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

The multinuclear silicon complexes [{H 2 ClSi(μ‐pz*) 2 } 2 SiH 2 ] ( 1 ) and [Cl 2 Si(μ‐pz RR ) 2 SiCl 2 ] ( 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: [{(μ‐pz*) 2 SiH} 3 –μ 3 ‐O] + Cl – ( 6 ). The structural and electronic features of the compounds synthesised in this work were analysed with single‐crystal X‐ray diffraction and 29 Si cross‐polarisation (CP)/magic‐angle spinning (MAS) NMR spectroscopy combined with quantum chemical computations to investigate their 29 Si chemical‐shift anisotropy principal tensor components.