Single Electron Transfer to Diazomethane-Borane Adducts Prompts C-H Bond Activations.

While (Ph CN )B(C F ) is unstable, single electron transfer from Cp* Co affords the isolation of stable products [Cp* Co][Ph CNNHB(C F ) ] 1 and [Cp*Co(C Me CH B(C F ) )] 2. The analogous combination of Ph CN and BPh showed no evidence of adduct formation and yet single electron transfer from Cp* Cr affords the species [Cp* Cr][PhC(C H )NNBPh ] 3 and [Cp* Cr][Ph CNNHBPh ] 4. Computations showed both reactions proceed via transient radical anions of the diphenyldiazomethane-borane adducts to effect C-H bond activations.