Trichloro(cyclopentadienyl)titanium

Abstract

[1270-98-0] C5H5Cl3Ti (MW 219.33) InChI = 1S/C5H5.3ClH.Ti/c1-2-4-5-3-1;;;;/h1-5H;3*1H;/q;;;;+3/p-3 InChIKey = AENCLWKVWIIOQH-UHFFFAOYSA-K (preparation of various cyclopentadienyltitanium(IV) complexes,1 e.g. enantioselective templates by exchanging two of the chloride ligands with chiral alkoxides;2 replacement of the third chloride by allyl groups3 or by ester enolates4 affords reagents for stereoselective allyltitanation of aldehydes2b,3 and for aldol reactions,4 respectively; combination with metal hydrides or with n-BuLi results in low-valent species, reagents for various reductions;5 catalysts for alkene polymerizations are obtained by activation with organoaluminum compounds, methylaluminoxane, or aluminosilicates;6 Ti–imido complexes derived from primary amines undergo intramolecular cyclizations with triple bonds;7 the Lewis acidity is used to cleave epoxides and acetals;8 methyl or ethyl derivatives can be used for the chemoselective alkyltitanation of aldehydes in the presence of ketones9) Physical Data: mp 208–211 °C (benzene); crystal structure.10 Solubility: sol aromatic hydrocarbons (toluene, dichlorobenzene, xylene), CH2Cl2, CHCl3, Et2O, THF, similar aprotic solvents. Form Supplied in: yellow-orange powder or crystals. Analysis of Reagent Purity: 1H NMR δ (CDCl3): 7.06 ppm (impurity, partial hydrolysis: 6.92 ppm); 13C NMR: 123.4 ppm (impurity: 122.2 ppm). Preparative Methods: the title reagent CpTiCl3 1 is most conveniently prepared by ligand redistribution between Dichlorobis(cyclopentadienyl)titanium and Titanium(IV) Chloride,1, 11 or by reaction of 1-trimethylsilyl-2,4-cyclopentadiene with TiCl4.12 Another method involves chlorination of Cp2TiCl2 with Sulfuryl Chloride/Thionyl Chloride13 or titanation of cyclopentadienyl-Tl.14 Purification: by recrystallization in the presence of HCl(g)1, 11 followed by sublimation in high vacuum.10 Handling, Storage, and Precautions: the crystalline solid must be protected from moisture and prolonged exposure to UV light should be prevented. Reactions should be carried out in dry equipment with absolute solvents in an inert atmosphere (Ar, N2).