1
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Tanaka K, Harada K, Watanabe Y, Endo Y. Fourier transform microwave spectroscopy of the 13C- and 18O-substituted tropolone. Proton tunneling effect for the isotopic species with the asymmetric potential wells. J Chem Phys 2024; 160:214311. [PMID: 38836453 DOI: 10.1063/5.0204891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Accepted: 05/17/2024] [Indexed: 06/06/2024] Open
Abstract
Fourier-transform microwave spectroscopy has been applied for the 13C/18O-substituted tropolone to observe tunneling-rotation transitions as well as pure rotational transitions. The tunneling-rotation transitions were observed between the 13C-4 and -6 forms as well as between 13C-3 and -7, between 13C-1 and -2, and between 18O-8 and -9 (we denote these tunneling pairs as 13C-46, etc., below) although they have an asymmetric tunneling potential due to the difference in the zero point energy (ZPE). From the observed tunneling splittings ΔEij (0.9800-1.6824 cm-1), the differences in ZPE Δij for the 13C-46, -37, -12, and 18O-89 species are derived to be -0.1104, 0.5652, -1.3682, and 1.3897 cm-1 to agree well with the DFT calculation. The state mixing ratio of the tunneling states decreases drastically from (44%:56%) to (8.7%:91.3%) for 13C-46 and 18O-89 with an increase in the asymmetry Δij of the tunneling potential function. The observed tunneling-rotation interaction constants Fij decrease from 16.001 to 9.224 cm-1 as the differences in ZPE Δij increase, while the diagonal tunneling-rotation interaction constants Fu increase from 1.767 to 13.70 cm-1, explained well by the mixing ratio of the tunneling states.
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Affiliation(s)
- Keiichi Tanaka
- Department of Chemistry, Faculty of Science, Kyushu University, Motooka, Nishiku, Fukuoka 819-0395, Japan
- International Research Center for Space and Planetary Environmental Science, Kyushu University, Motooka, Nishiku, Fukuoka 819-0395, Japan
| | - Kensuke Harada
- Department of Chemistry, Faculty of Science, Kyushu University, Motooka, Nishiku, Fukuoka 819-0395, Japan
- International Research Center for Space and Planetary Environmental Science, Kyushu University, Motooka, Nishiku, Fukuoka 819-0395, Japan
| | - Yoshihiro Watanabe
- Department of Chemistry, Faculty of Science, Kyushu University, Motooka, Nishiku, Fukuoka 819-0395, Japan
| | - Yasuki Endo
- Department of Applied Chemistry, National Yang Ming Chiao Tung University, 1001 Ta-Hsueh Rd., Hsinchu 30093, Taiwan
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2
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Videla PE, Foguel L, Vaccaro PH, Batista VS. Proton-Tunneling Dynamics along Low-Barrier Hydrogen Bonds: A Full-Dimensional Instanton Study of 6-Hydroxy-2-formylfulvene. J Phys Chem Lett 2023:6368-6375. [PMID: 37418693 DOI: 10.1021/acs.jpclett.3c01337] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/09/2023]
Abstract
Understanding the dynamics of proton transfer along low-barrier hydrogen bonds remains an outstanding challenge of great fundamental and practical interest, reflecting the central role of quantum effects in reactions of chemical and biological importance. Here, we combine ab initio calculations with the semiclassical ring-polymer instanton method to investigate tunneling processes on the ground electronic state of 6-hydroxy-2-formylfulvene (HFF), a prototypical neutral molecule supporting low-barrier hydrogen-bonding. The results emerging from a full-dimensional ab initio instanton analysis reveal that the tunneling path does not pass through the instantaneous transition-state geometry. Instead, the tunneling process involves a multidimensional reaction coordinate with concerted reorganization of the heavy-atom skeletal framework to substantially reduce the donor-acceptor distance and drive the ensuing intramolecular proton-transfer event. The predicted tunneling-induced splittings for HFF isotopologues are in good agreement with experimental findings, leading to percentage deviations of only 20-40%. Our full-dimensional results allow us to characterize vibrational contributions along the tunneling path, highlighting the intrinsically multidimensional nature of the attendant hydron-migration dynamics.
