Structural changes in excited states and photoisomers determined by time-resolved Raman scattering

Takahashi, Hiroaki; Werncke, W.; Pfeiffer, M.; Lau, A.; Johr, T.

doi:10.1007/bf01081063

Cited by 7 publications

(8 citation statements)

References 24 publications

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“…Concerning the most intense bands, these spectra are comparable with those obtained by Takahashi et al for the spectral region 1100-1600 cm -1 by nanosecond pump and probe excitations at a delay of 0 ns. 25 However, new weak lines are observed in the present investigation, in particular, the 1376 cm -1 in the TMPD-h 16 spectrum. In Figure 3 are compared the resonance Raman spectra of the excited S 1 state (probed at 752 nm), excited T 1 state (probed at 610 nm), 18 and radical cation (probed at 647 nm) 18 of TMPD-h 16 .…”

Section: Resultsmentioning

confidence: 99%

“…A brief discussion of time-resolved resonance Raman spectra of S 1 TMPD has been previously reported. 25 However, this investigation was limited to a very narrow spectral range (1100-1600 cm -1 ). In this paper, we present a comprehensive analysis of the S 1 state time-resolved resonance Raman spectra obtained for four isotopomers of the TMPD and TMB diamines: the fully hydrogenated and ring-or methyl-deuterated or both derivatives.…”

Section: Introductionmentioning

confidence: 99%

“…We are now interested by the TMPD and TMB lowest excited singlet state S 1 responsible for the monophotonic ionization. A brief discussion of time-resolved resonance Raman spectra of S 1 TMPD has been previously reported . However, this investigation was limited to a very narrow spectral range (1100−1600 cm -1 ).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Excited Singlet (S₁) State Resonance Raman Analysis of N,N,N‘,N‘-Tetramethylbenzidine and N,N,N‘,N‘-Tetramethyl-p-phenylenediamine

et al. 2003

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Vibrational data on the first excited singlet state (S1) of N,N,N‘,N‘-tetramethylbenzidine (TMB) and N,N,N‘,N‘-tetramethyl-p-phenylenediamine (TMPD) have been obtained by using picosecond time-resolved Raman spectroscopy for different isotopic derivatives and for the N,N,N‘,N‘-tetraethyl analogues, TEB and TEPD. Reliable vibrational assignments are proposed. On this basis, the S1 state structure and electronic configuration of these diamines are discussed and compared with the results previously reported for the ground state, the lowest excited triplet state, and the radical cation species.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Excited Singlet (S₁) State Resonance Raman Analysis of N,N,N‘,N‘-Tetramethylbenzidine and N,N,N‘,N‘-Tetramethyl-p-phenylenediamine

et al. 2003

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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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“…The technical and scientific growth using TR3 as a technique has been reported from time to time in past few decades. [28][29][30][31][32][33][34][35][36][37][38][39][40][41]…”

Section: Introductionmentioning

confidence: 99%

Time-Resolved Resonance Raman Spectroscopy: Exploring Reactive Intermediates

2011

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The study of reaction mechanisms involves systematic investigations of the correlation between structure, reactivity, and time. The challenge is to be able to observe the chemical changes undergone by reactants as they change into products via one or several intermediates such as electronic excited states (singlet and triplet), radicals, radical ions, carbocations, carbanions, carbenes, nitrenes, nitrinium ions, etc. The vast array of intermediates and timescales means there is no single "do-it-all" technique. The simultaneous advances in contemporary time-resolved Raman spectroscopic techniques and computational methods have done much towards visualizing molecular fingerprint snapshots of the reactive intermediates in the microsecond to femtosecond time domain. Raman spectroscopy and its sensitive counterpart resonance Raman spectroscopy have been well proven as means for determining molecular structure, chemical bonding, reactivity, and dynamics of short-lived intermediates in solution phase and are advantageous in comparison to commonly used time-resolved absorption and emission spectroscopy. Today time-resolved Raman spectroscopy is a mature technique; its development owes much to the advent of pulsed tunable lasers, highly efficient spectrometers, and high speed, highly sensitive multichannel detectors able to collect a complete spectrum. This review article will provide a brief chronological development of the experimental setup and demonstrate how experimentalists have conquered numerous challenges to obtain background-free (removing fluorescence), intense, and highly spectrally resolved Raman spectra in the nanosecond to microsecond (ns-μs) and picosecond (ps) time domains and, perhaps surprisingly, laid the foundations for new techniques such as spatially offset Raman spectroscopy.

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Structural changes in excited states and photoisomers determined by time-resolved Raman scattering

Cited by 7 publications

References 24 publications

Excited Singlet (S₁) State Resonance Raman Analysis of N,N,N‘,N‘-Tetramethylbenzidine and N,N,N‘,N‘-Tetramethyl-p-phenylenediamine

Excited Singlet (S₁) State Resonance Raman Analysis of N,N,N‘,N‘-Tetramethylbenzidine and N,N,N‘,N‘-Tetramethyl-p-phenylenediamine

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

Time-Resolved Resonance Raman Spectroscopy: Exploring Reactive Intermediates

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Structural changes in excited states and photoisomers determined by time-resolved Raman scattering

Cited by 7 publications

References 24 publications

Excited Singlet (S1) State Resonance Raman Analysis of N,N,N‘,N‘-Tetramethylbenzidine and N,N,N‘,N‘-Tetramethyl-p-phenylenediamine

Excited Singlet (S1) State Resonance Raman Analysis of N,N,N‘,N‘-Tetramethylbenzidine and N,N,N‘,N‘-Tetramethyl-p-phenylenediamine

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

Time-Resolved Resonance Raman Spectroscopy: Exploring Reactive Intermediates

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About

Excited Singlet (S₁) State Resonance Raman Analysis of N,N,N‘,N‘-Tetramethylbenzidine and N,N,N‘,N‘-Tetramethyl-p-phenylenediamine

Excited Singlet (S₁) State Resonance Raman Analysis of N,N,N‘,N‘-Tetramethylbenzidine and N,N,N‘,N‘-Tetramethyl-p-phenylenediamine