Multicomponent Mechanochemical Synthesis of Cyclopentadienyl Titanium tert-Butoxy Halides, CpxTiXy(OtBu)4–(x+y) (x, y = 1, 2; X = Cl, Br)

Titanium tert -butoxy halides of the formula Cp x TiX y (O t Bu) 4-( x + y ) ( x , y = 1, 2; X = Cl, Br) have been prepared thorough milling the reagents without solvent. In the case of the chloride derivatives, Cp 2 TiCl 2 is used as a starting material; in the case of the bromides, a mixture of LiCp, TiBr 4 , and Li[O t Bu] is used. The stoichiometric ratios of the starting materials are reflected in the major products of the reactions. Single-crystal X-ray structures are reported for Cp 2 TiCl(O t Bu), Cp 2 TiBr(O t Bu), and CpTiBr 2 (O t Bu), as well as for Cp 2 TiCl(O i Pr) and a redetermination of Cp 2 TiCl(OMe). The tert -butoxy derivatives are notable for their nearly linear Ti-O-C angles (>170°) that reflect Ti-O π-bonding, an interpretation supported with density functional theory calculations.