The reactivity of titanium(IV) oxide dichloride towards nitrogen and oxygen donor molecules and a study of the complex anions TiOCl42– and TiOCl53–
Abstract
The direct reaction of titanium(IV) oxide dichloride with a range of ligand molecules leads to the formation of complexes of stoicheiometry TiOCl2,2L, (L = methyl cyanide, trimethylamine, tetrahydropyran, and tetrahydrofuran). With pyridine (py), ethylene glycol dimethyl ether (EGDE), and 1,4-dioxan the following complexes were obtained: TiOCl2,2·5py, TiOCl2,EGDE, and TiOCl2, 1·5C4H8O2. The latter complex can be used as a synthetic intermediate and its reaction with 2,2′-bipyridyl (bipy) and α-picoline (α-pic) results in the displacement of 1,4-dioxan and the formation of TiOCl2,bipy and TiOCl2,2α-pic. Only in the case of TiOCl2,2α-pic and TiOCl2,2NMe3 do i.r. spectral measurements indicate the presence of terminal TiO groups. The trimethylamine adduct is shown to be isostructural with its five-co-ordinate vanadium(IV) analogue. The probable structures of the other complexes are also discussed. Detailed electronic spectral measurements are reported for the TiOCl42– and TiOCl53– anions and the absorption bands assigned to transitions of the type halogen(π)→ Ti.