Electronic spectra of jet-cooled 3- and 4-chlorotropolones in the <i>S</i>1–<i>S</i> region. Inhibition of proton tunneling by asymmetric substitution

Tsuji, Takeshi; Sekiya, Hiroshi; Ito, Sayaka; Ujita, Hiroki; Habu, Mariko; Mori, Akira; Takeshita, Hitoshi; Nishimura, Yukio

doi:10.1063/1.464800

Cited by 18 publications

(15 citation statements)

References 8 publications

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“…Spectral doublets are absent for the jet-cooled asymmetrical molecules because there is a large asymmetry offset of the energy minima of the double-well PESs [47]. Observations for the ZP, out-of-plane deformation, and nominal O_O stretching spectral doublets are shown in Table 1.4 [48].…”

Section: Discussionmentioning

confidence: 99%

“…Sekiya and his collaborators [44][45][46][47][48] found spectral doublets in the S 1 -S 0 excitation and dispersed fluorescence spectra of jet-cooled halotropolones that are modifications of the basic coherent tunneling splittings observed for TRN(OH) and TRN(OD). The symmetrical chlorotropolones showed enhancements of the spec- 5-bromo-TRN(OD) 2 £1…”

Section: Tropolone Derivativesmentioning

confidence: 99%

“…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%

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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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Section: Discussionmentioning

confidence: 99%

Section: Tropolone Derivativesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

Redington

2006

Hydrogen‐Transfer Reactions

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“…1-3 The effects of the substitution on proton tunneling have been studied in various tropolone derivatives. [4][5][6][7] The coupling of two large amplitude motions, internal rotation of the methyl group and transferring proton motion, has long been an intriguing subject for both experimental and theoretical chemists. [8][9][10][11] Four sublevels of the vibrationless state were observed in 2-methylmalonaldehyde by measuring the microwave spectrum.…”

Section: ͓S0021-9606͑98͒03329-7͔mentioning

confidence: 99%

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

Nishi

Sekiya

Kawakami

et al. 1998

The Journal of Chemical Physics

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A combined nuclear dynamics and electronic study of the coupling between the internal rotation of the methyl group and the intramolecular proton transfer in 5-methyltropoloneCoupling 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 potential Tunneling in jet-cooled 5-methyltropolone and 5-methyltropolone-OD. Coupling between internal rotation of methyl group and proton transfer

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“…[1][2][3][4][5][6] In addition to TRN, intramolecular hydrogen bonds of substituted tropolones have been investigated. [7][8][9][10][11][12][13][14][15][16] It is interesting to know the electronic and steric effects of substituents on proton tunneling and/or proton transfer. An interesting feature of the substituted tropolones is their isomerism.…”

Section: Introductionmentioning

confidence: 99%

Investigation of intramolecular hydrogen bonds in ortho-hydroxytropolone

Tsuji

Hamabe

Hayashi

et al. 1999

The Journal of Chemical Physics

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Articles you may be interested inA comparative computational study of hydrogen and lithium-bonded complexes Hydrogen-bonded OH stretching modes of methanol clusters: A combined IR and Raman isotopomer studyThe weak hydrogen bond in the fluorobenzene-ammonia van der Waals complex: Insights into the effects of electron withdrawing substituents on π versus in-plane bonding J. Chem. Phys. 126, 154319 (2007); 10.1063/1.2714554High-level ab initio calculations for the four low-lying families of minima of ( H 2 O ) 20 . II. Spectroscopic signatures of the dodecahedron, fused cubes, face-sharing pentagonal prisms, and edge-sharing pentagonal prisms hydrogen bonding networksThe S 0 -S 1 electronic spectra of ortho-hydroxytropolone (o-OHTR) in supersonic jets were measured in order to study its isomerism. Only one isomer has been detected in a supersonic jet. A blue shift of electronic origin due to deuteration of two -OH groups was twice as large as that of one -OH group, suggesting that the configurations of the two -OH groups in o-OHTR are equivalent. This finding is consistent with the results of the ab initio calculations. The origin bands of the complexes with water and acetone were red-shifted from that of the bare molecule. The red-shift was explained in terms of two opposite effects of formation of an intermolecular hydrogen bond on each of two intramolecular hydrogen bonds.

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Electronic spectra of jet-cooled 3- and 4-chlorotropolones in the S1–S region. Inhibition of proton tunneling by asymmetric substitution

Cited by 18 publications

References 8 publications

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

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

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

Investigation of intramolecular hydrogen bonds in ortho-hydroxytropolone

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