Pentafluorophenyliodine(III) compounds. 4 [1] Aryl(pentafluorophenyl)iodoniumtetrafluoroborates: General method of synthesis, typical properties, andstructural features

Aryl(pentafluorophenyl)iodoniumtetrafluoroborates [Ar'Ar "I][BF4] (Ar' = C6 F5, Ar " = C6H5, o-C6H4F, m-C6H4F p-C6H4F, 2,6-C6H3F2, 3,5-C6H3F2, 2,4,6-C6 H2F3, 3,4,5-C6H2F3, C6F5) are prepared in good yields and high purity by th e reaction of C6F6IF2 with Ar " BF2 in CH2Cl2. This convenient method can b e applied generally to many iodonium compounds. Thermal and spectroscopic p roperties (H-1, C-13, F-19 NMR, IR, Raman) are reported and discussed. The solid state structures of six iodonium compounds show significant cation-an ion interactions which result in two different arrangements: a dimer with a 8-membered ring or polymers with infinite zigzag chains. Ab initio calcula tions on prototypes of aryliodonium cations show relations between the kind of the aryl group (C6H5 vs. C6F5) and structural parameters as well as cha rges. By means of F-19 NMR the sigma (1)- and sigma (R)-constants of the [C 6F5I](+)-substituent are determined.