Synthesis and ligand exchange reactions of P2Pd(II) and P2Pt(II) salicylaldimates

Reaction of (dppe)MCl2 (dppe = 1,2-bis(diphenylphosphino)ethane) with 2-(N-phenyliminomethyl)phenol leads to air-stable (dppe)M(NO) chelates (M = Pd, 1a; M = Pt, 1b). The N-4-methylphenyl derivative of la has been characterized by X-ray analysis. The NO ligands are kinetically labile and exchange occurs in solution in the presence of other salicylaldimines. In the presence of anilines, a metal-mediated imine exchange process occurs. Hammett analysis reveals that the platinum complexes are sensitive to the electronics at N but not at O. Electron donating groups on the N-aryl ring stabilize the metal complex.