Investigation of intramolecular hydrogen bonds in <i>ortho</i>-hydroxytropolone

Tsuji, Takeshi; Hamabe, Hidenori; Hayashi, Yoshiyuki; Sekiya, Hiroshi; Mori, Akira; Nishimura, Yukio

doi:10.1063/1.478142

Cited by 9 publications

(4 citation statements)

References 31 publications

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“…Tropolone (Shimanouchi & Sasada, 1973) and its 5-substituted derivatives (Kubo et al, 2001(Kubo et al, , 2006a form centrosymmetric O-HÁ Á ÁO hydrogen-bonded dimers, while 3-hydroxytropolone exhibits two tautomers, viz. 2,7-dihydroxycyclohepta-2,4,6-trien-1-one, (I), and 2,3dihydroxycyclohepta-2,4,6-trien-1-one, (I 0 ) (Tsuji et al, 1999). The crystal structure determination of the title compound, (I), has been undertaken to determine its major tautomer and hydrogen-bonding scheme.…”

Section: Commentmentioning

confidence: 99%

3-Hydroxytropolone (2,7-dihydroxycyclohepta-2,4,6-trien-1-one)

2007

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Section: Commentmentioning

confidence: 99%

3-Hydroxytropolone (2,7-dihydroxycyclohepta-2,4,6-trien-1-one)

2007

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“…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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“…The introduction of a slight asymmetry in the double-minimum potential well drastically decreases the probability of proton tunneling. [20][21][22][23][24][25][26][27][28][29][30] The double-minimum potential well is no longer symmetric in the S 0 state of 5-aminotropolone, 24 and the wave function is completely localized in one well, but the double-minimum potential well is symmetric in the S 1 state and proton tunneling efficiently occurs. The substitution of the OH group at the 5-position of the H atom of TRN͑OH͒ induces significant asymmetry in the double-minimum potential well for both the S 0 and S 1 states.…”

Section: Introductionmentioning

confidence: 99%

“…The relation between the two doubleminimum potential wells is ''reverse asymmetry'' in 5-hydroxytropolone, and proton tunneling efficiently occurs only when the tunneling promoting mode corresponding to the 13 or 14 mode of TRN͑OH͒ is excited. 25, 26 Tsuji et al 27 investigated the effects of the torsional motion of the phenyl group on proton tunneling in 5-phenyltropolone. The torsional motion of the phenyl group strongly couples with the intramolecular proton transfer, and decreases the tunneling splitting of the zero-point level in the S 1 state as compared with that of TRN͑OH͒.…”

Section: Introductionmentioning

confidence: 99%

Tunneling in jet-cooled 5-methyltropolone and 5-methyltropolone–OD. Coupling between internal rotation of methyl group and proton transfer

Nishi

Sekiya

Kawakami

et al. 1999

The Journal of Chemical Physics

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Articles you may be interested inA combined nuclear dynamics and electronic study of the coupling between the internal rotation of the methyl group and the intramolecular proton transfer in 5-methyltropolone Coupling between the internal rotation of the methyl group and proton/deuteron transfer in jet-cooled 5-methyl-9hydroxyphenalenone(OH) and 5-methyl-9-hydroxyphenalenone(OD): Tunneling rate dependence of coupling potentialThe coupling of two large amplitude motions, the internal rotation of the methyl group and the intramolecular proton transfer, has been investigated for jet-cooled 5-methyltropolone, 5-methyltropolone-OD, and the 5-methyltropolone-(H 2 O) 1 1:1 hydrogen-bonded complex by measuring the fluorescence excitation, dispersed fluorescence, and hole-burning spectra in the S 1 -S 0 region. The vibronic bands in the excitation spectrum of 5-methyltropolone consist of four components originating from the transitions between the sublevels in the S 1 and S 0 states. The intensity of the bands, the frequencies, and the change in the stable conformation of the methyl group upon photoexcitation have been analyzed for 5-methyltropolone-(H 2 O) 1 by calculating the one-dimensional periodic potential function, which provides the correlation between the internal rotational levels of 5-methyltropolone-(H 2 O) 1 and the sublevels of 5-methyltropolone. It has been shown that the electronic transitions between the sublevels within the same symmetry are allowed in 5-methyltropolone. The tunneling splitting of the zero-point level in the S 1 state is 2.2 cm Ϫ1 for 5-methyltropolone. The corresponding splitting for 5-methyltropolone-OD is less than 0.5 cm Ϫ1 . A drastic decrease of the tunneling splitting for 5-methyltropolone as compared to that for tropolone ͑19.9 cm Ϫ1 ͒ is ascribed to a strong coupling between the two large amplitude motions in the S 1 state. The existence of a similar coupling has been suggested in the S 0 state of 5-methyltropolone. The excitation of the sublevel in the S 1 state considerably promotes proton tunneling. This effect has been explained by the delocalization of the wave function of the internal rotation of the methyl group. The two-dimensional potential energy surface along the proton transfer coordinate and the rotational angle of the methyl group has been calculated to explain the effects of the coupling on proton tunneling.

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Investigation of intramolecular hydrogen bonds in ortho-hydroxytropolone

Cited by 9 publications

References 31 publications

3-Hydroxytropolone (2,7-dihydroxycyclohepta-2,4,6-trien-1-one)

3-Hydroxytropolone (2,7-dihydroxycyclohepta-2,4,6-trien-1-one)

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

Tunneling in jet-cooled 5-methyltropolone and 5-methyltropolone–OD. Coupling between internal rotation of methyl group and proton transfer

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