Structure Determination of Silyl Cations in Solution

The NMR/ab initio/IGLO method can provide this information provided reliable NMR chemical shifts are available from experiment. In the following, we 

Comparison of experimental and theoretical NMR chemical shifts suggested the existence of complexes III and/or IV in solution. [43] It was found that formation of these complexes in solution is influenced by three major factors, namely 

1) the steric bulk of solvent S as well as that of substituents R attached to the positive Si atom, 

Interaction distances Si-S are shorter by 0.01 - 0.04 A in solution than in the gas phase. This is due to the polarisation of both S and R3Si+ within the solvent cage indicated by a larger charge transfer in the solvated complex (Table 5), which is comparable with what was found for the BH3NH3 donor-acceptor complex. [38] 

Some properties of Me3Si(S)+ complexes 37 - 40 in gas and solution phases. [43]a 

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