Isomer abundance of bis(beta-diketonato) complexes of titanium(IV). Crystal structures of the antitumor compound budotitane [Ti-IV(bzac)(2)(OEt)(2)] and of its dichloro-derivative [Ti-IV(bzac)(2)Cl-2] (bzac=1-phenylbutane-1,3-dionate)

摘要

The molecular tumor inhibiting titanium compound budotitane [Ti-IV(bzac)(2)(OEt)(2)] (1) and its dichloro-derivative [Ti-IV(bzac)(2)Cl-2] (2) (bzac=1-phenylbutane-1,3-dionate) have been crystallized and characterized by X-ray crystallography and further physical methods. Budotitane (1) crystallizes in the tetragonal, non-centrosymmetric space group P4(1) with two molecules in the asymmetric unit. Both molecules adopt the cis-cis-trans configuration with the acetyl ends of the benzoylacetonate ligands in the trans position. The dichloro-derivative of budotitane, [Ti-IV(bzac)(2)Cl-2] (2) crystallizes in the monoclinic, centrosymmetric space group P2(1) with one molecule only in the asymmetric unit. In contrast to budotitane (1), (2) shows a cis-trans-cis arrangement with the benzoyl groups in the trans position. In both complexes there are equal numbers of Delta and Delta enantiomers within the unit cell. The phenyl groups in (1) as well as in (2) are in approximately coplanar conjugation to the metal enolate rings. The thermal degradation of budotitane (1) was investigated 2 in the temperature range from 25 degreesC up to 800 degreesC and reveals the formation of (TiO)-O-IV(bzac(2-)) as an intermediate and of the rutile phase of TiO2 as a final product. It may be worthwhile to introduce budotitane in the form of isomerically pure crystals in the preparation of the drug used for future tests. (C) 2003 Elsevier Science Inc. All rights reserved. [References: 28]