Weak M - H...H - C interactions observed in ruthenium and iridium complexes containing hydride, amine, and bulky phosphine ligands

Article abstract of DOI:10.1139/v97-055

New amineruthenium and amineiridium hydride derivatives have been synthesized and characterized with the objective of observing intramolecular MH...HN or MH...HO interactions. These include RuHCl(CO)(L)(PPr^j₃)₂ (1a, L = NH₂NH₂; 1b, L = NH₃) and IrCl₂(L)(H)(PCy₃)₂ (2a, L = SC(NH₂)₂; 2b, L = NH₃; 2c, L = NH₂NH₂; 2d, L = NH₂(CH₂)₃NH₂; 2e, L = NH₂OH). Instead, weak M - H...H - C van der Waals contacts have been detected in the solid state by X-ray analysis and in solution by NMR T₁ measurements and nOe techniques. Both X-ray crystal structure analysis and minimum T₁ measurements indicate that the H...H distances in the M - H...H - C interactions are ca. 2.0-2.2 A. The weak interactions might influence the course of deuteration of these complexes under D₂ gas. The crystal and molecular structure of IrCl₂(NH₃)(H)(PCy₃)₂ 2a has been determined by X-ray diffraction at 173 K: monoclinic, space group P2₁/n, a = 14.859(2) A, b = 18.579(3) A, c 7 18.548(3) A, β = 97.29(1)°, V = 5079.1(13) A³, Z = 4, full-matrix least-squares refinement on F² for 10 953 independent reflections; R[F² > 4σ(F²)] = 0.0283, wR(F²) = 0.0704.