Electronic spectroscopy of N- and C-substituted chlorocarbazoles in homogeneous media and in solid matrix

SERGIO M. BONESI, ROSA ERRA-BALSELLS

JOURNAL OF LUMINESCENCE

Elsevier

Lugar: North-Holland; Año: 2002 vol. 97 p. 83 - 101

0022-2313

Abstract Electronic spectra (absorption, fluorescence and phosphorescence emission spectra) of chlorocarbazoles 1a–e, 2a–b, 3a, 4a–b, 5a, 6a, 7a, 8a–c, 9a and 9b in acetonitrile and in solid matrix have been recorded at 298 and 77 K. The dynamic properties of the lowest excited singlet and triplet states in term of fluorescence and phosphorescence lifetime, tf and tp; fluorescence and phosphorescence quantum yield, ff and fp have been measured in the same experimental conditions and from these data the radiative and the radiationless rate constants (k0ff and tp; fluorescence and phosphorescence quantum yield, ff and fp have been measured in the same experimental conditions and from these data the radiative and the radiationless rate constants (k0fk0f ; kisc; k0fkisc; k0f ð77Þ; kiscð77Þ; k0 p and k0 nr) and the intersystem crossing quantum yield, fisc; were derived. The intramolecular heavy atom effect (HAE) on the spectroscopic data and photophysical rate constant was analyzed and the incorporation of chlorine atoms to the carbazole moiety proved their ability to quench the fluorescence emission by spin-orbital coupling. The values of the HOMO and LUMO energy, the oscillator strength ( f ) and the lmaxðabsÞ associated to the electronic transitions, the heat of formation of the chlorocarbazoles and the corresponding radical cation (DHf and77Þ; kiscð77Þ; k0 p and k0 nr) and the intersystem crossing quantum yield, fisc; were derived. The intramolecular heavy atom effect (HAE) on the spectroscopic data and photophysical rate constant was analyzed and the incorporation of chlorine atoms to the carbazole moiety proved their ability to quench the fluorescence emission by spin-orbital coupling. The values of the HOMO and LUMO energy, the oscillator strength ( f ) and the lmaxðabsÞ associated to the electronic transitions, the heat of formation of the chlorocarbazoles and the corresponding radical cation (DHf andand k0 nr) and the intersystem crossing quantum yield, fisc; were derived. The intramolecular heavy atom effect (HAE) on the spectroscopic data and photophysical rate constant was analyzed and the incorporation of chlorine atoms to the carbazole moiety proved their ability to quench the fluorescence emission by spin-orbital coupling. The values of the HOMO and LUMO energy, the oscillator strength ( f ) and the lmaxðabsÞ associated to the electronic transitions, the heat of formation of the chlorocarbazoles and the corresponding radical cation (DHf and) and the intersystem crossing quantum yield, fisc; were derived. The intramolecular heavy atom effect (HAE) on the spectroscopic data and photophysical rate constant was analyzed and the incorporation of chlorine atoms to the carbazole moiety proved their ability to quench the fluorescence emission by spin-orbital coupling. The values of the HOMO and LUMO energy, the oscillator strength ( f ) and the lmaxðabsÞ associated to the electronic transitions, the heat of formation of the chlorocarbazoles and the corresponding radical cation (DHf andfisc; were derived. The intramolecular heavy atom effect (HAE) on the spectroscopic data and photophysical rate constant was analyzed and the incorporation of chlorine atoms to the carbazole moiety proved their ability to quench the fluorescence emission by spin-orbital coupling. The values of the HOMO and LUMO energy, the oscillator strength ( f ) and the lmaxðabsÞ associated to the electronic transitions, the heat of formation of the chlorocarbazoles and the corresponding radical cation (DHf andf ) and the lmaxðabsÞ associated to the electronic transitions, the heat of formation of the chlorocarbazoles and the corresponding radical cation (DHf andDHf and DHf ðRCÞ) and the adiabatic ionization potential (Ia) were also calculated by using the semiempirical PM3 method after HF/3-21G geometrical optimization, and were compared with the spectroscopic and photophysical data as well as with the one electron oxidation potential data (Ep=2). r 2002 Elsevier Science B.V. All rights reserved.Hf ðRCÞ) and the adiabatic ionization potential (Ia) were also calculated by using the semiempirical PM3 method after HF/3-21G geometrical optimization, and were compared with the spectroscopic and photophysical data as well as with the one electron oxidation potential data (Ep=2). r 2002 Elsevier Science B.V. All rights reserved.Ep=2). r 2002 Elsevier Science B.V. All rights reserved.