Chelate Structure of a Dirhodium–Amino Acid Complex Identified by Chiroptical and NMR Spectroscopy

Abstract

AbstractDinuclear rhodium complexes have attracted considerable attention as a result of their chemical and biological reactivity. We report herein the synthesis and structural elucidation by combined spectroscopic methods of a new rhodium complex containing N‐methyl‐D‐phenylalaninate (NMfO–) as a chiral ligand. It has been demonstrated that the structure of the chiral complex formed in water is independent of the ligand/metal molar ratio, the type of solvent, and reaction time, as shown by HPLC and ESI‐MS analyses. The steric structure of the isolated and identified [Rh2(OAc)2(OfMN)2] complex was determined by chiroptical (VCD, ECD) and NMR spectroscopy supported by DFT calculations. By this combined analysis, our studies have shown that the complex formed has two chiral ligands chelated through the O and N atoms of their carboxylate and sec‐amino groups, respectively, in the vicinity of the two bridging acetate ligands.