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Affiliation(s)
- Pablo E Videla
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - Lidor Foguel
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - Patrick H Vaccaro
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - Victor S Batista
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
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3
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Bowman JM, Qu C, Conte R, Nandi A, Houston PL, Yu Q. Δ-Machine Learned Potential Energy Surfaces and Force Fields. J Chem Theory Comput 2023; 19:1-17. [PMID: 36527383 DOI: 10.1021/acs.jctc.2c01034] [Citation(s) in RCA: 25] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
There has been great progress in developing machine-learned potential energy surfaces (PESs) for molecules and clusters with more than 10 atoms. Unfortunately, this number of atoms generally limits the level of electronic structure theory to less than the "gold standard" CCSD(T) level. Indeed, for the well-known MD17 dataset for molecules with 9-20 atoms, all of the energies and forces were obtained with DFT calculations (PBE). This Perspective is focused on a Δ-machine learning method that we recently proposed and applied to bring DFT-based PESs to close to CCSD(T) accuracy. This is demonstrated for hydronium, N-methylacetamide, acetyl acetone, and ethanol. For 15-atom tropolone, it appears that special approaches (e.g., molecular tailoring, local CCSD(T)) are needed to obtain the CCSD(T) energies. A new aspect of this approach is the extension of Δ-machine learning to force fields. The approach is based on many-body corrections to polarizable force field potentials. This is examined in detail using the TTM2.1 water potential. The corrections make use of our recent CCSD(T) datasets for 2-b, 3-b, and 4-b interactions for water. These datasets were used to develop a new fully ab initio potential for water, termed q-AQUA.
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Affiliation(s)
- Joel M Bowman
- Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322, United States
| | - Chen Qu
- Independent Researcher, Toronto, Canada 66777
| | - Riccardo Conte
- Dipartimento di Chimica, Università Degli Studi di Milano, via Golgi 19, 20133 Milano, Italy
| | - Apurba Nandi
- Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322, United States
| | - Paul L Houston
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States.,Department of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Qi Yu
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
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4
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Houston P, Conte R, Qu C, Bowman JM. Permutationally invariant polynomial potential energy surfaces for tropolone and H and D atom tunneling dynamics. J Chem Phys 2020; 153:024107. [DOI: 10.1063/5.0011973] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Affiliation(s)
- Paul Houston
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, USA and Department of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | - Riccardo Conte
- Dipartimento di Chimica, Università Degli Studi di Milano, via Golgi 19, 20133 Milano, Italy
| | - Chen Qu
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, USA
| | - Joel M. Bowman
- Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322, USA
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5
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Lin C, Durant E, Persson M, Rossi M, Kumagai T. Real-Space Observation of Quantum Tunneling by a Carbon Atom: Flipping Reaction of Formaldehyde on Cu(110). J Phys Chem Lett 2019; 10:645-649. [PMID: 30676024 PMCID: PMC6728093 DOI: 10.1021/acs.jpclett.8b03806] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 01/24/2019] [Indexed: 06/09/2023]
Abstract
We present a direct observation of carbon-atom tunneling in the flipping reaction of formaldehyde between its two mirror-reflected states on a Cu(110) surface using low-temperature scanning tunneling microscopy (STM). The flipping reaction was monitored in real time, and the reaction rate was found to be temperature independent below 10 K. This indicates that this reaction is governed by quantum mechanical tunneling, albeit involving a substantial motion of the carbon atom (∼1 Å). In addition, deuteration of the formaldehyde molecule resulted in a significant kinetic isotope effect ( RCH2O/ RCD2O ≈ 10). The adsorption structure, reaction pathway, and tunneling probability were examined by density functional theory calculations, which corroborate the experimental observations.
