Palladium(II) and platinum(II) complexes formed from C6H4-1,3-(CH2PCy2)2: crystal and molecular structures of [PdX{C6H3-2,6-(CH2PCy2)2}], X = Cl and Br

The reaction of C6H4-1,3-(CH2PCy2)2 (Cy = cyclohexyl) with [PdCl2(NCPh)2] gave mainly [PdCl2C6H4-1,3-(CH2PCy2)2]n which was converted into [PdClC6H3-2,6-(CH2PCy2)2] on prolonged reflux, whereas C6H4-1,3-(CH2PCy2)2 reacted with [PdBr2(PPh3)2] to give mainly [PdBrC6H3-2,6-(CH2PCy2)2]. Only [PtCl2C6H4-1,3-(CH2PCy2)2]n was formed in the analogous reaction with [PtCl2(NCPh)2]. X-ray analysis showed that [PdClC6H3-2,6-(CH2PCy2)2] and [PdBrC6H3-2,6-(CH2PCy2)2] are isostructural. Both molecules display a conformation of the terdentate PCP ligand that is different from that recently reported for several related molecules. It is concluded that the conformation adopted by C6H3-2,6-(CH2PR2)2 ligands appears to be dominated by the steric demand of the phosphorus substituents.