The two-coordinate palladium bis-isocyanide complex, Pd(CNArDipp2)2 (ArDipp2 = 2,6-(2,6-(i-Pr)2C6H3)2C6H3), has been shown to react with a host of small molecule substrates and function as an efficient pre-catalyst for carbon-element cross-coupling reactions. In this presentation, synthetic, structural and mechanistic details are disclosed for the reaction between Pd(CNArDipp2)2 and nitrosoarene compounds. Treatment of Pd(CNArDipp2)2 with 2.0 equivalents of nitrosobenzene (PhNO) has been shown to generate the bis-nitrosoarene complex Pd(k1-N-PhNO)2(CNArDipp2)2, which possesses two anti-ferromagnetically coupled nitroxide radicals in the solid state. In solution, Pd(k1-N-PhNO)2(CNArDipp2)2 is in equilibrium with free nitrosobenzene and the h2-mono-nitrosobenzene complex, (h2-N,O-PhNO)Pd(CNArMes2)2. The interconversion between mono- and bis-nitrosobenzene complexes is mediated by multinuclear palladium intermediates generated by isocyanide dissociation. The isolation of these intermediates is presented. In addition, structural and spectroscopic details for a series of bisnitroxide-radical palladium complexes are presented and show that the extent of N-O bond reduction can be modulated by substituent changes on the nitrosoarene ring. For comparative purposes, the synthesis of the bis-isocyanide platinum(0) complex, Pt(CNArDipp2)2, is described and its reaction chemistry toward nitrosoarenes described. A major contrast between these systems is that full N-O bond cleavage and oxygen-atom transfer chemistry is observed exclusively in the case of Pt.

Nitrosoarene N-O bond activation by group 10 isocyanide complexes

245th National Meeting (2013)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.