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Affiliation(s)
- Chenfang Lin
- Department
of Physical Chemistry, Fritz-Haber Institute
of the Max-Planck Society, Faradayweg 4-6, 14195 Berlin, Germany
| | - Emile Durant
- Surface
Science Research Centre and Department of Chemistry, University of Liverpool, Liverpool L69 3BX, U.K.
| | - Mats Persson
- Surface
Science Research Centre and Department of Chemistry, University of Liverpool, Liverpool L69 3BX, U.K.
| | - Mariana Rossi
- Theory
Department, Fritz-Haber Institute of the
Max-Planck Society, Faradayweg
4-6, 14195 Berlin, Germany
| | - Takashi Kumagai
- Department
of Physical Chemistry, Fritz-Haber Institute
of the Max-Planck Society, Faradayweg 4-6, 14195 Berlin, Germany
- JST-PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
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6
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Theoretical Modeling of Vibrational Spectra and Proton Tunneling in Hydrogen-Bonded Systems. ADVANCES IN CHEMICAL PHYSICS 2016. [DOI: 10.1002/9781119165156.ch6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
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7
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Mengesha ET, Sepioł J, Borowicz P, Waluk J. Vibrations of porphycene in the S0 and S1 electronic states: Single vibronic level dispersed fluorescence study in a supersonic jet. J Chem Phys 2013; 138:174201. [DOI: 10.1063/1.4802769] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
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8
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Zborowski KK, Jezierski G, Kim Y, Proniewicz LM. Tautomerism of Neutral α-Tropolone and its Protonated and Deprotonated Forms. Z PHYS CHEM 2013. [DOI: 10.1524/zpch.2013.0351] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Abstract
Possible structures of α-tropolone (2-hydroxy-2,4,6-cycloheptatrien-1-one) tautomers: four neutral, thirteen protonated, and four deprotonated, are studied at the B3LYP/6-311++G∗∗ computational level. The energies and the free energies calculated for the studied tautomers show that for each of the three forms, among all the possible tautomers in the tautomeric mixture, only one structure is expected: a keto-enol structure with an intramolecular hydrogen bond (neutral α-tropolone molecule), the structure with two deprotonated exocyclic oxygen atoms (tropolonate, deprotonated tropolone), and the structure with two hydroxyl group forming an intramolecular hydrogen bond (protonated tropolone). The relative energies of the studied tautomers are rationalized based on the results from the atomic energy integration performed within the frame of the Quantum Theory of Atoms in Molecules.
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Affiliation(s)
| | | | - Younkoyoo Kim
- Hankuk University of Foreign Studies, Department of Chemistry, Republik Korea
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9
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Murdock D, Burns LA, Vaccaro PH. Vibrational specificity of proton-transfer dynamics in ground-state tropolone. Phys Chem Chem Phys 2010; 12:8285-99. [DOI: 10.1039/c003140b] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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10
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Lin W, Pringle WC, Novick SE, Blake TA. Microwave spectrum of the argon-tropolone van der Waals complex. J Phys Chem A 2009; 113:13076-80. [PMID: 19441806 DOI: 10.1021/jp901086a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The rotational spectrum of the argon-tropolone van der Waals complex in the ground vibrational state has been measured in the frequency range of 6-17 GHz using a pulsed-jet, Balle-Flygare-type Fourier transform microwave spectrometer. Eighty-six transitions for the complex (Ar-(12)C(7)H(6)(16)O(2)) were observed, assigned, and fit using a Watson A-reduction Hamiltonian giving the rotational and centrifugal distortion constants A = 1080.4365(3) MHz, B = 883.4943(3) MHz, C = 749.0571(2) MHz, Delta(J) = 2.591(2) kHz, Delta(JK) = -3.32(1) kHz, Delta(K) = 5.232(9) kHz, delta(J) = 0.944(1) kHz, and delta(K) = -0.028(8) kHz. The tunneling motion of the hydroxyl proton in the tropolone moiety is quenched in the ground electronic state by complexation with argon. The coordinates of the argon atom in the monomer's principal axis system are a = 0.43 A, b = 0.23 A, and c = 3.48 A.
