Tetramethyl-/j-phenylenediamine

Replacing the weak electron donor DMA with a 7V,7V,A, Ar -tetramethyl-/j-phenylenediamine (TMPD) donor increases the energy gap between the fullerene singlet excited state and the charge-separated state [323]. As a consequence of a more exergonic electron transfer, the Ceo-TMPD dyad (8) gives rise to fast intramolecular charge separation, irrespective of the solvent polarity (i.e., non-polar methylcyclohexane and polar benzonitrile) [323]. 

Willems also showed, in the same article, that some compounds that formed stable radicals would also catalyze silver bleaching by persulfate. He suggested that these compounds acted as electron transfer agents, performing as a shuttle for electrons from the silver to the persulfate thus a superadditive mechanism, similar to that seen in development, could operate. Kobayashi et al. [141] observed a similar effect with Af,7V,Af, 7V -tetramethyl-/j-phenylenediamine but also showed that this compound was destroyed by the action of persulfate, and benzoquinone was formed. It was this quinone that acted as the electron transfer agent in aged solutions. 

Two papers have appeared on the photoionization of A,yV,iV, jV -tetramethyl-/j-phenylenediamine (TMPD) in various solvents. Emission and absorption... 

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