Bis(μ-2-hydroxymethyl-2-methylpropane-1,3-diolato)bis[dichloridotitanium(IV)] diethyl ether disolvate

Abstract

The title complex, [Ti2Cl4{CH3C(CH2O)2(CH2OH)}2], lies across a centre of symmetry with a diethyl ether solvent mol­ecule hydrogen bonded to the –CH2OH groups on either side of it. The TiIV atom is coordinated in a distorted octa­hedral geometry by a tripodal ligand and two terminal chloride atoms. There are three coordination modes for the tripodal ligand distinguishable on the basis of their very different Ti—O bond lengths. For the terminal alkoxo ligand, the Ti—O distance is 1.760 (1) Å, the asymmetric bridge system has Ti—O bond lengths of 1.911 (1) and 2.048 (1) Å. The Ti—O bond length for the alcohol O atom is the longest at 2.148 (1) Å.

Framework robustness in early d-block metal complexes with tripodal polyalcohol ligands

“…The average TiO bond length in the asymmetric bridge is 2.0247 Å, while the longest metal-oxygen distance (2.1064(8) Å) involves the terminal OH group. Similar dimensions were reported by Nielson and co-workers for a Ti IV 2 Me2Et 2 O complex obtained in a small amount from TiCl 4 in diethyl ether [32].…”

“…One example, containing chromium(III) and 1,1,1-tris(hydroxymethyl)propane (H 2 L Et ), was obtained from the in situ oxidation of a Cr II starting material under reflux in methanol [13]. The other works involve fully-oxidized metal ions such as Ti IV , V V , and W VI [31][32][33]. As an example, complex [Ti IV 2 Cl 4 (HL Me ) 2 ]•2OEt 2 is structurally analogous to the product Cr 2 Me introduced herein, except for the oxidation state +IV for the metal accompanied by only one (non-deprotonated) hydroxyl moiety on the tripodal ligand, and diethyl ether as crystallization solvent [32].…”

“…The other works involve fully-oxidized metal ions such as Ti IV , V V , and W VI [31][32][33]. As an example, complex [Ti IV 2 Cl 4 (HL Me ) 2 ]•2OEt 2 is structurally analogous to the product Cr 2 Me introduced herein, except for the oxidation state +IV for the metal accompanied by only one (non-deprotonated) hydroxyl moiety on the tripodal ligand, and diethyl ether as crystallization solvent [32]. Elemental analysis of this compound suggests loss of solvating Et 2 O, in line with similar observations made in the present work.…”