia 30602 , United States
| | - Peter R Schreiner
- Institute of Organic Chemistry , Justus Liebig University , Heinrich-Buff-Ring 17 , 35392 Giessen , Germany
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19
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Lopes Jesus AJ, M. Nunes C, Fausto R, Reva I. Conformational control over an aldehyde fragment by selective vibrational excitation of interchangeable remote antennas. Chem Commun (Camb) 2018; 54:4778-4781. [DOI: 10.1039/c8cc01052h] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We apply vibrational antennas (OH or NH2 group) to achieve unprecedented conformational control over the heavy aldehyde fragment in 2-formyl-2H-azirine, using selective vibrational excitations of the OH or NH2 stretching overtones and combination modes.
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Affiliation(s)
| | | | - Rui Fausto
- CQC
- Department of Chemistry
- University of Coimbra
- Coimbra
- Portugal
| | - Igor Reva
- CQC
- Department of Chemistry
- University of Coimbra
- Coimbra
- Portugal
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20
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Rostkowska H, Lapinski L, Nowak MJ. Hydrogen-atom tunneling through a very high barrier; spontaneous thiol → thione conversion in thiourea isolated in low-temperature Ar, Ne, H2and D2matrices. Phys Chem Chem Phys 2018; 20:13994-14002. [DOI: 10.1039/c8cp01703d] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Hydrogen-atom tunneling in thiourea involves breaking of the S–H chemical bond and the formation of a new N–H bond.
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Affiliation(s)
- Hanna Rostkowska
- Institute of Physics
- Polish Academy of Sciences
- 02-668 Warsaw
- Poland
| | - Leszek Lapinski
- Institute of Physics
- Polish Academy of Sciences
- 02-668 Warsaw
- Poland
| | - Maciej J. Nowak
- Institute of Physics
- Polish Academy of Sciences
- 02-668 Warsaw
- Poland
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21
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Grimme S, Schreiner PR. Computerchemie: das Schicksal aktueller Methoden und zukünftige Herausforderungen. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201709943] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Stefan Grimme
- Mulliken Center for Theoretical Chemistry; Universität Bonn; Beringstraße 4 53115 Bonn Deutschland
| | - Peter R. Schreiner
- Institut für Organische Chemie; Justus-Liebig-Universität; Heinrich-Buff-Ring 17 35392 Gießen Deutschland
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22
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Grimme S, Schreiner PR. Computational Chemistry: The Fate of Current Methods and Future Challenges. Angew Chem Int Ed Engl 2017; 57:4170-4176. [PMID: 29105929 DOI: 10.1002/anie.201709943] [Citation(s) in RCA: 106] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Indexed: 11/12/2022]
Abstract
"Where do we go from here?" is the underlying question regarding the future (perhaps foreseeable) developments in computational chemistry. Although this young discipline has already permeated practically all of chemistry, it is likely to become even more powerful with the rapid development of computational hard- and software.
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Affiliation(s)
- Stefan Grimme
- Mulliken Center for Theoretical Chemistry, University of Bonn, Beringstr. 4, 53115, Bonn, Germany
| | - Peter R Schreiner
- Institute of Organic Chemistry, Justus-Liebig University, Heinrich-Buff-Ring 17, 35392, Giessen, Germany
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23
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Ryazantsev SV, Feldman VI, Khriachtchev L. Conformational Switching of HOCO Radical: Selective Vibrational Excitation and Hydrogen-Atom Tunneling. J Am Chem Soc 2017. [DOI: 10.1021/jacs.7b02605] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Sergey V. Ryazantsev
- Department
of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia
- Department
of Chemistry, University of Helsinki, P.O. Box 55, Helsinki FIN-00014, Finland
| | - Vladimir I. Feldman
- Department
of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia
| | - Leonid Khriachtchev
- Department
of Chemistry, University of Helsinki, P.O. Box 55, Helsinki FIN-00014, Finland
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24
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Kovács B, Kuş N, Tarczay G, Fausto R. Experimental Evidence of Long-Range Intramolecular Vibrational Energy Redistribution through Eight Covalent Bonds: NIR Irradiation Induced Conformational Transformation of E-Glutaconic Acid. J Phys Chem A 2017; 121:3392-3400. [PMID: 28423274 DOI: 10.1021/acs.jpca.7b00615] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Long-range intramolecular vibrational energy redistribution (IVR) driven conformational changes were investigated in a matrix-isolated open-chain, asymmetrical dicarboxylic acid, E-glutaconic acid. Although the analysis was challenging due to the presence of multiple backbone conformers and short lifetimes of the prepared higher energy cis conformers, it was shown that the selective excitation of the O-H stretching overtone of one of the carboxylic groups can induce the conformational change (trans to cis) of the other carboxylic group, located at the other end of the E-glutaconic acid molecule. This is a direct proof that the IVR process can act through eight covalent bonds in a flexible molecule before the excess energy completely dissipates into the matrix. The lifetime of the prepared higher energy conformers (averaged over the different backbones) was measured to be 12 s.
