Molecular structures of a series of substituted bis(η5‐cyclopentadienyl)titanium dihalides CpR2TiX2 [X = F,Cl, Br and I; R = CHPh2, CH(p‐Tol)2 and adamantyl]

Metallocene dihalides and derivatives thereof are of great interest as precursors for catalysts in polymerization reactions, as antitumor agents and, due to their increased stability, as suitable starting materials in salt metathesis reactions and the generation of metallocene fragments. We report the synthesis and structural characterization of a series of eleven substituted bis(η⁵‐cyclopentadienyl)titanium dihalides, namely bisη⁵‐1‐(diphenylmethyl)cyclopentadienyl]difluoridotitanium(IV), Ti(C₁₈H₁₅)₂F₂], bis{η⁵‐1‐bis(4‐methylphenyl)methyl]cyclopentadienyl}difluoridotitanium(IV), Ti(C₂₀H₁₉)₂F₂], and bis{η⁵‐1‐bis(adamantan‐2‐yl)methyl]cyclopentadienyl}difluoridotitanium(IV), Ti(C₁₅H₁₉)₂F₂], together with the bromide and iodide analogues, and the chloride analogues of the diphenylmethyl and adamantyl complexes. These eleven complexes were prepared by the reaction of the corresponding bis(η⁵:η¹‐pentafulvene)titanium complexes with different hydrogen halides (Cl, Br and I). The titanocene fluorides become available via chloride–fluoride exchange reactions.