Routes to dicationic ruthenium(II) nitrile complexes containing chelating diphosphine ligands: X-ray analyses of Ru(dppb)(MeCN)42+ 2PF6−(dppb = Ph2P(CH2)4PPh2) and trans-RuCl2(MeCN)4

Abstract

Routes to the Ru(PP)(RCN)42+ 2PF6− complexes (PP = Ph2P(CH2)4PPh2, dppb; R = Me, Ph) from the Ru(II) precursors Ru2Cl4(PP)2, and Ru2Cl4(PP)(PPh3) have been established. The X-ray crystal structure of the dppb-MeCN derivative (3) is described, and the steric effect of the diphosphine ligand is examined by comparison with the crystal structure of trans-RuCl2(MeCN)4 (5), which is also presented. Crystals of 3 are triclinic, a = 13.845(3), b = 14.419(2), c = 12.984(3) Å, α = 108.75(2)°, β = 116.40(1)°, γ = 68.58(1)°, and Z = 2, space group [Formula: see text] and those of 5 are orthorhombic, a = 13.058(2), b = 11.790(2), c = 8.562(1) Å, and Z = 4, space group Pbca. The structures were solved by the Patterson method and refined by full-matrix least-squares procedures to R = 0.039 and 0.024 (Rw = 0.046 and 0.028) for 9973 and 1131 reflections with I ≥ 3σ(I), respectively. Crystallographic and infrared data suggest that the nitrile ligands function solely as σ-donors in these ruthenium(II) complexes. Keywords: ruthenium, nitriles, diphosphine ligands.