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Affiliation(s)
- Wei Lin
- Department of Natural Sciences and Mathematics, University of Saint Mary, Leavenworth, Kansas 66048, USA
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11
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Redington RL, Redington TE, Sams RL. Infrared Absorption Spectra in the Hydroxyl Stretching Regions of Gaseous Tropolone OHO Isotopomers. ACTA ACUST UNITED AC 2009. [DOI: 10.1524/zpch.2008.5383] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Abstract
Fourier transform infrared (FTIR) absorption spectra in the 2000 to 3500 cm–1 range are reported for the gaseous 16
O,
16
O- and 18
O,
18
O-isotopomers of tropolone[OH(OD)] at 25 oC. The spectral doublet component separations are near 20 and 19 cm–1 for 16
O,
16
O- and 18
O,
18
O-Tp(OH), respectively, and near 7 and 6.5 cm–1 for 16
O,
16
O- and 18
O,
18
O-Tp(OD). The spectra suggest the tautomerization tunneling mechanisms in these states are complex multidimensional processes including the participation of IVR. In general, the OHO isotope effects demonstrate a mixing of O atom displacement coordinates into the intramolecular dynamics for most of the vibrational states observed in the fundamental CH/OH(OD) stretching regions.
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12
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Redington RL, Redington TE, Sams RL. Tunneling Splittings for “O···O Stretching” and Other Vibrations of Tropolone Isotopomers Observed in the Infrared Spectrum Below 800 cm-1. J Phys Chem A 2008; 112:1480-92. [DOI: 10.1021/jp0757255] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Richard L. Redington
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409
| | - Theresa E. Redington
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409
| | - Robert L. Sams
- Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352
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13
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Redington RL, Redington TE, Sams RL. Quantum Tunneling in the Midrange Vibrational Fundamentals of Tropolone. J Phys Chem A 2006; 110:9633-42. [PMID: 16884197 DOI: 10.1021/jp062068s] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The Fourier transform infrared spectrum of tropolone(OH) vapor in the 1175-1700 cm(-1) region is reported at 0.0025 and 0.10 cm(-1) spectral resolutions. The 12 vibrational fundamentals in this region of rapidly rising vibrational state density are dominated by mixtures of the CC, CO, CCH, and COH internal coordinates. Estimates based on the measurement of sharp Q branch peaks are reported for 11 of the spectral doublet component separations DS(v) = |Delta(v) +/- Delta(0)|. Delta(0) = 0.974 cm(-1) is the known zero-point splitting, and three a(1) modes show tunneling splittings Delta(v) approximately Delta(0), four b(2) modes show splittings Delta(v) approximately 0.90Delta(0), and the remaining four modes show splittings Delta(v) falling 5-14% from Delta(0.) Significantly, the splitting for the nominal COH bending mode nu(8) (a(1)) is small, that is, 10% from Delta(0). Many of the vibrational excited states demonstrate strong anharmonic behavior, but there are only mild perturbations on the tautomerization mechanism driving Delta(0). The data suggest, especially for the higher frequency a(1) fundamentals, the onset of selective intramolecular vibrational energy redistribution processes that are fast on the time scale of the tautomerization process. These appear to delocalize and smooth out the topographical modifications of the zero-point potential energy surface that are anticipated to follow absorption of the nu(v) photon. Further, the spectra show the propensity for the Delta(v) splittings of b(2) and other complex vibrations to be damped relative to Delta(0).
