| Abstract | The absorption and fluorescence spectra, fluorescence quantum yields and lifetimes of 3-cyano-4-furyl-6-phenyl-2-(9-anthralylidene)-
pyridine (FPAP) in various solvents are reported. The results show that the quantum yield of the fluorescence (f ) of FPAP is high
and decreased with increasing solvent polarity. The fluorescence decay time is almost single exponential, independent of the excitation
wavelength and its value decreases upon increasing the solvent polarity. The radiative rate constant (kr ), however, shows a maximum value
for solvents of intermediate polarity, e.g. in CHCl3 a value of 2:1 108 s?1 is attained. However, knr value increases with increasing
solvent polarity. The bathochromic shift of the emission spectra and the resulting increase in the excited state dipole moment indicate
the charge transfer (CT) character of the emitting singlet state of FPAP. The relatively large values of kr and the corresponding transition
dipole moment (Mf ) indicate the absence of a twist intramolecular charge transfer in the fluorescent states. © 2000 Elsevier Science B.V.
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