Rhodium complexation with phosphoryl-containing calix[4]resorcine

Abstract

Complexation of rhodium compounds with phosphoryl-containing calix[4]resorcine in ethanol and acetone has been considered. The structure and properties of the synthesized complexes have been studied by IR and Raman spectroscopy, ¹H and ³¹P NMR, EPR, UV-Vis spectroscopy, and TG/DSC. The effect of the solvent nature and conformation of a macrocyclic ligand on the structure of the resulting complexes has been observed. It has been demonstrated that one of the key factors responsible for complexation in EtOH is self-association of the ligand without the participation of the solvent. Complex formation in acetone is determined by its high ionizing ability. In diamagnetic complexes, the macrocyclic ligand is coordinated to the central atom through the phosphoryl oxygen atoms. For triaquatrichlororhodium in an aprotic medium, coordination occurs through the oxygen atoms of resorcinol moieties, which is accompanied by the formation of resorcinol radical anion and conversion of the diethoxyphosphorylaryl groups into ethoxyhydroxyphosphorylaryl moieties.