Diazoalkane cation radical

Under these conditions, the primary reactions after the formation of the diazoalkane cation radical can be studied. First-order kinetics were found. The rates are independent of pyridine and methanol and there is practically no deuterium isotope effect in tetradeuterated methanol. The solvent isotope effect (CD3CN and CD3OD and its mixtures) is minimal (e.g., kcH oa/f CD OD = 1-02). These results indicate a simple unimolecular dissociation of the CN bond, forming the dinitrogen molecule and the carbene cation radical. 

In an earlier review (Zollinger, 1994, Chapt. 8) we explained that the dediazoniation of aromatic diazonium ions to aryl cations and dinitrogen, or to aryl radicals and dinitrogen in the presence of suitable electron donors, is based primarily on the high stability of N2. Analogous aliphatic diazonium ions show similar behavior, but the existence of diazenides (R —Nf) and diazoalkanes also opens the possibility of generating carbanions, e.g., in the Wolff-Kishner reduction and related reactions (see the classic book of Cram, 1965, and the monographs of Staley, 1985, and Buncel and Durst, 1980-1987), and carbenes (see Chapt. 8 of this book). 

Bethell and coworkers have also investigated the oxidation of diazoalkanes. The initial step in the oxidation reaction is the reversible formation of the radical cation, Ph2C— which forms when the diazodiphenylmethane reacts with either copper(II) perchlorate or the stable radical cation salt, tris-(/ -bromophenyl)ammoniumyl perchlorate in acetonitrile (equation 29). 

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