Structural Studies of {9-[2-(Dimethylamino)ethyl]fluorenyl}lithium Compounds

Two lithium compounds of the substituted fluorenyl ligand 9-[2-(dimethylamino)ethyl]fluorenyl (FlN) have been prepared and isolated. The X-ray crystal structures of FlNLi·Et2O (2) and FlNLi·2THF (3) have been obtained. In 2 the lithium atom is coordinated η5 to the fluorenyl anion while 3 exhibits an η2 arrangement. Structural details have been analyzed to provide additional insights regarding the nature of the lithium-π interactions in organolithium compounds with delocalized π-systems.