Electron Paramagnetic Resonance and Electron Nuclear Double Resonance Studies of the Chemical Reactions of Diphenyldiazomethane and of Diphenylmethylene in Single 1,1-Diphenylethylene Crystals

Electron paramagnetic resonance and electron nuclear double resonance methods were used to investigate the rates and mechanisms of the chemical reactionsdiphenyldiazomethane→ lim hνdiphenylmethylene+N2,diphenylmethylene+1,1-diphenylethylene→ 1,1,2,2-tetraphenylcyclopropane, and diphenylmethylene+diphenyldiazomethane→ benzophenone azine. These reactions occurred in single crystal solutions of diphenyldiazomethane in 1,1-diphenylethylene during irradiation with visible and ultraviolet light or after termination of irradiation, without any general disruption of the structure. The crystal structure of these chemically reacting solutions was investigated by electron paramagnetic resonance spectroscopy, by electron nuclear double resonance spectroscopy, by x-ray diffraction, and by optical absorption spectroscopy. All of these methods and techniques nicely supplemented each other to give a very detailed picture of this single crystal chemically reacting system and of the mechanisms of the processes which were involved.