Coupling of internal rotation of methyl group with proton transfer in the S1 state of 5-methyltropolone

Nishi, Koji; Sekiya, Hiroshi; Kawakami, Hiroko; Mori, Akira; Nishimura, Yukio

doi:10.1063/1.476731

Cited by 35 publications

(18 citation statements)

References 17 publications

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“…From the theoretical point of view proton transfer in the ground electronic state is more easily tractable. Extensive experimental and theoretical studies have been reported for multidimensional proton tunneling in tropolone [3][4][5][6][7][8][9][10][11][12][13]. Vener et al [10] studied theoretically multidimensional proton tunneling in tropolone by using adiabatic separation of variables.…”

Section: Introductionmentioning

confidence: 99%

“…Other systems for which tunnelling have been studied include malonaldehyde [14][15][16][17], formic acid [18], hydrogen-oxalate anion [16], substituted tropolone [19,20] and 5-methyl-9-hydroxyphenalenone (OH and OD) [21], methanol tetramer [22] and hydrogen carbonate dimer ion [23]. Recently a mixed quantum-classical approach has been used to study dynamics of hydrogen-bonded systems [24,25].…”

Section: Introductionmentioning

confidence: 99%

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Theoretical Study of Multidimensional Proton Tunnelling in Benzoic Acid Dimer

Wójcik

Szczeponek

Boczar

2003

IJMS

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Theoretical Study of Multidimensional Proton Tunnelling in Benzoic Acid Dimer

Wójcik

Szczeponek

Boczar

2003

IJMS

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“…In the lowest energy configuration the two OH bonds point in opposing directions. Resolved spectral tunneling structures similar to those of the parent TRN(OH) and TRN(OD) molecules are observed for the aforementioned molecules, as well as others: 5-methyl-tropolone [53,54], isopropyltropolones [55], and 5-phenyl-tropolone [56][57]. The effects of coupling the OH_O coordinates to the methyl internal rotation, or of coupling them to the low frequency phenyl torsional motions, are of interest.…”

Section: Discussionmentioning

confidence: 90%

“…The topography of its PES has saddle-point (SP) energy barriers just low enough, and tautomer-to-tautomer heavy atom excursions that are just short enough, to produce numerous resolvable vibrational state-specific coherent tunneling splittings. They are also observed in the 2 H [40,41] and 18 O [39, 42, 43] isotopomers of gaseous TRN, and in simple chemical derivatives [44][45][46][47][48][49][50][51][52][53][54][55][56][57]. The numerous van der Waals complexes of tropolone are not discussed in this chapter.…”

Section: Introductionmentioning

confidence: 99%

Coherent Proton Tunneling in Hydrogen Bonds of Isolated Molecules: Malonaldehyde and Tropolone

Redington

2006

Hydrogen‐Transfer Reactions

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A series of articles reporting temperature dependent H and D isotope effects on the rates of certain enzymatic H transfer reactions show there is quantum tunneling by the H in these systems [1][2][3][4][5][6][7]. Theoretical considerations [4,6,7] infer vibrations within the enzyme-substrate complex, especially within the enzyme protein, develop transient geometrical configurations fomenting the tunneling process. Details of the promoting vibrations are still speculative, but it seems clear they work through transient reshaping of the potential energy surface (PES) barrier region, its width, energy maximum, overall contour, to provide "gated" impetus to H tunneling and to product escape.Molecules hosting coherent H tunneling activity in the presence of complex vibrational structure are of immediate interest in the above context. They provide sharp data points probing specific vibrational couplings along the large amplitude tunneling coordinate, and they probe portions of the PES topography in detail. Studies on isotopomers and close chemical congeners provide clusters of data points reflecting systematic changes of the dynamical behavior. In this chapter research on the coherent tunneling properties of malonaldehyde, tropolone, and tropolone derivatives is surveyed. These are among the few currently known 10-15 atom molecules showing clear-cut spectral doublet structures signifying coherent tunneling properties. Interestingly, the equal double-minimum global PESs for these molecules, notably for S 0 tropolone, are also poised for demonstrations of tunneling activity by the heavy atoms. The presence of H tunneling in some enzymatic systems is newly recognized; tunneling processes by heavy atoms such as C, N, and O may also prove consequential. Zuev et al. [8] recently published low temperature rate data and theoretical-computational results showing the tunneling of C atom from a single quantum state during the ring expansion isomerization of 1-methycyclobutylfluorocarbene.

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“…Tropolone with its intramolecular hydrogen bond is a model substance for studying tunneling process in the ground as well as in the excited electronic state [50][51][52][53][54][55][56][57][58][59]. The geometry of tropolone is presented in Figure 4.…”

Section: Introductionmentioning

confidence: 99%

Theoretical Studies of Dynamic Interactions in Excited States of Hydrogen-Bonded Systems

Wójcik

Boczar

Boda

2012

Journal of Atomic, Molecular, and Optical Physics

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Theoretical model for vibrational interactions in the hydrogen-bonded benzoic acid dimer is presented. The model takes into account anharmonic-type couplings between the high-frequency O-H and the low-frequency O· · · O stretching vibrations in two hydrogen bonds, resonance interactions between two hydrogen bonds in the dimer, and Fermi resonance between the O-H stretching fundamental and the first overtone of the O-H in-plane bending vibrations. The model is used for theoretical simulation of the O-H stretching IR absorption bands of benzoic acid dimers in the gas phase in the first excited singlet state. Ab initio CIS and CIS(D)/CIS/6-311++G(d,p) calculations have been carried out in theÃ state of tropolone. The grids of potential energy surfaces along the coordinates of the tunneling vibration and the low-frequency coupled vibration have been calculated. Two-dimensional model potentials have been fitted to the calculated potential energy surfaces. The tunneling splittings for vibrationally excited states have been calculated and compared with the available experimental data. The model potential energy surfaces give good estimation of the tunneling splittings in the vibrationally ground and excited states of tropolone, and explain monotonic decrease in tunneling splittings with the excitation of low-frequency out-of-plane modes and increase of the tunneling splittings with the excitation of low-frequency planar modes.

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Coupling of internal rotation of methyl group with proton transfer in the S1 state of 5-methyltropolone

Cited by 35 publications

References 17 publications

Theoretical Study of Multidimensional Proton Tunnelling in Benzoic Acid Dimer

Theoretical Study of Multidimensional Proton Tunnelling in Benzoic Acid Dimer

Coherent Proton Tunneling in Hydrogen Bonds of Isolated Molecules: Malonaldehyde and Tropolone

Theoretical Studies of Dynamic Interactions in Excited States of Hydrogen-Bonded Systems

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