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.