Synthesis, Structural Characterization, and Reactivity of a Fluorene-Based Calcium Oxycyclopentadienide Complex

Direct deprotonation of 9-fluorenol with Ca­[N­(SiMe3)2]2 efficiently generated a fluorene-based calcium oxycyclopentadienide complex, which is the first alkaline earth metal complex containing an oxycyclopentadienyl dianion ligand. The η5, η1, and η2 interactions between the oxycyclopentadienyl dianion ligand and the calcium center were observed in the solid state. The calcium oxycyclopentadienide complex displayed reductive character and multiple reactive sites. Its reactivity toward a range of electrophiles, especially acid chlorides, was investigated and discussed in detail. A wide variety of fluorene derivatives were synthesized.