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Affiliation(s)
- Benjámin Kovács
- Institute of Chemistry, Eötvös University , PO Box 32, H-1518 Budapest 112, Hungary
| | - Nihal Kuş
- CQC, Department of Chemistry, University of Coimbra , 3004-535 Coimbra, Portugal.,Department of Physics, Anadolu University , TR-26470 Eskişehir, Turkey
| | - György Tarczay
- Institute of Chemistry, Eötvös University , PO Box 32, H-1518 Budapest 112, Hungary
| | - Rui Fausto
- CQC, Department of Chemistry, University of Coimbra , 3004-535 Coimbra, Portugal
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25
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Justino LLG, Reva I, Fausto R. Thermally and vibrationally induced conformational isomerizations, infrared spectra, and photochemistry of gallic acid in low-temperature matrices. J Chem Phys 2017; 145:014304. [PMID: 27394105 DOI: 10.1063/1.4954894] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Near-infrared (near-IR) narrowband selective vibrational excitation and annealing of gallic acid (3,4,5-trihydroxybenzoic acid) isolated in cryogenic matrices were used to induce interconversions between its most stable conformers. The isomerizations were probed by infrared spectroscopy. An extensive set of quantum chemical calculations, carried out at the DFT(B3LYP)/6-311++G(d,p) level of approximation, was used to undertake a detailed analysis of the ground state potential energy surface of the molecule. This investigation of the molecule conformational space allowed extracting mechanistic insights into the observed annealing- or near-IR-induced isomerization processes. The infrared spectra of the two most stable conformers of gallic acid in N2, Xe, and Ar matrices were fully assigned. Finally, the UV-induced photochemistry of the matrix isolated compound was investigated.
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Affiliation(s)
- Licínia L G Justino
- CQC, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
| | - Igor Reva
- CQC, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
| | - Rui Fausto
- CQC, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
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26
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Apóstolo R, Bazsó G, Bento R, Tarczay G, Fausto R. The first experimental observation of the higher-energy trans conformer of trifluoroacetic acid. J Mol Struct 2016. [DOI: 10.1016/j.molstruc.2016.06.077] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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27
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Cerveny S, Combarro-Palacios I, Swenson J. Evidence of Coupling between the Motions of Water and Peptides. J Phys Chem Lett 2016; 7:4093-4098. [PMID: 27683955 DOI: 10.1021/acs.jpclett.6b01864] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Studies of protein dynamics at low temperatures are generally performed on hydrated powders and not in biologically realistic solutions of water because of water crystallization. However, here we avoid the problem of crystallization by reducing the size of the biomolecules. We have studied oligomers of the amino acid l-lysine, fully dissolved in water, and our dielectric relaxation data show that the glass transition-related dynamics of the oligomers is determined by the water dynamics, in a way similar to that previously observed for solvated proteins. This implies that the crucial role of water for protein dynamics can be extended to other types of macromolecular systems, where water is also able to determine their conformational fluctuations. Using the energy landscape picture of macromolecules, the thermodynamic criterion for such solvent-slaved macromolecular motions may be that the macromolecules need the entropy contribution from the solvent to overcome the enthalpy barriers between different conformational substates.
