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.