Chlorosilanes and 3,5‐Dimethylpyrazole: Multinuclear Complexes, Acetonitrile Insertion and 29Si NMR Chemical‐Shift Anisotropy Studies

The multinuclear silicon complexes [{H2ClSi(-pz*)2}2SiH2] (1) and [Cl2Si(-pzRR)2SiCl2] (2, R = Me; 3, R = Ph) were formed by the reaction of dichlorosilane (for 1) or hexachlorodisilane with 1-trimethylsilyl-3,5-dimethylpyrazole (for 1 and 2) and the 3,5-diphenyl analogue (for 3). The reaction of trichlorosilane with 3,5-dimethylpyrazole (Hpz*) in MeCN resulted in the formation of two MeCN insertion products of 2 (4, 5). From different samples of synthesis products of this work a preferred hydrolysis product was obtained: [{(-pz*)2SiH}33-O]+Cl (6). The structural and electronic features of the compounds synthesised in this work were analysed with single-crystal X-ray diffraction and 29Si cross-polarisation (CP)/magic-angle spinning (MAS) NMR spectroscopy combined with quantum chemical computations to investigate their 29Si chemical-shift anisotropy principal tensor components.