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Affiliation(s)
- Silvina Cerveny
- Centro de Fisica de Materiales (CSIC, UPV/EHU)-Materials Physics Center (MPC) , Paseo Manuel de Lardizabal 5, 20018 San Sebastián, Spain
- Donostia International Physics Center, 20018 San Sebastián, Spain
| | - Izaskun Combarro-Palacios
- Centro de Fisica de Materiales (CSIC, UPV/EHU)-Materials Physics Center (MPC) , Paseo Manuel de Lardizabal 5, 20018 San Sebastián, Spain
| | - Jan Swenson
- Department of Applied Physics, Chalmers University of Technology , SE-412 96 Göteborg, Sweden
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28
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Mardyukov A, Quanz H, Schreiner PR. Conformer-specific hydrogen atom tunnelling in trifluoromethylhydroxycarbene. Nat Chem 2016; 9:71-76. [DOI: 10.1038/nchem.2609] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 09/09/2016] [Indexed: 11/09/2022]
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29
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Affiliation(s)
- Kedan He
- Department of Chemistry
and Center for Computational Quantum Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Wesley D. Allen
- Department of Chemistry
and Center for Computational Quantum Chemistry, University of Georgia, Athens, Georgia 30602, United States
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30
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Halasa A, Reva I, Lapinski L, Rostkowska H, Fausto R, Nowak MJ. Conformers of Kojic Acid and Their Near-IR-Induced Conversions: Long-Range Intramolecular Vibrational Energy Transfer. J Phys Chem A 2016; 120:2647-56. [DOI: 10.1021/acs.jpca.6b01275] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Anna Halasa
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland
| | - Igor Reva
- CQC, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
| | - Leszek Lapinski
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland
| | - Hanna Rostkowska
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland
| | - Rui Fausto
- CQC, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
| | - Maciej J. Nowak
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland
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31
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Lopes Jesus AJ, Reva I, Araujo-Andrade C, Fausto R. Conformational changes in matrix-isolated 6-methoxyindole: Effects of the thermal and infrared light excitations. J Chem Phys 2016; 144:124306. [PMID: 27036447 DOI: 10.1063/1.4944528] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Conformational changes induced thermally or upon infrared excitation of matrix-isolated 6-methoxyindole were investigated. Narrowband near-infrared excitation of the first overtone of the N-H stretching vibration of each one of the two identified conformers is found to induce a selective large-scale conversion of the pumped conformer into the other one. This easily controllable bidirectional process consists in the intramolecular reorientation of the methoxy group and allowed a full assignment of the infrared spectra of the two conformers. Matrices with different conformational compositions prepared by narrow-band irradiations were subsequently used to investigate the effects of both thermal and broadband infrared excitations on the conformational mixtures. Particular attention is given to the influence of the matrix medium (Ar vs. Xe) and conformational effects of exposition of the sample to the spectrometer light source during the measurements.
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Affiliation(s)
- A J Lopes Jesus
- CQC, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
| | - I Reva
- CQC, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
| | - C Araujo-Andrade
- CQC, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
| | - R Fausto
- CQC, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
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32
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Meisner J, Kästner J. Atom Tunneling in Chemistry. Angew Chem Int Ed Engl 2016; 55:5400-13. [DOI: 10.1002/anie.201511028] [Citation(s) in RCA: 140] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Revised: 01/08/2016] [Indexed: 01/01/2023]
Affiliation(s)
- Jan Meisner
- Institut für Theoretische Chemie Universität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany
| | - Johannes Kästner
- Institut für Theoretische Chemie Universität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany
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33
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Affiliation(s)
- Jan Meisner
- Institut für Theoretische Chemie Universität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Deutschland
| | - Johannes Kästner
- Institut für Theoretische Chemie Universität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Deutschland
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34
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Wagner JP, Reisenauer HP, Hirvonen V, Wu CH, Tyberg JL, Allen WD, Schreiner PR. Tunnelling in carbonic acid. Chem Commun (Camb) 2016; 52:7858-61. [DOI: 10.1039/c6cc01756h] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The cis,trans-conformer of carbonic acid (H2CO3), generated by near-infrared radiation, undergoes an unreported quantum mechanical tunnelling rotamerization with half-lives in cryogenic matrices of 4–20 h, depending on temperature and host material.
