Instability of complexes containing the dicyclopentadienylvanadium(iv) group

Abstract

Abstract The preparation of complexes of the type (π‐C 5 H 5 ) 2 VR 2 has been attempted by reaction of one mole of vanadocene dichloride with two moles of an organo‐metallic reagent RM (RM = C 6 H 5 Na and C 6 F 5 Li); these reactions result in the formation of complexes of the type (π‐C 5 H 5 ) 2 VR. The reaction of vanadocene dichloride with 1,4‐dilithio‐1,2,3,4‐tetraphenylbutadiene results in the formation of a tarrish polymer, whereas the corresponding reaction starting from titanocene dichloride yields the green complex (π‐C 5 H 5 ) 2 Ti[C 4 (C 6 H 5 ) 4 ]. The failure of the preparation of complexes of the type (π‐C 5 H 5 ) 2 VR 2 is ascribed to steric reasons.