Structural investigations on rhodium(III) complexes. Part I. Crystal structure of trichlorobis-(o-methoxyphenyldimethylarsine)rhodium(III)

Abstract

The crystal structure of trichlorobis-(o-methoxyphenyldimethylarsine)rhodium(III), RhCl₃ oas₂(oas =o-methoxyphenyldimethylarsine) has been determined by three-dimensional X-ray diffraction techniques and refined by least-squares calculations to R 0·10 for 1401 observed reflexions. The crystals are orthorhombic, space group P2₁2₁2₁, with Z= 4, and a= 9·077 ± 0·012, b= 15·218 ± 0·03, and c= 16·954 ± 0·03 Å. The structure consists of discrete molecules. A distorted octahedral arrangement around the rhodium atom is realized by three mutually cis chlorine atoms, two mutually cis arsenic atom, and one oxygen atom trans to the arsenic atom of the other ligand, the oxygen atom of which is not co-ordinated. All the Cl–Rh and As–Rh distances lie in the range 2·33 to 2·39 Å. The O–Rh bond-length is 2·24 Å. l.r. spectra in the 350 cm.^–1 region indicate that the longest Rh–Cl bond is broken when the complex is treated with silver nitrate in methanol to give the trans-octahedral product [RhCl₂ oas₂]Cl.