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Affiliation(s)
- J. Philipp Wagner
- Institute of Organic Chemistry
- Justus-Liebig University
- Heinrich-Buff-Ring 17
- D-35392 Giessen
- Germany
| | - Hans Peter Reisenauer
- Institute of Organic Chemistry
- Justus-Liebig University
- Heinrich-Buff-Ring 17
- D-35392 Giessen
- Germany
| | - Viivi Hirvonen
- Institute of Organic Chemistry
- Justus-Liebig University
- Heinrich-Buff-Ring 17
- D-35392 Giessen
- Germany
| | - Chia-Hua Wu
- Center for Computational Quantum Chemistry and Department of Chemistry
- University of Georgia
- Athens
- USA
| | - Joseph L. Tyberg
- Center for Computational Quantum Chemistry and Department of Chemistry
- University of Georgia
- Athens
- USA
| | - Wesley D. Allen
- Center for Computational Quantum Chemistry and Department of Chemistry
- University of Georgia
- Athens
- USA
| | - Peter R. Schreiner
- Institute of Organic Chemistry
- Justus-Liebig University
- Heinrich-Buff-Ring 17
- D-35392 Giessen
- Germany
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35
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Borba A, Gómez-Zavaglia A, Fausto R. Conformers, infrared spectrum, UV-induced photochemistry, and near-IR-induced generation of two rare conformers of matrix-isolated phenylglycine. J Chem Phys 2015; 141:154306. [PMID: 25338895 DOI: 10.1063/1.4897526] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The conformational space of α-phenylglycine (PG) have been investigated theoretically at both the DFT/B3LYP/6-311++G(d,p) and MP2/6-311++G(d,p) levels of approximation. Seventeen different minima were found on the investigated potential energy surfaces, which are characterized by different dominant intramolecular interactions: type I conformers are stabilized by hydrogen bonds of the type N-H···O=C, type II by a strong O-H···N hydrogen bond, type III by weak N-H···O-H hydrogen bonds, and type IV by a C=O···H-C contact. The calculations indicate also that entropic effects are relevant in determining the equilibrium populations of the conformers of PG in the gas phase, in particular in the case of conformers of type II, where the strong intramolecular O-H···N hydrogen bond considerably diminishes entropy by reducing the conformational mobility of the molecule. In consonance with the relative energies of the conformers and barriers for conformational interconversion, only 3 conformers of PG were observed for the compound isolated in cryogenic Ar, Xe, and N2 matrices: the conformational ground state (ICa), and forms ICc and IITa. All other significantly populated conformers existing in the gas phase prior to deposition convert either to conformer ICa or to conformer ICc during matrix deposition. The experimental observation of ICc had never been achieved hitherto. Narrowband near-IR irradiation of the first overtone of νOH vibrational mode of ICa and ICc in nitrogen matrices (at 6910 and 6930 cm(-1), respectively) led to selective generation of two additional conformers of high-energy, ITc and ITa, respectively, which were also observed experimentally for the first time. In addition, these experiments also provided the key information for the detailed vibrational characterization of the 3 conformers initially present in the matrices. On the other hand, UV irradiation (λ = 255 nm) of PG isolated in a xenon matrix revealed that PG undergoes facile photofragmentation through two photochemical pathways that are favored for different initial conformations of the reactant: (a) decarboxylation, leading to CO2 plus benzylamine (the dominant photofragmentation channel in PG cis-COOH conformers ICa and ICc) and (b) decarbonylation, with generation of CO plus benzonitrile, H2O and H2 (prevalent in the case of the trans-COOH conformer, IITa).
