Spectral and luminescence properties of derivatives of 2-aryl[9,10]phenanthroxazole

Дорошенко, А. О.; Posokhov, E. A.; Shershukov, V. M.; Mitina, V. G.; Пономарев, О. А.

doi:10.1007/bf01177024

Cited by 8 publications

(21 citation statements)

References 6 publications

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“…This must result also in changes of spectral characteristics of the title compounds in comparison with their oxazolic analogs. 50 The spectral properties of the ortho-hydroxy derivatives of 2,5-diphenyl-1,3,4-oxadiazole in three solvents, Table 2. Spectral characteristics of the ortho-hydroxy derivatives of 2,5-diphenyl-1,3,4-oxadiazole in octane (Oc), toluene (Tol.)…”

Section: Resultsmentioning

confidence: 99%

“…In contrast to the normal forms, phototautomer lifetimes belong to the nanosecond time interval (see Table 3). Based on these facts, we can conclude that for the investigated compounds, as also for the previously studied derivatives of oxazole, 50 and for the most of the other cases known from the literature (see Introduction), the theoretically possible excited state equilibrium is significantly shifted towards the phototautomer form. The seeming exception of compound IV will be discussed later.…”

Section: Compoundmentioning

confidence: 94%

“…50 It could therefore be concluded that effective intramolecular quenching of fluorescence accompanies the ESIPT reaction in the oxadiazole series.…”

Section: Compoundmentioning

confidence: 99%

“…Rate constants of the ESIPT reaction and of radiationless decay in the phototautomer forms estimated on the basis of spectral and kinetic parameters in the series of ortho-hydroxy derivatives of 2,5-diphenyl-1,3,4-oxadiazole (I±VI) and analogous derivatives of 2,5-diphenyl-1,3-oxazole (VII±XIII, recalculated data from Ref. 50 (t PT ):…”

Section: Compoundmentioning

confidence: 99%

“…In a recent paper, 50 we examined the effect of the ESIPT reaction on the fluorescent properties of several ortho-hydroxy derivatives of 2,5-diphenyloxazole. The aim of this work was to investigate how the substitution of an electron-rich oxazole ring with a greater electron acceptor and less basic oxadiazole ring influences the fluorescent properties, the rate of the ESIPT reaction and the efficiency of radiationless decay within the studied series of compounds.…”

Section: Introductionmentioning

confidence: 99%

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Excited state intramolecular proton transfer reaction and luminescent properties of theortho-hydroxy derivatives of 2,5-diphenyl-1,3,4-oxadiazole

Дорошенко

Posokhov

Verezubova

et al. 2000

J. Phys. Org. Chem.

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Luminescent properties of several ortho‐hydroxy derivatives of 2,5‐diphenyl‐1,3,4‐oxadiazole were studied in solvents of different polarity and protolytic ability and compared with the analogous derivatives of 1,3‐oxazole, studied by us earlier. Evaluations of rate constants for the excited state intramolecular proton transfer (ESIPT) reaction and radiationless degradation of the energy of electronic excitation in the ESIPT reaction product, phototautomer form, were made on the basis of fluorescence quantum yields and fluorescence kinetic measurements. The proton phototransfer reaction is the most efficient primary photoprocess in the examined series of compounds. With rate constants of 1011–1012 s−1 it exceeds the rates of other primary photophysical processes in these molecules by up to 2–3 orders of magnitude. A connection between the rate of the ESIPT reaction and the electron density redistribution on electronic excitation was revealed for the molecules under study. The electron donor substituents in 5‐phenyl decrease the proton phototransfer rate constant up to complete inhibition of the ESIPT process in the case of the dimethylamino derivative of the oxazole series, whereas the electron acceptor substituents must accelerate this reaction. The determining role of the excited state increase of the proton donor group acidity was assumed on the basis of experimental data and quantum chemical calculations. The temperature investigations showed that the ESIPT reaction in the series of ortho‐hydroxy derivatives of 2,5‐diphenyloxazole and 2,5‐diphenyl‐1,3,4‐oxadiazole has a very low activation barrier. However, the radiationless processes in the phototautomer form are characterized by the presence of a certain barrier in both examined series. A dependence of the radiationless dissipation rate in the phototautomer form on the excited state redistribution of the electron density in it was also found. The more efficient is the charge transfer from the ortho‐phenolate fragment to the protonated heterocycle and the rest of the molecule, the more efficient are the radiationless losses. It was revealed that structural changes, which prevent the mentioned movement of electron density, result in an increase in the fluorescence efficiency of the phototautomer form and, hence, also to an increase in the total fluorescence quantum yield of the ESIPT molecule. Copyright © 2000 John Wiley & Sons, Ltd.

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Section: Resultsmentioning

confidence: 99%

Section: Compoundmentioning

confidence: 94%

“…50 It could therefore be concluded that effective intramolecular quenching of fluorescence accompanies the ESIPT reaction in the oxadiazole series.…”

Section: Compoundmentioning

confidence: 99%

Section: Compoundmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Excited state intramolecular proton transfer reaction and luminescent properties of theortho-hydroxy derivatives of 2,5-diphenyl-1,3,4-oxadiazole

Дорошенко

Posokhov

Verezubova

et al. 2000

J. Phys. Org. Chem.

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Excited‐State Intramolecular Proton Transfer in 2‐(2′‐Hydroxyphenyl)benzoxazole Derivatives

Pang

2010

Hydrogen Bonding and Transfer in the Excited State

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A detailed DFT/TDDFT study on excited‐state intramolecular hydrogen bonding dynamics and proton‐transfer mechanism of 2‐phenanthro[9,10‐d]oxazol‐2‐yl‐phenol

Zhang

Yang

Jia

et al. 2018

J of Physical Organic Chem

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In this present work, using density functional theory and time-dependent density functional theory methods, we theoretically study the excited-state hydrogen bonding dynamics and the excited state intramolecular proton transfer mechanism of a new 2-phenanthro[9,10-d]oxazol-2-yl-phenol (2PYP) system.Via exploring the reduced density gradient versus sign(λ 2 (r))ρ(r), we affirm that the intramolecular hydrogen bond O1-H2⋯N3 is formed in the ground state.Based on photoexcitation, comparing bond lengths, bond angles, and infrared vibrational spectra involved in hydrogen bond, we confirm that the hydrogen bond O1-H2⋯N3 of 2PYP should be strengthened in the S 1 state. Analyses about frontier molecular orbitals prove that charge redistribution of 2PYP facilitates excited state intramolecular proton transfer process. Via constructing potential energy curves and searching transition state structure, we clarify the excited state intramolecular proton transfer mechanism of 2PYP in detail, which may make contributions for the applications of such kinds of system in future.

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Spectral and luminescence properties of derivatives of 2-aryl[9,10]phenanthroxazole

Cited by 8 publications

References 6 publications

Excited state intramolecular proton transfer reaction and luminescent properties of theortho-hydroxy derivatives of 2,5-diphenyl-1,3,4-oxadiazole

Excited state intramolecular proton transfer reaction and luminescent properties of theortho-hydroxy derivatives of 2,5-diphenyl-1,3,4-oxadiazole

Excited‐State Intramolecular Proton Transfer in 2‐(2′‐Hydroxyphenyl)benzoxazole Derivatives

A detailed DFT/TDDFT study on excited‐state intramolecular hydrogen bonding dynamics and proton‐transfer mechanism of 2‐phenanthro[9,10‐d]oxazol‐2‐yl‐phenol

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