Synthesis and characterization of heterometallic Rh/Ru complexes supported by 1,2-dichalcogenolato-o-carborane ligands

The 16-electron half-sandwich complexes Cp∗Rh[E2C2(B10H10)] (E = S, 1a; Se, 1b) react with [Ru(COD)Cl2]x under different conditions to give different types of heterometallic complexes. When the reactions were carried out in THF for 24 h, the binuclear Rh/Ru complexes [Cp∗Rh(μ-Cl)2(COD)Ru][E2C2(B10H10)] (E = S, 2a; Se, 2b) bridged by two Cl atoms and the binuclear Rh/Rh complexes (Cp∗Rh)2[E2C2(B10H10)] (E = S, 3a; Se, 3b) with direct Rh–Rh bond can be isolated in moderate yields. [Ru(COD)Cl2] fragments in 2a and 2b have inserted into the Rh–E bond. If the [Ru(COD)Cl2]x was reacted with 1a in the presence of K2CO3 in methanol solution, the product [Cp∗Rh(COD)]Ru[S2C2(B10H10]] (4a), K[(μ-Cl)(μ-OCH3)Ru(COD)]4 (5a) and 3a were obtained. The B(3)–H activation in complex 4a was found. However, when the reaction between 1b and [Ru(COD)Cl2]x was carried out in excessive NaHCO3, the carborane cage opened products {Cp∗Rh[S2C2(B9H10)]}Ru(COD) (6b), {Cp∗Rh[S2C2(B9H9)]}Ru(COD)(OCH3) (7b) and 3b were obtained. All complexes were fully characterized by their IR, 1H NMR and elemental analyses. The molecular structures of 2a, 2b, 3b, 4a, 5a, and 7b have been determined by X-ray crystallography.