Exciplex Photophysics. 7. Steric Effects in Exciplex Photophysics

Article abstract of DOI:10.1021/j100226a019

The influence of steric interference with sandwich-type exciplex formation has been investigated by using mono- and di-tert-butylsubstitution of N,N'-dimethylaniline (DMA).Pyrene was the electron acceptor and studies were carried out with both steady-state and fluorescence lifetime techniques in hexane and tetrahydrofuran (THF).All the rate constants of the classical exciplex mechanism were determined along with temperature coefficients.It was found that the most significant effect of tert-butyl substitution was a substantial decrease in the process (AQ)^* -> A^* + Q.Solvent effects, exciplex thermodynamics, and activation parameters are discussed for the unsubstituted and tert-butyl-substituted systems.