Structural studies of substituted hydrazine complexes. Part 3. Crystal and molecular structure of dichlorobis(η-cyclo-octa-1,5-diene)-(NN-dimethylhydrazine)dihydridodiruthenium, an asymmetric triply bridged dimer containing a bidentate bridging NN-dimethylhydrazine ligand

Abstract

Crystals of the title complex are monoclinic, space group P2₁/c, with unit-cell dimensions a= 17.99(2), b= 7.46(2), c= 20.91(2)Å, and β= 133.8(1)°. A final R of 0.073 for 1 487 observed reflections has been obtained. The molecule is a highly distorted dimer with the two ruthenium atoms bridged by H^–, Cl^–, and NH₂NMe₂ ligands. Terminal chloride and hydride ligands are situated trans to, respectively, the bridging H^– and Cl^– ligands, and an η-cyclo-octa-1,5-diene is co-ordinated to each ruthenium atom. The methyl-substituted nitrogen is bonded to the ruthenium which carries the terminal H^– ligand. A unique structural feature is the bidentate bridging NH₂NMe₂ ligand: Ru–NH₂ 2.12, Ru–NMe₂ 2.24, and N–N 1.51 Å; Ru–NH₂–N 115 and Ru–NMe₂–N 103°. The Ru⋯Ru distance (2.91 Å) indicates the presence of a metal–metal bond of order one.