Trimethyl-palladium(IV) and -platinum(IV) complexes containing phosphine donor ligands, inchuding studies of 1,5,9-triethyl-1,5,9-triphosphacyclodecane and X-ray structural studies of palladium(II) and palladium(IV) complexes

摘要

Dimethyl(2,2'-bipyrine)palladium(II) reacted with methyl triflate (CF_3SO_3Me) at -60 deg C to form a palladium(IV) complex which reacted with a range of monodentate phosphines [PPh_3, PMePh_2, PMe_2Ph, P(OMe)_3], 1,2-bis(diethylphosphino)ethane (depe), or syn,syn-1,5,9-triethyl-1,5,9-triphosphacyclodecane (syn,syn-Et_3[12]aneP_3) to form complexes containing octahedral palladium(IV) centres fac-[PdMe_3(2,2'-bipy)(L)]~+ 1-5, 11-13. The ligand depe bridges between palladium(IV) centres in a binuclear complex (11), the triphosphine forms both mononuclear (13) and binuclear species (12), and representative complexes of other bidentate nitrogen donor ligands have also been prepared, [PdMe_3(N-N)[PMe_2Ph][O_3SCF_3][N-N = 1,10-phenanthroline (phen) 6 or N,N,N',N'-tetramethylethylene-diamine (tmen) 7]. The first structural analysis of an organopalladium(IV) phosphine complex is reported, and octahedral 6 and platinum(IV) complexes [PtMe_3(2,2'-bipy)(L)][O_3SCF_3] {L = PPh_3 8, PMePh_2 9 or PMe_2Ph 10} have been isolated. All of the palladium(IV) complexes reductively eliminate ethane on decomposition to form palladium(II) species, where the monodentate phosphines form [PdMe(N-N)(L)]~+ 1a-7a; a structural analysis of square-planar [PdMe_3(2,2'-bipy)(PMe_2Ph)][O_3SCF_3] 3a is reported. the stability of palladium(IV) complexes decreases in the order PMe_2Ph > PmePh_2 > PPh_3, and for complexes of PMe_2Ph there is a stability order phen > 2,2'-bipy > tmen for [PdMe_3(bidentate ligand)(PMe_2Ph)]]~+.