Low-Valent Pentafulvene Titanium Dinitrogen Complex as a Precursor for Cationic Titanium Complexes

Treatment of titanium dinitrogen complex [Cp*(η6-C5H4C10H14)Ti]2(μ-N2) (1) with ferrocenium borate, [Cp2Fe][BPh4], in THF results in oxidation of the titanium center, affording the titanium(IV) pentafulvene compound [Cp*(η6-C5H4C10H14)Ti(THF)][BPh4] (2). Treatment of 1 with anilinium reagent [PhNMe2H][BPh4] results in the formation of cationic titanocene(III) complexes. In THF, the titanocene cation is stabilized by two THF solvent molecules, whereas the tetraphenylborate anion is bound to the metal center when the reaction is performed in toluene as a solvent. Treatment of 1 with B(C6F5)3 affords zwitterionic [Cp*{η5-C5H3(C11H14)(B{C6F5}3)}Ti(THF)] (7). Results show the versatility of pentafulvene complex 1 in the preparation of cationic titanium complexes.