resulted in nearly quantitative azine formation, decomposition of an equimolar mixture of these two diazirines produced the carbene dimer from this reactant combination without azine. The mixed carbene dimer was proposed to have resulted from nucleophilic attack of 1- phenyldiazoethane, presumed to have been formed from 3-methyl-3-phenyl-diazirine, on chlorophenylcarbene (eq