Synthesis of the Phenoxonium Cation of an α-Tocopherol Model Compound Crystallized with Non-Nucleophilic [B(C<sub>6</sub>F<sub>5</sub>)<sub>4</sub>]<sup>-</sup> and (CB<sub>11</sub>H<sub>6</sub>Br<sub>6</sub>)<sup>-</sup> Anions

The phenoxonium cation of a vitamin E model compound has been crystallized using the non-nucleophilic carborane and tetrakis(pentafluorophenyl)borate counteranions. The crystal structures confirm the assignment of the unusually stable phenoxonium cation and indicate that there is a substantial shortening of the carbon−oxygen bond lengths of the para-carbon atoms in the phenolic ring and a substantial increase of the carbon−oxygen bond length at the quaternary carbon. The crystallographic data are in excellent agreement with structural predictions from molecular orbital calculations.