Direct observation of the nuclear motion during ultrafast intramolecular proton transfer

Lochbrunner, Stefan; Stock, Kai; Riedle, Eberhard

doi:10.1016/j.molstruc.2004.01.038

Cited by 72 publications

(67 citation statements)

References 22 publications

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“…We obtained very similar experimental results for HBO [29], OHBA [35], and HAN [36] (see Fig. 11.6 and 11.7).…”

Section: Characteristic Features Of the Transient Absorptionsupporting

confidence: 73%

“…In order to uncover the characteristic features of the ESIPT dynamics and to develop a universal model we investigated a series of molecules with a longer S 1 lifetime [27][28][29]. Two of them, HBT and HBO have a nitrogen atom as proton acceptor while in the other two, OHBA and 1-hydroxy-2-acetonaphtone (HAN) the proton switches between two oxygen atoms (see Fig.…”

Section: Spectral Signatures Of Ultrafast Esiptmentioning

confidence: 99%

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Direct Observation of Nuclear Motion during Ultrafast Intramolecular Proton Transfer

Lochbrunner¹,

and²,

Riedle³

2006

Hydrogen‐Transfer Reactions

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“…We obtained very similar experimental results for HBO [29], OHBA [35], and HAN [36] (see Fig. 11.6 and 11.7).…”

Section: Characteristic Features Of the Transient Absorptionsupporting

confidence: 73%

Section: Spectral Signatures Of Ultrafast Esiptmentioning

confidence: 99%

Direct Observation of Nuclear Motion during Ultrafast Intramolecular Proton Transfer

Lochbrunner¹,

and²,

Riedle³

2006

Hydrogen‐Transfer Reactions

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“…Many research studies have been devoted to studying the dynamics of the ultrafast ESIPT process in the first excited singlet state of HBI, HBO, and HBT, both theoretically and experimentally. [4][5][6]8,[23][24][25][26][27][28][38][39][40][41][42] The slower dynamics of the proton-transferred tautomer in the picosecond to microsecond time range also has received much attention, including detailed studies of the tautomerization in the triplet state, for which only scarce studies exist for other ESIPT molecules. [4][5][6][7][9][10][11][12][13][14][15][16][17][18][29][30][31][32][33][34][35][36][37][38] Despite the general similarities observed for the o-hydroxyphenylbenzazoles, markedly different fluorescence quantum yields and lifetimes were measured for these compounds, much higher values being observed for HBI than for HBO and HBT.…”

Section: Introductionmentioning

confidence: 99%

Excited-State Intramolecular Proton Transfer in 2-(3‘-Hydroxy-2‘-pyridyl)benzoxazole. Evidence of Coupled Proton and Charge Transfer in the Excited State of Some o-Hydroxyarylbenzazoles

et al. 2007

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The influence of solvent, temperature, and viscosity on the phototautomerization processes of a series of o-hydroxyarylbenzazoles was studied by means of ultraviolet-visible (UV-vis) absorption spectroscopy and steady-state and time-resolved fluorescence spectroscopy. The compounds studied were 2-(2'-hydroxyphenyl)benzimidazole (HBI), 2-(2'-hydroxyphenyl)benzoxazole (HBO), 2-(2'-hydroxyphenyl)benzothiazole (HBT), 2-(3'-hydroxy-2'-pyridyl)benzimidazole (HPyBI), and the new derivative 2-(3'-hydroxy-2'-pyridyl)benzoxazole (HPyBO), this one studied in neutral and acid media. All of these compounds undergo an excited-state intramolecular proton transfer (ESIPT) from the hydroxyl group to the benzazole N3 to yield an excited tautomer in syn conformation. A temperature- and viscosity-dependent radiationless deactivation of the tautomer has been detected for all compounds except HBI and HPyBI. We show that this radiationless decay also takes place for 2-(3-methyl-1,3-benzothiazol-3-ium-2-yl)benzenolate (NMeOBT), the N-methylated analog of the tautomer, whose ground-state structure has anti conformation. In ethanol, the radiationless decay shows intrinsic activation energy for HPyBO and HBO; however, it is barrierless for HBT and NMeOBT and controlled instead by the solvent dynamics. The relative efficiency of the radiationless decay in the series of molecules studied supports the hypothesis that this transition is connected with a charge-transfer process taking place in the tautomer, its efficiency being related to the strength of the electron donor (dissociated phenol or pyridinol moiety) and electron acceptor (protonated benzazole). We propose that the charge transfer is associated with a large-amplitude conformational change of the tautomer, the process leading to a nonfluorescent charge-transfer intermediate. The previous ESIPT step generates the structure with the suitable redox pair to undergo the charge-transfer process; therefore, an excited-state intramolecular coupled proton and charge transfer takes place for these compounds.

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“…Recently, however, for typical ESIPT molecules such as 2-(2'-hydroxyphenyl)benzothiazole and 10-hydroxybenzo [h]quinoline that undergo ultrafast ESIPT, coherent excitations of low frequency skeletal vibrations on the PES of the reaction product have been reported by femtosecond spectroscopies. [4][5][6][7] Based on those experiments, a multi-dimensional picture for the PES of the ESIPT was proposed. [8][9][10] In this model, vibrational modes involving large amplitude skeletal deformation shorten the distance between the proton and the proton acceptor, and promote the proton transfer.…”

Section: Introductionmentioning

confidence: 99%

Ultrafast Excited State Intramolecular Proton Transfer Dynamics of 1-Hydroxyanthraquinone in Solution

Ryu¹,

Kim²,

Kim³

et al. 2013

Bulletin of the Korean Chemical Society

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Proton transfer reaction is one of the most fundamental processes in chemistry and life science. Excited state intramolecular proton transfer (ESIPT) has been studied as a model system of the proton transfer, since it can be conveniently initiated by light. We report ESIPT reaction dynamic of 1-hydroxy-anthraquione (1-HAQ) in solution by highly time-resolved fluorescence. ESIPT time of 1-HAQ is determined to be 45 ± 10 fs directly from decay of the reactant fluorescence and rise of the product fluorescence. High time resolution allows observation of the coherent vibrational wave packet motion in the excited state of the reaction product tautomer. The coherently excited vibrational mode involves large displacement of the atoms, which shortens the distance between the proton donor and the acceptor. With the theoretical analysis, we propose that the ESIPT of 1-HAQ proceeds barrierlessly with assistance of the skeletal vibration, which in turn becomes excited coherently by the ESIPT reaction.

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Direct observation of the nuclear motion during ultrafast intramolecular proton transfer

Cited by 72 publications

References 22 publications

Direct Observation of Nuclear Motion during Ultrafast Intramolecular Proton Transfer

Direct Observation of Nuclear Motion during Ultrafast Intramolecular Proton Transfer

Excited-State Intramolecular Proton Transfer in 2-(3‘-Hydroxy-2‘-pyridyl)benzoxazole. Evidence of Coupled Proton and Charge Transfer in the Excited State of Some o-Hydroxyarylbenzazoles

Ultrafast Excited State Intramolecular Proton Transfer Dynamics of 1-Hydroxyanthraquinone in Solution

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