Synthesis, Characterization, Absorption Properties, and Electronic Structures of Paddlewheel-Type Dirhodium(II) Tetra-μ-(-naphthoate) Complexes: An Experimental and Theoretical Study.

The reactions of [Rh₂(O₂CCH₃)₄(OH₂)₂] with -naphthalenecarboxylic acids ( = 1: 1-HNC, = 2: 2-HNC) afford the dirhodium tetra-μ-(-naphthoate) complexes [Rh₂(1-NC)₄] () and [Rh₂(2-NC)₄] (), respectively. Single crystal X-ray diffraction analyses of [1(OCMe₂)₂] and [2(OCMe₂)₂], which were obtained by recrystallization from acetone (OCMe₂) solutions of and , reveal that the dirhodium cores are coordinated by four equatorially bridging naphthoate ligands and two axial OCMe₂ ligands. Density functional theory (DFT) calculation confirmed that (i) the single Rh⁻Rh bond is formed between the two Rh ions and (ii) the electronic structures between two Rh ions in and are best described as π⁴δ²σ²δ*²π*⁴ and δ²π⁴σ²δ*²π*⁴, respectively.