Carbazolylsilanes: Synthesis and crystal structures

Abstract

Carbazole reacts with n-BuLi and fluorosilanes to give the lithium carbazolide (1) which crystallizes as a dimer from THF. In the reactions of 1 and difluorosilanes, F2SiR2, the carbazolylsilanes C12H8N-SiFR2 (2-4 R = Me (2), i Pr (3), t-Bu (4)), are obtained. Bis(carbazolyl)silanes, (C12H8N)(2)SiFR, are formed in the reaction of 1 with trifluorosilanes, F3SiR, in a molar ratio of 2:1, R = t-Bu (5), Ph (6), Me (7). Using F3SiMe and 1 in a molar ratio of 1:3 the tris(carbazolyl)silane (C12H8N)(3)SiMe (8) is isolated. The carbazolylfluorosilane 3 reacts with n-BuLi to give 1 and n-butyl-diisopropylfluorosilane, or with lithium pyrrolide to give carbazolyl(-diisopropyl)pyrrolylsilane (9). Lithiumpyrrolide cleaves the Si-NC12H8-bond of 9 and forms the diisopropyl-bis(pyrrolyl)silane 10. The crystal structures of 5, 6 and 7 have been determined and are discussed.