The silver oxide oxidations of a number of oximes in benzene solution have been examined. The reaction probably involves the intermediate formation of iminoxy radicals. Rather complex mixtures of products are generally produced because of the instability of some of the initially formed iminoxy radical dimers. Iminoxy radicals can dimerize by N-N, N-O, and O-C coupling. The kinetics and rate constants for the decay of a wide variety of photochemically generated iminoxy radicals have been measured by epr spectroscopy. Under the conditions of the decay experiments the radicals are in equilibrium with "unstable" dimers. For unhindered dialkyliminoxy radicals the equilibrium is rapidly established and lies in favor of the dimers. Decay is first order. For the majority of diaryliminoxy, alkylaryliminoxy, and hindered dialkyliminoxy radicals the equilibrium favors the radicals or else is only slowly established and decay is second order. A unified reaction scheme is proposed but in view of the complexities of the iminoxy radical self-reactions the precise interpretation of the measured decay rate constants and activation parameters is uncertain.
Journal of the American Chemical Society94, no. 20 (1972): 7040–7049.