PHOTOPHYSICAL PROPERTIES OF STYRYL DERIVATIVES OF AMINOBENZOXAZINONES

The spectra, fluorescence quantum yields, and lifetimes of styryl derivatives of (dimethylamino)bezoxazinone in various solvents are reported. The results show that the main chromophore is the aminobenzoxazinone moiety and the para-substituted styryl moiety is a substituent as a whole. Therefore, these compounds do not behave as stilbene derivatives in spite of analogy in chemical structure. The effect of the substituent in the para position of the styryl moiety has been carefully examined with the help of quantum mechanical calculations by PPP and CNDO/S methods. The possibilities of internal rotation leading in particular to twisted intramolecular charge transfer (TICT) states are discussed.