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

Abstract

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)₂N(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]Cl₂. 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.