The fluorescence of trans-stilbene is quenched by several secondary and tertiary amines. Quenching by tertiary amines in nonpolar solvents is accompanied by the appearance of exciplex fluorescence. The temperature dependence of fluorescence quenching by secondary and tertiary amines in polar and nonpolar solvents is indicative of reversible exciplex formation in all cases. Addition of the α C-H bond of tertiary amines to singlet stilbene occurs only in polar aprotic solvents. Electron transfer from the tertiary amine to stilbene apparently must precede proton transfer. The addition of the N-H bond of secondary amines to stilbene occurs in all aprotic solvents. The behavior of exciplexes formed from trans-stilbene with secondary and tertiary amines and conjugated dienes is compared.
ASJC Scopus subject areas
- Colloid and Surface Chemistry