Intramolecular proton transfer of a 2-(2′,4′-dinitrobenzyl)pyridine studied by femtosecond transient absorption spectroscopy

Takeda, Jun; Chung, Dutch D.; Zhou, Jieyu; Nelson, Keith A.

doi:10.1016/s0009-2614(98)00506-5

Cited by 10 publications

(8 citation statements)

References 30 publications

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“…1 µs (Figure 7)), as expected for the ultrafast photoinduced proton transfer from the CH to NH tautomer. 2,5 The rest grew-in on a longer time scale. Detailed kinetic studies were not carried out on the Ar-saturated solution, but with the aerated solution of 1.03 × 10 -3 M DNBP, the grow-in did not appear to fit either first-or second-order kinetics.…”

Section: Flash Photolysis Experimentsmentioning

confidence: 99%

New Insights on the Photochromism of 2-(2‘,4‘-Dinitrobenzyl)pyridine

2002

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The photochromic behavior of 2-(2′,4′-dinitrobenzyl)pyridine (R-DNBP) has been followed in poly(methyl methacrylate) (PMMA) films and benzene solutions to clarify the behavior of a precursor state, previously identified in studies on crystalline R-DNBP at low temperatures. In PMMA films, photolysis at temperatures e50 K led to the concurrent formation of a NH tautomer and a colorless intermediate, which was stable for several hours. On irradiation at low temperatures and warming the sample, the colorless intermediate was seen to react to produce the NH tautomer in a higher yield than that found in the direct photolysis. Further information on this intermediate has come from flash photolysis studies in benzene solution, in which a new transient absorption has been observed at 335 nm and assigned to this species. This decays within a few microseconds at room temperature to form an OH tautomer, which then interconverts to the NH tautomer. The precursor state is not quenched by oxygen or naphthalene. From consideration of the kinetic and spectral data, it is suggested that this new species corresponds to a nonrelaxed tautomeric form of the OH state of R-DNBP.

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Section: Flash Photolysis Experimentsmentioning

confidence: 99%

New Insights on the Photochromism of 2-(2‘,4‘-Dinitrobenzyl)pyridine

2002

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“…The researchers cited above consider that the proton transfer takes place in electronically excited states. A different point of view is expressed by Takeda et al, 121 who studied intramolecular proton transfer in 2-(2 H ,4 H -dinitrophenyl)pyridine; they assumed that no intermediate or final products in excited states are formed. Only three different intermediate photoinduced absorption spectra were observed in the experiments.…”

Section: } }mentioning

confidence: 99%

“…122,123 In our opinion, the absence of excited intermediate species is unlikely. The assumption of the researchers cited 121 is based on the fact that they did not observe any luminescence. However, we have considered above a model of photoisomerisation of spiro compounds in which photoinduced absorption by the intermediate electronically excited product without luminescence was recorded.…”

Section: } }mentioning

confidence: 99%

Femtochemistry

Sarkisov¹,

Umanskii²

2001

Russ. Chem. Rev.

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“…Many studies on the photochromic reaction of α-DNBP have been reported. Flash photolysis, − UV–vis absorption spectroscopy, , polarized optical absorption spectroscopy, femtosecond transient absorption spectroscopy, , time-resolved resonance Raman spectroscopy, − and resonance coherent anti-Stokes Raman scattering (CARS) spectroscopy methods have been implemented to study the photochromic reaction of α-DNBP and its derivatives. X-ray diffraction studies have determined the crystal structure of the CH form (Figure top), , but not of the NH and OH isomers because of the instability of the NH form (Figure bottom right) and the OH form (Figure bottom left).…”

Section: Introductionmentioning

confidence: 99%

Vibrational Spectroscopic Characterization of 2-(2,4-Dinitrobenzyl)-pyridine (α-DNBP) in Solution by Polarization-Resolved Spontaneous Raman Scattering and Broadband CARS

2019

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The photochromic molecule 2-(2,4-dinitro-benzyl)-pyridine (α-DNBP) is characterized in solution by a combination of density functional theory employing a polarizable continuum model and polarization-resolved spontaneous and nonlinear Raman spectroscopies. By the comparison of theoretically predicted wavenumber positions and depolarization ratios with the experimental spectra acquired under electronically nonresonant conditions, polarized and depolarized Raman bands are assigned. Specifically, the symmetric stretching vibrations of the two nitro groups in ortho and para positions to the pyridine ring can be experimentally differentiated, mainly because of their different Raman depolarization ratios, which supports our prediction from theory. Compared to the polarization-resolved spontaneous Raman experiments, the vibrational spectroscopic differentiation of the two nitro groups is more pronounced in time-delayed polarization-resolved coherent anti-Stokes Raman scattering experiments. Overall, this linear and nonlinear vibrational spectroscopic characterization of the CH form paves the way for the interpretation of future time-resolved pump/nonlinear Raman probe studies on the ultrafast photoinduced intramolecular proton transfer in α-DNBP involving a nitro group as an intramolecular proton acceptor.

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Intramolecular proton transfer of a 2-(2′,4′-dinitrobenzyl)pyridine studied by femtosecond transient absorption spectroscopy

Cited by 10 publications

References 30 publications

New Insights on the Photochromism of 2-(2‘,4‘-Dinitrobenzyl)pyridine

New Insights on the Photochromism of 2-(2‘,4‘-Dinitrobenzyl)pyridine

Femtochemistry

Vibrational Spectroscopic Characterization of 2-(2,4-Dinitrobenzyl)-pyridine (α-DNBP) in Solution by Polarization-Resolved Spontaneous Raman Scattering and Broadband CARS

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