Synthesis and characterization of hetero-binuclear Co–Rh complexes [Cp∗CoS2C2(B9H10)][Rh(COD)] and [Cp∗CoSe2C2(B10H10)][Rh(COD)]

Two hetero-binuclear complexes [Cp∗CoS2C2(B9H10)][Rh(COD)] (2a) and [Cp∗CoSe2C2(B10H10)][Rh(COD)] (2b) [Cp∗ = η5-pentamethylcyclopentadienyl, COD = cyclo-octa-1,5-diene (C8H12)] were synthesized by the reactions of half-sandwich complexes [Cp∗CoE2C2(B10H10)] [E = S (1a), Se (1b)] with low valent transition metal complexes [Rh(COD)(OEt)]2 and [Rh(COD)(OMe)]2. Although the reaction conditions are the same, the structures of two products for dithiolato carborane and diselenolato carborane are different. The cage of the carborane in 2a was opened; However, the carborane cage in 2b was intact. Complexes 2a and 2b have been fully characterized by 1H, 11B NMR and IR spectroscopy, as well as by elemental analyses. The molecular structures of 2a and 2b have been determined by single-crystal X-ray diffraction analyses and strong metal–metal interactions between cobalt and rhodium atoms (2.6260 Å (2a) and 2.7057 Å (2b)) are existent.