Stabilization of dichalcogenide ligands in the coordination sphere of a ruthenium system

The synthesis, structure and electronic properties of tetraruthenium dichalcogenide complexes displaying the exclusive coordination mode of dichalcogenide ligands have been discussed. The reactions of Li[BH 2 E 3 ] (E = S or Se) with [ClRu(μ-Cl)( p -cymene)] 2 ( p -cymene = η 6 -{ p -C 6 H 4 ( i Pr)Me}) at room temperature yielded tetrametallic dichalcogenide complexes [{Ru 2 Cl 2 ( p -cymene) 2 } 2 (μ 4 ,η 2 -E 2 )], 1-2 (E = S (1) and Se (2)). The solid-state X-ray structure of 1 shows that two {( p -cymene)RuCl} 2 moieties are bridged by a S-S bond. In addition to 2, the reaction of Li[BH 2 Se 3 ] with [ClRu(μ-Cl)( p -cymene)] 2 also yielded a mononuclear tris-homocubane analogue [Ru( p -cymene){Se 7 (BH) 3 }] (3) which is an analogue of 1,3,3-tris-homocubane and possesses D 3 symmetry. In order to isolate the Cp* analogue of 1, the reaction of [Cp*Ru(μ-Cl)Cl] 2 with Li[BH 2 S 3 ] was carried out, which led to the formation of bis/tris-homocubane derivatives [(Cp*Ru) 2 {μ-S n (BH) 2 }] ( n = 7 (4) and 6 (5)) along with the formation of ruthenium disulfide complexes [(RuCp*) 2 (μ,η 2 :η 2 -S 2 )(μ,η 1 :η 1 -S 2 )] and [(RuCp*) 2 (μ-SBHS-κ 1 B:κ 2 S:κ 2 S)(μ,η 1 :η 1 -S 2 )]. Complexes 1-5 have been characterized by multi-nuclear NMR, IR, UV-vis spectroscopy, and mass spectrometry and their molecular formulations (except 2) have been determined by single crystal X-ray crystallography. Furthermore, DFT calculations were performed that rationalize the stabilization of the dichalcogenide units (E 2 2- ) by the tetrametallic systems in 1-2.