Properties of Silylium Ions in the Gas Phase

In view of the many controversial experimental observations that were reported, an investigation of possible interactions of R3Si+ with solvent molecules S was needed. Considering the many limitations of experiment, it was clear that such a description had to be given by ab initio calculations. [41] Of course, the first step of such an investigation was to determine the properties of silylium ions in the gas phase. These properties represent appropriate reference data that have to be considered when assessing the degree of silylium ion character retained in solvated silyl cations. 

DZ+P or better basis sets are similar suggesting that these methods give a reasonable description of geometrical parameters. [639-48] 

DFT/IGLO NMR chemical shifts, 3prc(Si) populations and Si charges of silylium cations 1 - 4. a 

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