Photolytic or Oxidative Fragmentation of Trityl Diazeniumdiolate (ONCPh): Evidence for Both C-N and N-N Bond Cleavage.

Exposure of [K(18-crown-6)(THF)][CPh] (THF = tetrahydrofuran; Ph = phenyl) to an atmosphere of nitric oxide (NO) cleanly generates [K(18-crown-6)][ONCPh] () in excellent yields. A subsequent reaction of [ZnCl(THF)] with 3 equiv of affords the -diazeniumdiolate complex [K(18-crown-6)][Zn(ONCPh)] (). Both and were characterized by H and C{H} NMR spectroscopy, and their structures were confirmed by X-ray crystallography. Photolysis of using 371 nm light resulted in the formation of three trityl-containing products, namely, PhCH, 9-phenylfluorene, and PhCN(H)OCPh (). In addition, we detected nitrous oxide (NO), as well as small amounts of NO in the reaction mixture. In contrast, oxidation of with 1.2 equiv of [Ag(MeCN)][PF] resulted in the formation of O(CPh) as the major trityl-containing product; NO was also detected in the reaction mixture, but NO was not apparently formed in this case. The observation of these fragmentation products indicates that the [ONCPh] ligand is susceptible to both C-N bond and N-N bond cleavage. Moreover, the different product distributions suggest that [ONCPh] is susceptible to different modes of fragmentation.