Structural investigations on rhodium(III) complexes. Part II. Crystal structure of mer-trichlorobis-(o-dimethylaminophenyldimethylarsine)rhodium(III)

Abstract

The crystal structure of mer-trichlorobis-[(o-dimethylaminophenyl) dimethylarsine]rhodium(III) RhCl₃(nas)₂(nas =o-dimethylaminophenyldimethylarsine) has been determined from three-dimensional X-ray diffraction data and refined by least-squares calculations to R 0·095 for 1518 observed reflections. The crystals are ortho-rhombic, space group P2₁2₁2₁(D₂⁴), with Z= 4 in a unit cell of dimensions a= 14·00 ± 0·012, b= 15·723 ± 0·017, and c= 11·516 ± 0·012 Å. The structure consists of discrete molecules. The co-ordination octahedron around the rhodium atom consists of three chlorine atoms, two ligand arsenic atoms in trans-positions and one ligand nitrogen atom. The nitrogen atom of the second ligand is not co-ordinated. All the Cl–Rh distances lie in the range 2·32–2·35 Å. The two Rh–As distances are 2·342 Å for the chelating ligand, and 2·529 Å for the monodentate ligand. The structures of this molecule, and of related rhodium(III) complexes, are discussed with reference to the vibrational spectra of the molecules in the metal–ligand stretching region.