Coordination chemistry of inversely polarized phosphaalkenes toward group 10 metal centers

A series of palladium and platinum complexes containing inversely polarized phosphaalkenes (Me2N)(R)C=PR' (R = H, R' = Mes*, 2; R = Me, R' = Mes*, 3; R = H, R' = Mes, 4), exhibiting different steric and electronic environments, have been synthesized. Ligand 2 coordinates in eta(1)-P fashion to either palladium (PdCl2(eta(-)P)2, 5) or platinum (cis-Pt(Cl)(2)(eta(1)-P)(2), 6; trans-Pt(Cl)(2)(eta(1)-P)(2), 7). The equimolar reaction of 3 with Pd(COD)Cl-2 afforded a mixture in 3/1 ratio of cyclopalladated dimeric complexes [PdCl(kappa(2)-P,C-CH2N(Me)CH=PMes*)](2), 9 (cis isomer) and 9' (trans isomer). The latter was characterized by X-ray diffraction. The less hindered ligand 4 acts as bridging phosphido-like ligand with both palladium (mu-P-[PdCl2(MesP=CH(NMe2))](2), 11) and platinium (mu-P-[PtCl2(MesP=CH(NMe2))](2), 12). In the platinum case, the reaction of two or more equivalents of the ligand 4 gave a mixture of the complex containing 2 ligands/Pt and the cationic complex with 3 ligands/Pt, 13. This complex was isolated from the reaction of 3.5 equiv of 4 with the Pt precursor.