Excited-state properties of trans-1-(9-anthryl)-2-(4-R-phenyl)ethylenes with electron-donating and -accepting substituents [R = N(CH3)2, OCH3, CH3, Br, CN, and NO2

Abstract

The decay pathways of the lowest excited singlet state ( 1 t * ) of trans-1-(9-anthryl)-2-(4-R-phenyl)ethylenes (trans-R-StAs, where R=N(CH 3 ) 2 , OCH 3 , CH 3 , Br, CN, and NO 2 on the 4-position of the styryl) were studied in solution at room and low temperatures. Fluorescence lifetime (τ f ) and quantum yield (Φ f ) as well as the yield (Φ T ) and spectral and kinetic properties of the lowest triplet state were determined by steady-state and transient techniques. The solvent polarity has a large effect on the Stokes shift for (H 3 C) 2 N- and O 2 N-StA, the two derivatives with the strongest electron-donating and -accepting substituents