Photophysical properties of an asymmetrical 2,5-diarylidene-cyclopentanone dye possessing electron donor and acceptor substituents
作者:Christopher A. Zoto、Robert E. Connors
DOI:10.1016/j.molstruc.2010.08.016
日期:2010.10
Spectroscopic and photophysical properties have been measured in a variety of solvents for (2E,5E)-2-(p-cyanobenzylidene)-5-(p-dimethylaminobenzylidene)-cyclopentanone (I), an asymmetrically substituted 2,5-diarylidene-cyclopentanone known to have potential for applications utilizing two-photon absorption (TPA). Compound I was synthesized by a simple procedure utilizing DIMCARB catalyst. Absorption and fluorescence maxima have been correlated with the E-T(30) solvent polarity scale. Theoretical TD-DFT calculations and Lippert-Mataga analysis demonstrate the internal charge transfer (ICT) nature of the S-0 -> S-1 excitation. Radiative and nonradiative decay constants have been determined from fluorescence quantum yields and lifetimes. Substantial variation with solvent in the rate of nonradiative decay is interpreted in terms of a competition between internal conversion and intersystem crossing. (C) 2010 Elsevier B.V. All rights reserved.