Synthesis and co-ordination chemistry of a novel multifunctional bis-phosphine containing a P-N-Si-N-P backbone

A novel multifunctionalised bidentate phosphine ligand containing the highly unusual P-N-Si-N-P backbone has been synthesized and its co-ordination chemistry studied. The ligand Ph2PN(C5H4N-2)Si(Me)(2)N(C5H4N-2)PPh2, which was characterised crystallographically, forms cis-P,P chelate complexes with platinum or palladium. The complexes MLCl2 (M=Pt or Pd) readily hydrolyse under recrystallisation conditions to give chelate complexes [Pt(Ph2PNHC5H4N-2-P,N)(2)]Cl-2. The crystal structure of the platinum complex shows both P,N ligands to chelate to the metal, in contrast to the crystal structure reported previously [Pt(Ph2PNHC5H4N-2-P,N)(Ph2PNHC5H4N-2-P)Cl]Cl. The dimethyl platinum complex PtLMe2 is considerably more stable to hydrolysis, and it was therefore possible to characterise the six membered PtPNSiNP ring system by X-ray crystallography. In addition, evidence is also presented that the ligand and its complexes will react with other phosphorus electrophiles (with N-Si bond cleavage) to generate new compounds.