Substituent Control of the Reductive Nitrosylation of Wilkinson's Catalyst by Diazeniumdiolates

Diazeniumdiolates (RN(O)NO⁻, R=Et, Et₂N) react in an R‐dependent manner with Wilkinson's catalyst to give either a chelated square‐planar complex, Rh(η²‐O₂N₂Et)(PPh₃)₂, 1 , for R=Et, or with initial chelation followed by reductive nitrosylation to give Rh(NO)(PPh₃)₃, in the case of R=Et₂N. Methyl iodide oxidatively adds to 1 to give RhIMe(η²‐O₂N₂Et)(PPh₃)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.