A New Class of Constrained-Geometry Metallocenes: Synthesis and Crystal Structure of a Carboranyl−Thiol-Appended Half-Sandwich Titanocene and Its Conversion to Halotitanocene

A novel carboranyl−thiol-appended cyclopentadiene ligand, 1-SH-2-[HCpCH(Ph)]-closo-1,2-C2B10H10 (2), was prepared and then reacted with Ti(NMe2)4 to form the corresponding titanium complex [1-(σ-S)-2-(η5-C5H4CH(Ph))-1,2-C2B10H10)]Ti(NMe2)2 (3), which undergoes exclusively a monohalogenation reaction on the metal center, in the presence of Me3SiCl or Me3NHCl, leading to the formation of [1-(σ-S)-2-(η5-C5H4CH(Ph))-1,2-C2B10H10)]TiCl(NMe2) (4) in 71% yield.