Dielectric dependence of magnetic field effect: A tool for identification of exciplex and triplex

The molecule, 4,4-bis(dimethylamino)diphenylmethane (DMDPM), having two pot ential donor sites is able to form both luminescent exciplex, (1:1) and tri plex (1:2) with photoexcited pyrene. (PY), which is inferred from the maxim ization of magnetic field effects at two different dielectric constants of the solvent media. The DMDPM molecule can be considered as two N,N-dimethyl aniline (DMA) molecules linked through a methylene chain. Therefore, electr on hopping is likely to occur from one DMA unit to the other through the in termediate > CH2 group, which is reflected in the B-1/2 measurements and is in agreement with Schulten's theory of intramolecular electron exchange. T he nature of charge transfer and electron hopping is substantiated with the oretical calculations highlighting relative orientations of PY and DMDPM.