Excited state proton transfer in 2-heteroaryloxazoles. The principle of least photochemical motion

Druzhinin, S. I.; Krashakov, S. A.; Troyanovsky, Igor V.; Uzhinov, B. M.

doi:10.1016/0301-0104(87)80085-x

Cited by 10 publications

(4 citation statements)

References 5 publications

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“…29 The rate constants for the protonation of pyridine and oxazole derivatives in the excited state by carboxylic acids are one or two orders of magnitude smaller than the rate constants for the diffusionlimited reactions, respectively. 30,31 The photoprotonation of pyridine and oxazole derivatives occurs either according to the static [reaction (5)] or dynamic [reaction (4)] mechanism. 30,31 The kinetic and thermodynamic parameters for the reactions (4) and ( 5) and spectral-kinetic characteristic of the forms B and BH + for the known laser acid-base systems are listed in Table 2.…”

Section: An Operation Scheme For a Photochemical Laser Based On Proto...mentioning

confidence: 99%

“…30,31 The photoprotonation of pyridine and oxazole derivatives occurs either according to the static [reaction (5)] or dynamic [reaction (4)] mechanism. 30,31 The kinetic and thermodynamic parameters for the reactions (4) and ( 5) and spectral-kinetic characteristic of the forms B and BH + for the known laser acid-base systems are listed in Table 2.…”

Section: An Operation Scheme For a Photochemical Laser Based On Proto...mentioning

confidence: 99%

“…40 However, solutions with simultaneous efficient fluorescence of both the initial heteryloxazole and cation, do not lase at certain ratio of the components. As the concentration of a proton donor (acetic acid) in ethanolic solutions of 2-heteryloxazoles is increased, the quantum yields of fluorescence of the initial form are decreased, and a band of fluorescence of a protonated form resulting from the proton phototransfer appears in the longwave region of the spectrum, 30 and the efficiency of laser radiation of the initial form drops to zero at low concentrations of acetic acid. At certain concentrations, both forms do not lase.…”

Section: Losses In Photochemical Lasersmentioning

confidence: 99%

See 2 more Smart Citations

Excited state proton transfer dye lasers

Uzhinov¹,

Druzhinin²

1998

Russ. Chem. Rev.

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Section: An Operation Scheme For a Photochemical Laser Based On Proto...mentioning

confidence: 99%

Section: An Operation Scheme For a Photochemical Laser Based On Proto...mentioning

confidence: 99%

Section: Losses In Photochemical Lasersmentioning

confidence: 99%

See 1 more Smart Citation

Excited state proton transfer dye lasers

Uzhinov¹,

Druzhinin²

1998

Russ. Chem. Rev.

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“…Pyridyl-substituted phenyloxazoles were used earlier as model compounds for the study of static and dynamic intermolecular proton transfer [1]. The N(CH 3 ) 2 -substituted oxazole-oxadiazoles were seen as organic luminophores with an abnormally large fluorescence Stokes shift (up to 14,700 cm −1 in MeCN) [2].…”

Section: Introductionmentioning

confidence: 99%

Intramolecular photo-driven charge transfer in a series of pyridyl substituted phenyloxazoles. Structural relaxation in meta-substituted ethylpyridinium derivative of phenyloxazole

Volchkov

Khimich

Rusalov

et al. 2021

Photochem Photobiol Sci

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A series of pyridyl (pyridinium) substituted benzoxazoles were studied by steady state absorption, fluorescence spectroscopy, time-resolved fluorescence spectroscopy, fs pulse absorption and polarization spectroscopy, and quantum-chemical calculations. The spectral and kinetic parameters of the fluorophores in MeCN and EtOAc were obtained experimentally and were calculated by means of DFT and TDDFT methods. A scheme including four transient excited states was proposed for the interpretation of differential absorption kinetics of the charged fluorophores. Expressions describing the actual kinetics graphs, the decay associated spectra, and the species-associated spectra were derived. The charge shift step was found to be dependent on average solvation times. A charge shift followed by the formation of the twisted conformer was found for the excited 1-ethyl-3-(5-phenyloxazol-2-yl)pyridinium 4-methyl-1-benzenesulfonate in MeCN and EtOAc. Conformational analysis confirms a large amplitude motion of the meta-substituted ethylpyridinium group as an additional structural relaxation path producing an abnormally large fluorescence Stokes shift.

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Structure and Photochemical Properties of r‐1, c‐2, t‐3, t‐4‐l, 3‐Bis [2‐ (5‐R‐benzoxazolyl) ] −2,4‐di (4‐R' ‐phenyl) cyclobutane

Zhang

Zhuang

et al. 2001

Chin. J. Chem.

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molecule of IIc is centmsymmetric, which indicates that the dimerization process is a head-btail fahion. The selectivity of the photodimerization of Ia-Ic has been enhanced by using acidic solvent and the reaction speed would be decreased when electron donating gnxlp was introduced in the Qposition of the phenyl group. That the photodimerization is not affected by the presence of oxygen as well as its high stereo-selectivity demonstrated that the reaction proceeded through an excited singlet state. It was also found that under irradiation of short wavelength U V , these dimers underwent photolysis completely to reproduce its bnns-monomers, and then the new formed species changed into their ck-isomers through m -c k isomehtion.

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Excited state proton transfer in 2-heteroaryloxazoles. The principle of least photochemical motion

Cited by 10 publications

References 5 publications

Excited state proton transfer dye lasers

Excited state proton transfer dye lasers

Intramolecular photo-driven charge transfer in a series of pyridyl substituted phenyloxazoles. Structural relaxation in meta-substituted ethylpyridinium derivative of phenyloxazole

Structure and Photochemical Properties of r‐1, c‐2, t‐3, t‐4‐l, 3‐Bis [2‐ (5‐R‐benzoxazolyl) ] −2,4‐di (4‐R' ‐phenyl) cyclobutane

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