Nature of Si-H Interactions in a Series of Ruthenium Silazane Complexes Using Multinuclear Solid-State NMR and Neutron Diffraction

作者：Smart Katharine A; Grellier Mary^*; Coppel Yannick; Vendier Laure; Mason Sax A; Capelli Silvia C; Abinati Alberto; Montiel Palma Virginia; Munoz Hernandez Miguel A; Sabo Etienne Sylviane

来源：Inorganic Chemistry, 2014, 53(2): 1156-1165.

DOI：10.1021/ic4027199

Three new N-heterocyclic-silazane compounds, 1a-c, were prepared and employed as bidentate ligands to ruthenium, resulting in a series of [Ru(H){(kappa-Si,N-(SiMe2-N-heterocycle)}(3)] complexes (3a-c) featuring the same RuSi3H motif. Detailed structural characterization of the RuSi3H complexes with X-ray diffraction, and in the case of triazabicyclo complex [Ru(H){kappa-Si,N-(SiMe2)(C7H12N3)}(3)] (3a), neutron diffraction, enabled a reliable description of the molecular geometry. The hydride ligand of (3a) is located closer to two of the silicon atoms than it is to the third. Such a geometry differs from that of the previously reported complex [Ru(H){(kappa-Si,N-(SiMe2)N(SiMe2H)(C5H4N)}(3)] (3d), also characterized by neutron diffraction, where the hydride was found to be equidistant from all three silicon atoms. A DFT study revealed that the symmetric and less regular isomers are essentially degenerate. Information on the dynamics and on the Ru center dot center dot center dot H center dot center dot center dot Si interactions was gained from multinuclear solid-state (H-1 wPMLG, Si-29 CP MAS, and 2D H-1-Si-29 dipolar HETCOR experiments) and solution NMR studies. The corresponding intermediate complexes, [Ru{kappa-Si,N-(SiMe2-N-heterocycle)}(eta(4)-C8H12)(eta(3)-C8H11)] (2a-c), involving a single silazane ligand were isolated and characterized by multinuclear NMR and X-ray diffraction. Protonation of the RuSi3H complexes was also studied. Reaction of 3a with NH4PF6 gave rise to [Ru(H)(eta(2)-H -SiMe2)kappa-N-(C7H12N3){kappa-Si,N-(SiMe2)(C7H12N3)}(2)](+)[PF6](-)(4aPF(6)) which was isolated and characterized by NMR spectroscopy, X-ray crystallography, and DFT studies. The nature of the Si-H interactions in this silazane series was analyzed in detail.

• 出版日期2014-1-20