Picosecond transient absorption spectroscopy of trans-1-(9-anthryl)-2-(4-R-phenyl)ethylenes with electron-donating and -accepting substituents

The spectroscopic properties of the title compound styrylanthracene (StA) and its derivatives (R: NO2, CN, Br, Me, OMe and NMe2) were studied by picosecond time-resolved absorption techniques in solution at room temperature. The lifetime of the excited singlet state S1 varies with increasing the solvent polarity from 1–3 ns to ⩽100 ps for compounds with strong electron-donating (OMe and NMe2) and -accepting (CN and NO2) groups. The effect of polarity on the deactivation pathways of these push–pull polyenes is suggested to be due to an intramolecular charge transfer.