Laser flash photolysis study of trans-styrylphenanthrene isomers and their exciplexes with amines

Abstract

The role of the lowest triplet state in the direct and charge-transfer-induced trans→cis photoisomerization of the five isomers of trans-n-styrylphenanthrene (t-n-StPh, with n=1, 2, 3, 4, and 9) has been investigated by the nanosecond laser flash photolysis technique. The influence of charge-transfer interactions and for heavy-atom effect on the intersystem-crossing quantum yields and triplet lifetimes (TT) has been studied. Triplet yields of t-n-StPh's have been estimated by the enhancing effect atoms. In the presence of N,N-diethylaniline (DEA) and tributylamine (TBA), the laser flash photolysis measurements have shown a T-T transient absorption with an exciplex character