Coordination chemistry of the 2-pyridyldiphosphine ligands, (py)(2)P(CH(CH2)(3)CH)P(py)(2) and (py)(2)P(CH2)(2)P(py)(2) (py=2-pyridyl), with platinum(II) and ruthenium(II). Ruthenium-catalyzed hydrogenation of imines

{The synthesis and characterization of a range of Pt(II) and Ru(II) complexes containing the new 2-pyridyldi-phosphine ligand, d(py)pcp = (py)(2)P(CH(CH2)(3)CH)P(py)(2) (made as a racemate) and the previously reported d(py)pe = (py)(2)P(CH2)(2)P(py)(2) are given (py =2-pyridyl). The Pt complexes made were cis-PtX2(d(py)pcp) (X = Cl (1), I (2)), cis-PtX2(d(py)pe) (X = Cl (3), I (4)), [Pt(d(py)pcp)(2)][PF6](2) (5), and [Pt(d(py)pe)(2)][PF6](2) (6); these all contain P,P-bonded diphosphine ligand, as evidenced by P-31 NMR data and by crystallographic data in the case of 2 and 3. The X-ray structure of d(py)pe is also reported. The complexes RuX2(P,P,N-d(py)pcp)(PPh3) have cis-halogens and a P,P,N-bonding mode of the pyridyldiphosphine (which incorporates a four-membered P,N-chelate ring) with either a mer-arrangement (in 7a