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Affiliation(s)
- Richard L Redington
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409, USA
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14
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Keske JC, Lin W, Pringle WC, Novick SE, Blake TA, Plusquellic DF. High-resolution studies of tropolone in the S0 and S1 electronic states: Isotope driven dynamics in the zero-point energy levels. J Chem Phys 2006; 124:74309. [PMID: 16497038 DOI: 10.1063/1.2165652] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Rotationally resolved microwave (MW) and ultraviolet (UV) spectra of jet-cooled tropolone have been obtained in S(0) and S(1) electronic states using Fourier-transform microwave and UV-laser/molecular-beam spectrometers. In the ground electronic state, the MW spectra of all heavy-atom isotopomers including one (18)O and four (13)C isotopomers were observed in natural abundance. The OD isotopomer was obtained from isotopically enriched samples. The two lowest tunneling states of each isotopomer except (18)O have been assigned. The observed inversion splitting for the OD isotopomer is 1523.227(5) MHz. For the asymmetric (13)C structures, the magnitudes of tunneling-rotation interactions are found to diminish with decreasing distance between the heavy atom and the tunneling proton. In the limit of closest approach, the 0(+) state of (18)O was well fitted to an asymmetric rotor Hamiltonian, reflecting significant changes in the tautomerization dynamics. Comparisons of the substituted atom coordinates with theoretical predictions at the MP2/aug-cc-pVTZ level of theory suggest the localized 0(+) and 0(-) wave functions of the heavier isotopes favor the C-OH and C=O forms of tropolone, respectively. The only exception occurs for the (13)C-OH and (13)C[Double Bond]O structures which correlate to the 0(-) and 0(+) states, respectively. These preferences reflect kinetic isotope effects as quantitatively verified by the calculated zero-point energy differences between members of the asymmetric atom pairs. From rotationally resolved data of the 0(+) <--0(+) and 0(-) <--0(-) bands in S(1), line-shape fits have yielded Lorentzian linewidths that differ by 12.2(16) MHz over the 19.88(4) cm(-1) interval in S(1). The fluorescence decay rates together with previously reported quantum yield data give nonradiative decay rates of 7.7(5) x 10(8) and 8.5(5) x 10(8) s(-1) for the 0(+) and 0(-) levels of the S(1) state of tropolone.
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Affiliation(s)
- John C Keske
- Optical Technology Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8441, USA
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15
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Redington RL. Isoelectronic Homologues and Isomers: Tropolone, 5-Azatropolone, 1-H-Azepine-4,5-dione, Saddle Points, and Ions. J Phys Chem A 2005; 110:1600-7. [PMID: 16435822 DOI: 10.1021/jp053928s] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Computational studies of 12 64-electron homologues and isomers of tropolone in the S(0) electronic ground state are reported. Three minimum-energy structures, tropolone (Tp), 5-azatropolone (5Azt), and 5-H-5-azatropolonium (5AztH(+)), have an internal H-bond and planar C(s)) geometry, and three, tropolonate (TpO(-)), 5-azatropolonate (5AzO(-)), and 1-H-azepine-4,5-dione (45Di), lack the H-bond and have twisted C(2) geometry. All 6 substances have an equal double-minimum potential energy surface and a saddle point with planar C(2)(v) geometry. The energy for the gas-phase isomerization reaction 45Di --> 5Azt is near +4 kJ mol(-1) at the MP4(SDQ)/6-311++G(df,pd)//MP2/6-311++G(df,pd) (energy//geometry) theoretical level and around -20 kJ mol(-1) at lower theoretical levels. The dipole moments computed for 45Di and 5Azt are 9.6 and 2.1 D, respectively, and this large difference contributes to MO-computed free energies of solvation that strongly favor--as experimentally observed--45Di over 5Azt in chloroform solvent. The MO-computed energy for the gas-phase protonation reaction 45Di + H(+) --> 5AztH(+) is -956.4 kJ mol(-1), leading to 926.8 kJ mol(-1) as the estimated proton affinity for 45Di at 298 K and 1 atm. The intramolecular dynamical properties predicted for 5Azt and 5AztH(+) parallel those observed for tropolone. They are therefore expected to exhibit spectral tunneling doublets. Once they are synthesized, they should contribute importantly to the understanding of multidimensional intramolecular H transfer and dynamical coupling processes.
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Affiliation(s)
- Richard L Redington
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409, USA
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