Wheland a-complex

The postulated silicenium cations are covalently bonded C-centered -complexes between SiR3+ and aromatic solvents. Formally, these may be described as Wheland a complexes, in which the silicenium cation character is totally lost. 

Even before Pauling s criticism was published in Science as a technical comment, [27] elaborate ab initio calculations had been carried out by Olsson and Cremer [39], Schleyer, Apeloig, and co-workers [131], and Olah and co-workers [21,22], These investigations unanimously showed that a R3Si+ cation in aromatic solvents immediately forms a Wheland a-complex with a solvent molecule as shown in Scheme 9 for the case of benzene. Hence, one obtains a carbocation rather than a silylium cation in aromatic solvents. 

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