Step-by-step introduction of silazane moieties at ruthenium: Different extents of Ru-H-Si bond activation

摘要

The coordination of pyridine-2-amino(methyl)dimethylsilane ligands to ruthenium has afforded access to a family of novel complexes that display multicenter Ru-H-Si interactions according to the number of incorporated ligands. The new complexes Ru[κ-Si,N-(SiMe_2)N(Me)(C _5H_4N)](η4-C_8H 12)(η3-C_8H_(11)) (1), Ru _2(μ-H)_2(H)_2[κ-Si,N-(SiMe _2)N(Me)(C_5H_4N)]_4 (2), and Ru(H)[κ-Si,N-(SiMe_2)N(Me)(C_5H_4N)] _3 (3) were isolated and fully characterized. The complexes exhibit different degrees of Si-H activation: complete Si-H cleavage, secondary interactions between the atoms (SISHA), and η~2-Si-H coordination. Reversible protonation of 3 leading to the cationic complex [RuH{(η~2-H-SiMe_2)N(Me)κ-N-(C_5H _4N)}{κ-Si,N-(SiMe_2)N(Me)(C_5H _4N)}_2]~~+[BAr~F _4] - (5) was also demonstrated. The coordination modes in these systems were carefully studied with a combination of X-ray and neutron diffraction analysis, DFT geometry optimization, and multinuclear NMR spectroscopy.