Electronic structure and nature of the bands in electronic absorption spectra of stable phenoxyl radicals of indophenoxyl and galvinoxyl

Degtyarev, L. S.

doi:10.1007/bf00534613

Cited by 2 publications

(4 citation statements)

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“…The calculated 0.9 eV energy of the first state contrasts with former CNDO/S calculations that located this np transition at 2 eV and that found the first electronic state to be a pp transition at 1.4 eV. 17 The first observable electronic absorption band at 860 nm (1.4 eV) is thus assigned to the D 3 ' D 0 transition. This band as well as that at 770 nm, that can be ascribed to the D 4 ' D 0 transition, both have pp character.…”

Section: Resultscontrasting

confidence: 74%

“…17 On the other hand, such a long lifetime agrees well with the occurrence of photoinduced disproportionation, which, as it involves the diffusive encounter of two galvinoxyl molecules, is only possible if the D 1 state of galvinoxyl is sufficiently long-lived.…”

Section: Introductionmentioning

confidence: 52%

“…14 From these measurements, the lifetime of the D 1 state was estimated to be on the order of tens of microseconds, 14 an astonishingly high value considering that the D 1 state of galvinoxyl is, according to CNDO/S calculations, only 1.4 eV above its ground state. 17 On the other hand, such a long lifetime agrees well with the occurrence of photoinduced disproportionation, which, as it involves the diffusive encounter of two galvinoxyl molecules, is only possible if the D 1 state of galvinoxyl is sufficiently long-lived.…”

Section: Introductionmentioning

confidence: 52%

“…10 The lowest energy transition observed in the electronic absorption spectrum is located at 860 nm (1.4 eV), 5 in agreement with CNDO/S quantum chemical calculations that found the lowest excited state at the same energy. 17 Galvinoxyl is a phenoxyl type radical and, apart from one publication 18 about the fluorescence of 2,4,6-tris(tert-butyl)phenoxyl radical that has been questioned later on, 19,20 no emission has been reported for this family of radicals. This is in contrast to, for example, the structurally similar diphenylmethyl type radicals, many of which emit around B550 nm (2.3 eV) in room temperature solution.…”

Section: Introductionmentioning

confidence: 99%

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Photophysics of the galvinoxyl free radical revisited

Grilj

Zonca

Daku

et al. 2012

Phys. Chem. Chem. Phys.

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The photophysical properties of the free neutral radical galvinoxyl were studied by a combination of femtosecond time-resolved spectroscopy and quantum chemical calculations. The electronic absorption spectrum is dominated by an intense band at 430 nm that is ascribed to the D 9,10 ' D 0 transitions. Upon photoexcitation at 400 nm, the population of the D 9,10 states decays within less than 200 fs to the electronic ground state. This ultrafast internal conversion does not involve intramolecular modes with large amplitude motion as the measured dynamics does not show any significant dependence on the environment, but is most probably facilitated by a high density of electronic states of different character. Depending on the solvent, a weak transient band due to the galvinoxylate anion is also observed. This closed-shell species, which is fluorescent although its deactivation is also dominated by non-radiative decay, is generated upon biphotonic ionization of the solvent and electron capture. The ultrashort excited-state lifetime of the galvinoxyl radical precludes photoinduced disproportionation previously claimed to be at the origin of the formation of both anion and cation.

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Section: Resultscontrasting

confidence: 74%

Section: Introductionmentioning

confidence: 52%