Synthesis of rhodium(III)-pyridine complexes: an electrophoretic and chromatographic study

Abstract The synthetic methods for the preparation of rhodium(III)–pyridine complexes were examined using zone electrophoresis and thin-layer chromatography. Most syntheses produce a mixture of three to four complexes. Fresh solutions of commercial RhCl 3 · n H 2 O contain as many as ten electrophoretically different species. A yellow electrophoretically pure Rh(py) 3 Cl 3 (presumably the fac form) could be prepared, which in dilute acid converts into another neutral species, presumably the mer form. These could be separated by thin-layer chromatography on cellulose. The importance of examining the purity of monodentate complexes prepared by the usual synthetic methods is stressed.