Hydrogen bonding effects on coordinated sulfoxides and relative role of intra- and inter-molecular interactions determining the dmso orientation in [RR′NHOH][fac-RuCl3(dmso)3] compounds: a crystallographic and molecular mechanics study

Compounds with hydroxyl ammonium cations, [RR′NHOH][ fac -RuCl 3 (dmso–S) 3 ], with R=R′=H ( 1 ), R=Me, R′=H ( 2 ) and R=R′=Et ( 3 ), have been prepared and structurally characterized by X-ray analyses. The three compounds display chain-like structures, formed by hydrogen bonding between the hydroxyl ammonium cations and the chlorine and oxygen atoms of the ruthenium anion. H-bonding involving the dmso oxygen atoms causes a lengthening of the S–O bonds. The comparison of the solid state structures with results of Molecular Mechanics calculations show that the arrangement of the fac -dmso–S ligands is not determined by H-bonding or packing effects, but from intramolecular steric and electrostatic interactions. These give rise to hindered rotation about the Ru–S bonds.