Aminosilanes as two-electron donors: A technological application of radical cation chemistry

Aminosilanes possess the appropriate structural features for use as two-electron sensitizers in silver halide photography. Here, we describe studies of the nucleophile-assisted cleavage reactions of the C - Si bonds in their radical cations. Water is identified as a useful nucleophile. It is found that the kinetics of these reactions are best described by taking into account a radical cation - water complex. The cleavage reactions are also controlled by steric effects at silicon and by the proximity of a carboxylate group that can modify the nucleophilicity of the water. Cleavage forms an α-amino radical that can donate a second electron to 9,10-dicyanoanthracene as a solution-phase electron acceptor.