Crystal structure and antitumor activity of some rare earth metal complexes with Schiff base

The ligand 1-phenyl-3-methyl-5-hydroxy-4-pyrazolyl phenyl ketone (PMBP) isonicotinoyl hydrazone (H2L) was prepared by condensation of PMBP with isoniazid. Seven complexes of ran earth metals with H2L were synthesized and characterized on the basis of elemental analyses, IR, UV, H-1 NMR spectra and thermal analyses. The general formula of the complexes is Ln(HL)(3).3.5H(2)O (where Ln(III) = La, Eu, Gd, Tb, Dy, Ho and Er). X-ray diffraction analysis showed that the coordination polyhedron of the Eu complex is a tricapped trigonal prism. The La and Eu complexes possess antitumor activity, and the inhibitory rates for leukemia cells (L-1210) are 87.1% and 78.5%, respectively. (C) 2000 Elsevier Science B.V. All rights reserved.