Polymer-supported trichlorotitanium(III) complexes and their dioxygen adducts.

Various polymer-supported trichlorotitanium(III) (TiCl3) complexes were prepared in pyridine or THF from TiCl3 and copolymers composed of 4-vinylpyridine (10, 20, and 65 mol%), divinylbenzene (0 and 20 mol%), and styrene. The ESR technique was employed for structural studies of titanium(III) species and their dioxygen adducts contained in the supported complexes. The supported complexes contained, as titanium(III) species, mainly (>88%) mixtures of TiCl3(pyr)nL3−n (n=1, 2, and 3), where pyr is a pyridyl group of the supports and L is a molecule of the solvents used in preparation. The relative amounts of the species having smaller n values increased with cross-linking, with a decrease in the content of pyridyl groups, and with pretreatment with tetra-chlorotitanium(IV) (TiCl4). On exposure to oxygen the supported complexes gave two or three kinds of dioxygen adducts (Ti(IV)–O2−) characterized by g1 the principal g value along the axis of O–O bond. The g1 values of three dioxygen adducts α, β and γ were 2....