Step-by-Step Introduction of Silazane Moieties at Ruthenium: Different Extents of Ru–H–Si Bond Activation

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-(SiMe2)­N­(Me)­(C5H4N)]­(η4-C8H12)­(η3-C8H11) (1), Ru2(μ-H)2(H)2[κ-Si,N-(SiMe2)­N­(Me)­(C5H4N)]4 (2), and Ru­(H)­[κ-Si,N-(SiMe2)­N­(Me)­(C5H4N)]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 η2-Si–H coordination. Reversible protonation of 3 leading to the cationic complex [RuH­{(η2-H-SiMe2)­N­(Me)­κ-N-(C5H4N)}­{κ-Si,N-(SiMe2)­N­(Me)­(C5H4N)}2]+[BArF4]− (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.