Indenyl- and Fluorenyl-Functionalized N-Heterocyclic Carbene Complexes of Titanium, Zirconium, Vanadium, Chromium, and Yttrium

Dimethylindenyl-functionalized N-heterocyclic carbene complexes of titanium(IV), titanium(III), zirconium(IV), and vanadium(III) were prepared from potassium indenylcarbenes by salt elimination reactions. X-ray diffraction studies revealed that in the complexes the ligand adopts a bidentate coordination mode. Alkanolysis of a dimethylindene-functionalized imidazolium salt with Y(CH2SiMe3)3(THF)2 gave rise to a dimeric yttrium bromo alkyl in which the ligand adopts a bidentate coodination mode. Aminolysis of the fluorene-functionalized imidazolium salts with {[Cr(N(SiMe3)2)2(THF)2} led to chromium(II) complexes in which the ligand adopts a monodentate binding mode via the N-heterocyclic carbene end with dangling fluorene groups.