Possible role of electron donor–acceptor complexes in chemical reactions: kinetic and spectroscopic studies
Kinetics and energetics of electron-transfer reactions of a few electron acceptors with NNN′N′-tetramethyl-p-phenylenediamine and other donors are reported. The kinetics are markedly affected by the solvent polarity and the acceptor strength. Solvent effects on the kinetics of the reaction between NN-dimethylaniline and tetracyanoethylene have been investigated in detail; the rate of formation of the tetracyanoethane derivative (which is the reaction intermediate), as well as of its subsequent reaction to yield NN-dimethyl-4-tricyanovinylaniline, are found to be equally solvent-sensitive. Reactions of a few substituted anilines with chloranil have been studied and the rate data are markedly dependent on the donor strength. Solvent effects on the reaction of aniline with chloranil are found to be appreciable.