Effects of magnesium salts on photoinduced electron transfer reaction between ammonia, 2,5-dimethylhexa-2,4-diene, and 9-cyanophenanthrene

Mechanistic studies and product analyses were performed on the single electron transfer (SET) promoted photoamination reaction between 2,5-dimethylhexa-2,4-diene (1) and 9-cyanophenanthrene in order to gain a comprehensive understanding of the effects of additive metal salts. The product selectivity of this process was found to be dramatically increased by the addition of Mg2+ salts. An investigation involving the analyses of fluorescence and time-resolved absorption spectroscopic properties reveals that Mg2+ enhances the rate of the initial SET step and stabilizes the resulting radical ion pair in this photoreaction.