Structure-dependent switchover of reaction modes: A laser flash photolysis and magnetic field effect study

This work illustrates a switchover of reaction mode on account of steric effect in different types of media. We have observed that in polar organic medium, 2-methyl-1,4-naphthoquinone (menadione, MQ) undergoes electron transfer (ET) with different amines, e.g., triethylamine (TEA), N,N-dimethylaniline (DMA) and 4,4′-bis(dimethylamino)diphenylmethane (DMDPM), whereas in SDS micelles it abstracts hydrogen from DMA and DMDPM although ET persists with TEA. On the contrary, our previous reports indicate that the mode of interaction of 9,10-anthraquinone with DMA and DMDPM is predominantly ET in both these media. Here we have attempted to explain such anomalous behavior.