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Affiliation(s)
- Ana Borba
- Department of Chemistry, University of Coimbra, Coimbra P-3004-535, Portugal
| | | | - Rui Fausto
- Department of Chemistry, University of Coimbra, Coimbra P-3004-535, Portugal
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36
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Lopes Jesus AJ, Reva I, Araujo-Andrade C, Fausto R. Conformational Switching by Vibrational Excitation of a Remote NH Bond. J Am Chem Soc 2015; 137:14240-3. [DOI: 10.1021/jacs.5b08588] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- António Jorge Lopes Jesus
- CQC,
Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
- CQC,
Faculty of Pharmacy, University of Coimbra, 3004-295 Coimbra, Portugal
| | - Igor Reva
- CQC,
Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
| | - Cuauhtémoc Araujo-Andrade
- CQC,
Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
- Unidad Académica de Física de la Universidad Autónoma de Zacatecas, 98068 Zacatecas, Mexico
| | - Rui Fausto
- CQC,
Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
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37
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Barone V, Biczysko M, Bloino J, Cimino P, Penocchio E, Puzzarini C. CC/DFT Route toward Accurate Structures and Spectroscopic Features for Observed and Elusive Conformers of Flexible Molecules: Pyruvic Acid as a Case Study. J Chem Theory Comput 2015; 11:4342-63. [PMID: 26575928 PMCID: PMC5905675 DOI: 10.1021/acs.jctc.5b00580] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The structures and relative stabilities as well as the rotational and vibrational spectra of the three low-energy conformers of pyruvic acid (PA) have been characterized using a state-of-the-art quantum-mechanical approach designed for flexible molecules. By making use of the available experimental rotational constants for several isotopologues of the most stable PA conformer, Tc-PA, the semiexperimental equilibrium structure has been derived. The latter provides a reference for the pure theoretical determination of the equilibrium geometries for all conformers, thus confirming for these structures an accuracy of 0.001 Å and 0.1 deg for bond lengths and angles, respectively. Highly accurate relative energies of all conformers (Tc-, Tt-, and Ct-PA) and of the transition states connecting them are provided along with the thermodynamic properties at low and high temperatures, thus leading to conformational enthalpies accurate to 1 kJ mol(-1). Concerning microwave spectroscopy, rotational constants accurate to about 20 MHz are provided for the Tt- and Ct-PA conformers, together with the computed centrifugal-distortion constants and dipole moments required to simulate their rotational spectra. For Ct-PA, vibrational frequencies in the mid-infrared region accurate to 10 cm(-1) are reported along with theoretical estimates for the transitions in the near-infrared range, and the corresponding infrared spectrum including fundamental transitions, overtones, and combination bands has been simulated. In addition to the new data described above, theoretical results for the Tc- and Tt-PA conformers are compared with all available experimental data to further confirm the accuracy of the hybrid coupled-cluster/density functional theory (CC/DFT) protocol applied in the present study. Finally, we discuss in detail the accuracy of computational models fully based on double-hybrid DFT functionals (mainly at the B2PLYP/aug-cc-pVTZ level) that avoid the use of very expensive CC calculations.
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Affiliation(s)
- Vincenzo Barone
- Scuola Normale Superiore,
Piazza dei Cavalieri 7, I-56126 Pisa, Italy
| | - Malgorzata Biczysko
- Consiglio Nazionale delle
Ricerche, Istituto di Chimica dei Composti
OrganoMetallici (ICCOM-CNR), UOS di Pisa, Area
della Ricerca CNR, Via G. Moruzzi 1, I-56124 Pisa,
Italy
| | - Julien Bloino
- Consiglio Nazionale delle
Ricerche, Istituto di Chimica dei Composti
OrganoMetallici (ICCOM-CNR), UOS di Pisa, Area
della Ricerca CNR, Via G. Moruzzi 1, I-56124 Pisa,
Italy
| | - Paola Cimino
- Dipartimento di Scienze
Farmaceutiche, Università degli Studi di
Salerno, via Ponte don Melillo, I-84084 Fisciano
(SA), Italy
| | | | - Cristina Puzzarini
- Dipartimento di Chimica
“Giacomo Ciamician”,
Università di Bologna, Via Selmi 2, I-40126
Bologna, Italy
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38
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Najbauer EE, Bazsó G, Apóstolo R, Fausto R, Biczysko M, Barone V, Tarczay G. Identification of Serine Conformers by Matrix-Isolation IR Spectroscopy Aided by Near-Infrared Laser-Induced Conformational Change, 2D Correlation Analysis, and Quantum Mechanical Anharmonic Computations. J Phys Chem B 2015. [PMID: 26201050 DOI: 10.1021/acs.jpcb.5b05768] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The conformers of α-serine were investigated by matrix-isolation IR spectroscopy combined with NIR laser irradiation. This method, aided by 2D correlation analysis, enabled unambiguously grouping the spectral lines to individual conformers. On the basis of comparison of at least nine experimentally observed vibrational transitions of each conformer with empirically scaled (SQM) and anharmonic (GVPT2) computed IR spectra, six conformers were identified. In addition, the presence of at least one more conformer in Ar matrix was proved, and a short-lived conformer with a half-life of (3.7 ± 0.5) × 10(3) s in N2 matrix was generated by NIR irradiation. The analysis of the NIR laser-induced conversions revealed that the excitation of the stretching overtone of both the side chain and the carboxylic OH groups can effectively promote conformational changes, but remarkably different paths were observed for the two kinds of excitations.
