Preparation and structures of complexes of titanium(IV) and 8-hydroxyquinoline: TiQ(2)(Opr(i))(2) and [TiQ(2)(mu-O)](4)center dot 6H(2)O

摘要

The reaction between Ti(OPr')(4) and 8-hydroxyquinoline (HQ) resulted in TiQ(2)(OPr')(2), 1 in 90% yield. Further reaction of 1 with water yielded [TiQ(2)(mu-O)](4) . nH(2)O, 2 . nH(2)O, n = 2 or 6 depending on whether the sample was dried. The structures of 1 and 2.6H(2)O were deter-mined by X-ray diffraction method. In I and 2 the bonding situations around the pseudo-octahedrally coordinated Ti(IV) are very similar. The two oxygen atoms from Q(-) ligands are trans to each other, while the two nitrogen atoms are cis to each other and trans to the other two oxygen atoms of OPr' in 1 and mu-O in 2. The [Ti(mu-O)](4) eight-membered ring is puckered. There is extensive hydrogen bonding of four water molecules with [TiQ(2)(mu-O)](4), two on each side of the eight-membered ring of [Ti(mu-O)](4). The two water molecules on the same face of the eight-membered ring are further hydrogen bonded to another water molecule. A novel feature in 2 is that the plane of each Q(-) ligand is parallel to that of another Q(-) ligand coordinated to a neighboring Ti(IV) in an eclipsed conformation. The average distance between the corresponding atoms in the parallel Q(-) ligands is 3.6 Angstrom. It is an indication that there is a strong non-bonding interaction between each pair of parallel Q- ligands. The hydrogen bonds and the non-bonding interactions lead to the most severely distorted plane of the [Ti(mu-O)](4) eight-membered ring. (C) 2002 Elsevier Science Ltd. All rights reserved. [References: 32]