Controlled hydrolysis reactions of solvated [TiCln](4–n)+ species. Crystal and molecular structures of [Mg(MeCN)6][{TiCl4(MeCN)}2(µ-O)]·4MeCN and [{TiCl2(MeCN)2(µ-O)}4]·2MeCN

Abstract

Partial hydrolysis reactions of the solvated [TiCl₅(MeCN)]^– anion and of the adduct TiCl₄·2MeCN gave the µ-oxo-dititanium anion [{TiCl₄(MeCN)}₂(µ-O)]^2– and the neutral tetranuclear µ-oxo compound [{TiCl₂(MeCN)₂(µ-O)}₄], respectively, as established by X-ray crystallographic studies. Crystals of [Mg(MeCN)₆][{TiCl₄(MeCN)}₂(µ-O)]·4MeCN 1 are monoclinic, space group P2₁/n, a= 14.777(6), b= 14.603(6), c= 21.214(10)Å, β= 105.3(1)°. The structure contains discrete octahedral [Mg(MeCN)₆]²⁺cations, [{TiCl₄(MeCN)}₂(µ-O)]^2– anions and solvent (MeCN) molecules. Crystals of [{TiCl₂(MeCN)₂(µ-O)}₄]·2MeCN 2 are orthorhombic, space group P2₁2₁2₁a= 12.165(6), b= 12.367(6), c= 27.927(11)Å. The structure contains discrete [{TiCl₂(MeCN)₂(µ-O)}₄] units and solvent (MeCN) molecules. In 1 both titanium atoms have an octahedral environment. The Ti–O–Ti bridge is approximately linear [174.7(3)°] with equivalent Ti–O distances of 1.783(4) and 1.764(4)Å. By contrast in 2 there are four Ti–O–Ti bridges but in each case the two Ti–O distances are significantly different with mean values of 1.668,1.954 Å.