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Affiliation(s)
- Eszter E Najbauer
- †Laboratory of Molecular Spectroscopy, Institute of Chemistry, Eötvös University, PO Box 32, H-1518, Budapest 112, Hungary
| | - Gábor Bazsó
- †Laboratory of Molecular Spectroscopy, Institute of Chemistry, Eötvös University, PO Box 32, H-1518, Budapest 112, Hungary
| | - Rui Apóstolo
- ‡Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
| | - Rui Fausto
- ‡Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
| | - Malgorzata Biczysko
- §Physics Department and International Centre for Quantum and Molecular Structure, Shanghai University, Shanghai, 200444 China
| | - Vincenzo Barone
- ∥Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa, Italy
| | - György Tarczay
- †Laboratory of Molecular Spectroscopy, Institute of Chemistry, Eötvös University, PO Box 32, H-1518, Budapest 112, Hungary
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39
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Cormanich RA, Bühl M, Rittner R. Understanding the conformational behaviour of Ac-Ala-NHMe in different media. A joint NMR and DFT study. Org Biomol Chem 2015. [PMID: 26219244 DOI: 10.1039/c5ob01296a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The conformational behaviour of Ac-Ala-NHMe was studied in the gas-phase and in solution by theoretical calculations (B3LYP-D3/aug-cc-pVDZ level) and experimental (1)H NMR. The conformational preferences of this compound were shown to result from a complex interplay between the strengths of possible intramolecular hydrogen bonds, steric interactions, hyperconjugation, entropy effects and the overall dipole moments. The Ac-Ala-N(Me)2 derivative was studied in addition, to design a system akin to Ac-Ala-NHMe, but with disrupted intramolecular hydrogen bonds involving the -NHMe group, mimicking the effect of polar protic solvents.
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Affiliation(s)
- Rodrigo A Cormanich
- Chemistry Institute, University of Campinas, Campinas, SP 13083-970, Brazil.
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40
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Schreiner PR, Wagner JP, Reisenauer HP, Gerbig D, Ley D, Sarka J, Császár AG, Vaughn A, Allen WD. Domino Tunneling. J Am Chem Soc 2015; 137:7828-34. [DOI: 10.1021/jacs.5b03322] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Peter R. Schreiner
- Institute
of Organic Chemistry, Justus-Liebig University, Heinrich-Buff-Ring 58, D-35392 Giessen, Germany
| | - J. Philipp Wagner
- Institute
of Organic Chemistry, Justus-Liebig University, Heinrich-Buff-Ring 58, D-35392 Giessen, Germany
| | - Hans Peter Reisenauer
- Institute
of Organic Chemistry, Justus-Liebig University, Heinrich-Buff-Ring 58, D-35392 Giessen, Germany
| | - Dennis Gerbig
- Institute
of Organic Chemistry, Justus-Liebig University, Heinrich-Buff-Ring 58, D-35392 Giessen, Germany
| | - David Ley
- Institute
of Organic Chemistry, Justus-Liebig University, Heinrich-Buff-Ring 58, D-35392 Giessen, Germany
| | - János Sarka
- Laboratory
of Molecular Structure and Dynamics, Institute of Chemistry, Eötvös University, PO Box 32, Budapest 112, Hungary, H-1518
- MTA-ELTE
Complex Chemical Systems Research Group, Eötvös University, Budapest, Pázmány Péter
Sétány 1/A, Hungary, H-1117
| | - Attila G. Császár
- Laboratory
of Molecular Structure and Dynamics, Institute of Chemistry, Eötvös University, PO Box 32, Budapest 112, Hungary, H-1518
- MTA-ELTE
Complex Chemical Systems Research Group, Eötvös University, Budapest, Pázmány Péter
Sétány 1/A, Hungary, H-1117
| | - Alexander Vaughn
- Center
for Computational Quantum Chemistry and Department of Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Wesley D. Allen
- Center
for Computational Quantum Chemistry and Department of Chemistry, University of Georgia, Athens, Georgia 30602, United States
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41
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Reva I, M Nunes C, Biczysko M, Fausto R. Conformational switching in pyruvic acid isolated in Ar and N₂ matrixes: spectroscopic analysis, anharmonic simulation, and tunneling. J Phys Chem A 2014; 119:2614-27. [PMID: 25332047 DOI: 10.1021/jp509578c] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Monomers of pyruvic acid (PA) isolated in cryogenic argon and nitrogen matrixes were characterized by mid- and near-infrared spectroscopy. Interpretation of the experiments was aided by fully anharmonic calculations of the fundamental modes, overtones, and combinations up to two quanta, including their infrared intensities. The initially dominating PA conformer (Tc) has a cis CCOH arrangement and is stabilized by a strong intramolecular H-bond. Selective near-infrared excitation of Tc at the first OH overtone (6630 cm(-1) in Ar, 6643 cm(-1) in N2) induced a large scale conformational conversion to the higher-energy conformer (Tt) with trans CCOH arrangement. Tt was then converted back to Tc by selective NIR irradiation at the first Tt OH overtone (6940 cm(-1) in Ar, 6894 cm(-1) in N2). In N2 matrix, the Tt form was stabilized due to interaction between the OH group and the matrix molecules. This stabilization manifested itself in the absence of Tt → Tc relaxation and in a considerable change of the vibrational Tt signature upon going from argon to nitrogen matrix. In argon, the Tt form spontaneously decayed back to Tc in the dark (characteristic lifetime +16 h). In the presence of broad-band near-infrared light, the Tt → Tc relaxation speed considerably increased. The decay mechanisms are discussed.
