Substituent control of the reductive nitrosylation of Wilkinson's catalystby diazeniumdiolates

Diazeniumdiolates (RN(O)NO-, R = Et, Et2N) react in an R-dependent manner w ith Wilkinson's catalyst to give either a chelated square-planar complex, R h(eta (O2N2Et)-O-2)(PPh3)(2), 1, for R = Et, or with initial chelation foll owed by reductive nitrosylation to give Rh(NO)(PPh3)(3), in the case of R = Et2N. Methyl iodide oxidatively adds to 1 to give RhIMe(eta (2)-O2N2Et)(PP h3)(2), 2, as a pair of isomers a, major, and b, minor. Both 1 and 2a have been structurally characterized by single-crystal X-ray diffraction.