Single-Crystal XRD Characterization, Physicochemical Properties and Catalytic Activity of Rhodium(III/IV) Coordination Compounds

Abstract

Two novel rhodium(III) and rhodium(IV) coordination compounds incorporating dipicolinate anion, 1,10-phenanthroline, and 2-phenylpyridine are presented. The crystal structure of the compounds was confirmed by single-crystal X-ray diffraction (XRD). Their physicochemical properties were investigated by potentiometric and conductometric titrations. Stability constants were determined using Hyperquad fitting analyses. In addition, the newly synthesized complexes were used as precatalysts for the polymerization of ethylene and the copolymerization of ethylene with α-olefins and methyl acrylate.Moderate catalytic activities of up to 3.13 x 10 5 gPE molRh -1 h -1 were achieved. The addition of comonomers reduces the catalytic activity but allows for control over the copolymer's microstructure and properties. These results establish clear structure-activity relationships in the (co)polymerization of olefins process.