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Affiliation(s)
- Igor Reva
- †CQC, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
| | - Cláudio M Nunes
- †CQC, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
| | - Malgorzata Biczysko
- ‡Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa, Italy.,§Consiglio Nazionale delle Ricerche, Istituto di Chimica dei Composti OrganoMetallici (ICCOM-CNR), UOS di Pisa, Area della Ricerca CNR, Via G. Moruzzi 1, I-56124 Pisa, Italy
| | - Rui Fausto
- †CQC, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
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42
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Kócs L, Najbauer EE, Bazsó G, Magyarfalvi G, Tarczay G. Near-Infrared Laser-Induced Structural Changes of Glycine·Water Complexes in an Ar Matrix. J Phys Chem A 2014; 119:2429-37. [DOI: 10.1021/jp508493c] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Lenke Kócs
- 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 Bazsó
- 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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43
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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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44
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Halasa A, Lapinski L, Reva I, Rostkowska H, Fausto R, Nowak MJ. Near-infrared laser-induced generation of three rare conformers of glycolic acid. J Phys Chem A 2014; 118:5626-35. [PMID: 25002253 DOI: 10.1021/jp5051589] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Structural transformations were induced in conformers of glycolic acid by selective excitation with monochromatic tunable near-infrared laser light. For the compound isolated in Ar matrixes, near-IR excitation led to generation of two higher-energy conformers (GAC; AAT) differing from the most stable SSC form by 180° rotation around the C-C bond. A detailed investigation of this transformation revealed that one conformer (GAC) is produced directly from the near-IR-excited most stable conformer. The other higher-energy conformer (AAT) was effectively generated only upon excitation of the primary photoproduct (GAC) with another near-IR photon. Once these higher-energy conformers of glycolic acid were generated in an Ar matrix, they could be subsequently transformed into one another upon selective near-IR excitations. Interestingly, no repopulation of the initial most stable SSC conformer occurred upon near-IR excitation of the higher-energy forms of the compound isolated in solid Ar. A dramatically different picture of near-IR-induced conformational transformations was observed for glycolic acid isolated in N2 matrixes. In this case, upon near-IR excitation, the most stable SSC form converted solely into a new conformer (SST), where the acid OH group is rotated by 180°. This conformational transformation was found to be photoreversible. Moreover, SST conformer, photoproduced in the N2 matrix, spontaneously converted to the most stable SSC form of glycolic acid, when the matrix was kept at cryogenic temperature and in the dark.
