REDETERMINATION OF THE CRYSTAL-STRUCTURE OF THE 1,2,4,7-ANTI-TETRAMETHYLBICYCLO[2.2.1]HEPTAN-2-YL CATION) AT 110 K

The structure of the 1,2,4,7-anti-tetramethyibicyclo[2.2.1]heptan-2-yl cation (1) was redetermined by X-ray crystal structure analysis of it s Sb2F11 salt at 110 K (P2(1)/c, R1=5.76%). The most important structu ral features of 1 are: C(1)-C(2)=1.409(9), C(1)-C(6)=1.710(8), and C(2 )...C(6)=2.113(9) Angstrom and C(2)-C(1)-C(6)84.7(4)degrees. These res ults agree with those obtained earlier by other methods for the rapidl y equilibrating, partially sigma-delocalized 1,2-dimethylbicyclo[2.2.1 ]heptan-2-yl cation (2). The detailed experimental procedure for the p reparation of crystalline 1.Sb2F11 and the crystal selection and mount ing are described.