REDETERMINATION OF THE CRYSTAL-STRUCTURE OF 3,5,7-TRIMETHYL-1-ADAMANTYL UNDECAFLUORODIANTIMONATE(V)

The crystal structure of the 3,5,7-trimethyl-1-adamantyl cation (1) ha s been redetermined by X-ray diffraction at 103 K, since the structura l data already published [Laube (1986a). Angew. Chem. 98, 368-369; Lau be (1986b). Angew. Chem. Int. Ed. Engl. 25, 349-350] showed a poor R-v alue (0.070) and exhibited a rather large variety of lengths of chemic ally but not crystallographically equivalent bonds, which is no longer present in the newly determined structure with R1 = 0.0452. A partial disorder model of the anion could be refined and the experimental dat a of (1) are compared with results of semi-empirical and ab initio cal culations. The results are interpreted in terms of stabilization of (1 ) by C,C-hyperconjugation. The detailed experimental procedure for the synthesis and crystallization of (1).Sb2F11 is described.