Synthesis of new organotitanium (IV) complexes Cp2Ti(SeR)2 and Cp2TiCl(SeR) via tandem reactions involving `Cp2Tiʹ intermediate. Crystal structures of Cp2TiCl(SeR) (R=p-ClC6H4, p-BrC6H4)

A simple and convenient route for synthesizing organotitanium (IV) complexes with a general formula Cp2Ti(SeR)2 or Cp2TiCl(SeR) has been developed. This synthetic route includes reduction of Cp2TiCl2 with Mg and an in situ treatment of the intermediate `Cp2Tiʹ with diselenides RSeSeR. Interestingly, while the route involving reaction of Cp2TiCl2, Mg and RSeSeR in a molar ratio of 1:1:1 produced Cp2Ti(SeR)2, (1–5, R=α-C10H7, o-MeC6H4, m-MeC6H4, p-ClC6H4, p-BrC6H4) in 91–97% yields, the route involving reaction of Cp2TiCl2, Mg and RSeSeR in a molar ratio of 1: 0.5: 0.5 afforded Cp2TiCl(SeR) (6–7, R=p-ClC6H4, p-BrC6H4) in 70% and 92% yields, respectively. 1–7 are new and have been characterized by elemental analysis and spectroscopy, as well as by X-ray diffraction analysis for 6 and 7. A possible pathway for production of these two types of organotitanium (IV) complexes, mainly depending upon the molar ratio of the starting materials, are briefly discussed.