Expanding the family of heterobimetallic Bi–Rh paddlewheel carboxylate complexes via equatorial carboxylate exchange†
Abstract
Five novel homoleptic heterobimetallic bismuth(II)–rhodium(II) carboxylate complexes—BiRh(TPA)4 (1), BiRh(but)4 (2), BiRh(piv)4 (3), BiRh(esp)2 (4), and BiRh(OAc)4 (5)—were synthesized in good yields by equatorial ligand substitution starting from BiRh(TFA)4 (TPA = triphenylacetate, but = butyrate, piv = pivalate, esp = α,α,α′,α′-tetramethyl-1,3-benzenedipropionate, OAc = acetate, and TFA = trifluoroacetate). We report here 1H and 13C{1H} NMR spectra and cyclic voltammograms for complexes 1–4, and IR spectra for all complexes. Irreversible redox waves appear between −1.4 to −1.5 V for [BiRh]3+/4+ couples and 1.3 to 1.5 V vs. Fc/Fc+ for [BiRh]4+/5+ couples for complexes 1–4 indicating a wide range of stability for the compounds. The X-ray crystal structure of 1 reveals a Bi–Rh distance of 2.53 Å.