Isolation of a Tetranuclear Intermediate Complex in the Synthesis of Paddlewheel‐Type Dirhodium Tetraacetate

Abstract

AbstractTo investigate the detailed mechanism of formation of the paddlewheel‐type dirhodium tetraacetate [Rh2(O2CCH3)4(L)2] ([1‐(L)2]; L = axial‐coordinated solvent ligand), we performed a step‐by‐step synthesis. The isolated red intermediate complex [Rh4(μ‐Cl)4(O2CCH3)4(L)4] ([2‐(L)4]) was characterized by means of single‐crystal X‐ray diffraction, 1H NMR spectroscopy, infrared spectroscopy, and elemental analysis. The crystal structure of [2‐(MeOH)4], which was crystallized from MeOH solution, has a unique twisted‐box Rh4(μ‐Cl)4 core coordinated by four μ‐carboxylato bridging ligands and four MeOH molecules as axially coordinated solvent molecules. The electronic structure and absorption properties of [2‐(MeOH)4] in MeOH were also carefully investigated both experimentally and theoretically.