Structural studies of substituted hydrazine complexes. Part 2. Crystal and molecular structure of (η-cyclo-octa-1,5-diene)tris(NN-dimethylhydrazine)hydroruthenium(II) hexafluorophosphate

Abstract

The crystal and molecular structure of the title complex has been determined by X-ray diffraction methods from counter data. The colourless crystals, M= 535.6, are monoclinic with space group P2₁/n, a= 14.96(2), b= 16.34(2), c= 9.78(2)Å, β= 92.6(1)°, and Z= 4. The structure has been solved by the heavy-atom method and refined by least-squares to R 0.063 for 1 780 observed reflections (graphite-monochromatized Mo-K_α radiation). The co-ordination geometry of the cation is approximately octahedral with the six sites occupied by a bidentate cyclo-octa-1,5-diene ligand, a hydride ligand (unlocated), and a fac configuration of NH₂NMe₂ ligands, bonded to the ruthenium via NH₂ nitrogen atoms. The bond from ruthenium to the nitrogen atom trans to the hydride ligand [2.28(1) A] is significantly longer than those to the other two co-ordinated nitrogen atoms [mean 2.19(1)Å;]. The small N–Ru–N angles (82, 84, and 86°), short non-bonded distances between the NH₂ and NMe₂ nitrogen atoms (2.87, 2.89, and 2.93 Å), and the symmetrical arrangement of the hydrazine ligands are indicative of hydrogen bonding between these ligands.