EXCIPLEX EMISSION FOR HYDROCARBON-DIMETHYLANILINE SYSTEMS IN HYDROXYLIC SOLVENTS

Exciplex emission from pyrene-dimethylaniline (DMA) and anthracene-DMA systems appears at a much lower wavelenght in n-propanol (ε{lunate} = 20.1) than in acetone (ε{lunate} = 20.7). For all primary alcohols the exciplex emission appears at about the same position irrespective of the dielectric constants of the alcohols. However, the alcohols strongly quenched the exciplex emission in n-heptane and this quenching followed the Stern-Volmer relation. The quenching constants were found to follow the order primary > secondary > tertiary. These findings have been attributed to the stabilization of the non-bonding electrons at the nitrogen atom in DMA through hydrogen bonding with the alcohols. © 1979.