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Affiliation(s)
- Anna Halasa
- Institute of Physics, Polish Academy of Sciences , Al. Lotnikow 32/46, 02-668 Warsaw, Poland
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45
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Araujo-Andrade C, Reva I, Fausto R. Tetrazole acetic acid: Tautomers, conformers, and isomerization. J Chem Phys 2014; 140:064306. [DOI: 10.1063/1.4864119] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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46
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Najbauer EE, Bazsó G, Góbi S, Magyarfalvi G, Tarczay G. Exploring the Conformational Space of Cysteine by Matrix Isolation Spectroscopy Combined with Near-Infrared Laser Induced Conformational Change. J Phys Chem B 2014; 118:2093-103. [DOI: 10.1021/jp412550q] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Eszter E. Najbauer
- Laboratory of Molecular Spectroscopy,
Institute of Chemistry, Eötvös University, P.O. Box 32 H-1518, Budapest 112, Hungary
| | - Gábor Bazsó
- Laboratory of Molecular Spectroscopy,
Institute of Chemistry, Eötvös University, P.O. Box 32 H-1518, Budapest 112, Hungary
| | - Sándor Góbi
- 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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47
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Rode JE, Dobrowolski JC, Sadlej J. Prediction of l-Methionine VCD Spectra in the Gas Phase and Water Solution. J Phys Chem B 2013; 117:14202-14. [DOI: 10.1021/jp405462a] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Joanna E. Rode
- Industrial Chemistry Research Institute, 8 Rydygiera Street, 01-793 Warsaw, Poland
| | - Jan Cz. Dobrowolski
- Industrial Chemistry Research Institute, 8 Rydygiera Street, 01-793 Warsaw, Poland
- National Medicines Institute, 30/34 Chełmska Street, 00-725 Warsaw, Poland
| | - Joanna Sadlej
- National Medicines Institute, 30/34 Chełmska Street, 00-725 Warsaw, Poland
- Faculty
of Chemistry, Warsaw University, 1 Pasteura Street, 02-093 Warsaw, Poland
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Walker M, Harvey AJA, Sen A, Dessent CEH. Performance of M06, M06-2X, and M06-HF density functionals for conformationally flexible anionic clusters: M06 functionals perform better than B3LYP for a model system with dispersion and ionic hydrogen-bonding interactions. J Phys Chem A 2013; 117:12590-600. [PMID: 24147965 DOI: 10.1021/jp408166m] [Citation(s) in RCA: 442] [Impact Index Per Article: 40.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We present a comparative assessment of the performance of the M06 suite of density functionals (M06, M06-2X, and M06-HF) against an MP2 benchmark for calculating the relative energies and geometric structures of the Cl(-)·arginine and Br(-)·arginine halide ion-amino acid clusters. Additional results are presented for the popular B3LYP density functional. The Cl(-)·arginine and Br(-)·arginine complexes are important prototypes for the phenomenon of anion-induced zwitterion formation. Results are presented for the canonical (noncharge separated) and zwitterionic (charge separated) tautomers of the clusters, as well as the numerous conformational isomers of the clusters. We find that all of the M06 functions perform well in terms of predicting the general trends in the conformer relative energies and identifying the global minimum conformer. This is in contrast to the B3LYP functional, which performed significantly less well for the canonical tautomers of the clusters where dispersion interactions contribute more significantly to the conformer energetics. We find that the M06 functional gave the lowest mean unsigned error for the relative energies of the canonical conformers (2.10 and 2.36 kJ/mol for Br(-)·arginine and Cl(-)·arginine), while M06-2X gave the lowest mean unsigned error for the zwitterionic conformers (0.85 and 1.23 kJ/mol for Br(-)·arginine and Cl(-)·arginine), thus providing insight into the types of physical systems where each of these functionals should perform best.
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Affiliation(s)
- Martin Walker
- Department of Chemistry, University of York , Heslington, York YO10 5DD, U.K
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Kuş N, Bayarı SH, Fausto R. Methylparaben Isolated in Solid Argon: Structural Characterization and UV-Induced Conversion into Methylparaben Radical and Isomeric Ketenes. J Phys Chem B 2013; 117:13543-55. [DOI: 10.1021/jp408366x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Nihal Kuş
- Department
of Chemistry, University of Coimbra, P-3004-535 Coimbra, Portugal
- Department
of Physics, Anadolu University, 26470 Eskişehir, Turkey
| | - Sevgi H. Bayarı
- Department
of Physics, Hacettepe University, 06800 Ankara, Turkey
| | - Rui Fausto
- Department
of Chemistry, University of Coimbra, P-3004-535 Coimbra, Portugal
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50
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Foldamers of β-peptides: conformational preference of peptides formed by rigid building blocks. The first MI-IR spectra of a triamide nanosystem. Amino Acids 2013; 45:957-73. [DOI: 10.1007/s00726-013-1552-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Accepted: 06/28/2013] [Indexed: 10/26/2022]
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