Multinuclear Self-Assembly via a (p-Cymene)ruthenium Unit and an o-Carborane Selenolate Ligand

Treatment of o-carborane, n-butyllithium, selenium, and [(p-cymene)RuCl2]2 under argon leads to the complexes (p-cymene)Ru(Se2C2B10H10) (1), [(p-cymene)RuCl(Se−SeC2B10H11)][(p-cymene)Ru(Se2C2B10H10)] (2), [(p-cymene)Ru2(Se2C2B10H10)2][(p-cymene)Ru(Se2C2B10H9)] (3), and [(p-cymene)Ru(Se2C2B10H9) Ru(Se2C2B10H10)]2 (4). 2 contains a rhombic Ru2Se2 core and can be considered as an adduct of the two 16e half-sandwich monomers (p-cymene)Ru(Se2C2B10H10) (1) and (p-cymene)RuCl(Se−SeC2B10H11). In 3 three o-carborane-1,2-diselenolate ligands bridge the adjacent Ru atoms and one [Se2C2B10H9]3− unit is in a tridentate binding mode with a Ru−B bond. In 4, two identical dinuclear (p-cymene)Ru2(Se2C2B10H9)(Se2C2B10H10) subunits connect to each other through two Se atoms of two individual [Se2C2B10H10]2− ligands and a metal-induced B−H activation occurs as well. However, if the above reaction mixture is exposed to air, the unexpected product [(p-cymene)Ru]2(Se2C2B9H10)Ru2(Se2C2B10H10)3(μ-O) (5) can be isolated in moderate yield. It contains a novel Ru4Se8O core generated from three [Se2C2B10H10]2−, one nido-[Se2C2B9H10]3−, and one μ-oxo unit. Complexes 2−5 have been characterized by elemental analyses, mass and NMR spectra, and X-ray crystallography.