Affiliation:
1. Institut für Anorganische Chemie der Universität Tübingen, Auf der Morgenstelle 18, D-72076 Tübingen, Germany
2. Institut für Organische Chemie der Universität Tübingen, Auf der Morgenstelle 18, D-72076 Tübingen, Germany
Abstract
2,3-Dihydro-1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene (1) reacts with an excess of hexafluorobenzene in the presence of boron trifluoride diethyletherate to give 1,3-diisopropyl-4,5- dimethyl-2-(perfluorophenyl)imidazolium tetrafluoroborate (2). Solutions of 2 exhibit an equilibrium consisting also of hexafluorobenzene and 2,2ʹ-(perfluoro-1,4-phenylene)bis(1,3-diisopropyl- 4,5-dimethylimidazolium)bis(tetrafluoroborate) (3) which is obtained from 1 and hexafluorobenzene in the ratio 2 : 1 on a preparative scale. Similar to 2, 2-(4-cyano-2,3,5,6-tetrafluorophenyl)-1,3- diisopropyl-4,5-dimethylimidazolium tetrafluoroborate (4), 2-(2,4-dicyano-2,5,6-trifluorophenyl)- 1,3-diisopropyl-4,5-dimethylimidazolium tetrafluoroborate (5), and 2-(4,6-difluoro-1,3,5-triazin-2- yl)-1,3-diisopropyl-4,5-dimethylimidazolium tetrafluoroborate (6) are obtained from 1 and perfluorobenzonitrile, 1,3-dicyano-2,4,5,6-tetrafluorobenzene, and 2,4,6-trifluoro-1,3,5-triazin, respectively. The FAB mass spectra of compounds 2 - 6 and the results of the crystal structure analyses of compounds 2 - 4 are discussed.