ABSTRACT
ABSTRACT: LaIII and 8-hydroxyquinoline-2-carboxyaldehyde-(benzoyl)hydrazone can form a binuclear and 1:1 metal-to-ligand stoichiometry complex by nine-coordination at LaIII center with the structure of [LaL(NO3)(DMF)2]2 indicated by X-ray crystal structural analyses. The ligand acts as a dibasic tetradentate ligand, binding to LaIII through the phenolate oxygen atom, nitrogen atom of quinolinato unit, the C=N group of methylene and –O-C=N-group of the benzoyldrazone side chain. Dimerization of the monomeric unit occurs through the phenolate oxygen atoms leading to a central planar four-membered (LaO)2 ring. In fact, lanthanide metal ions and structurally similar 8-hydroxyquinoline-2-carboxyaldehyde-aroylhydrazones can form a series of structurally similar binuclear and 1:1 metal-to-ligand stoichiometry complexes by nine-coordination at LnIII center with geometry of distorted edge-sharing mono-capped square-antiprism of [LnL(NO3)(DMF)2]2 (Ln = La3+, Nd3+, Sm3+, Eu3+, Gd3+, Tb3+, Dy3+, Ho3+, Er3+) except for YbIII complex by eightcoordination at YbIII center with geometry of distorted edge-sharing dodecahedron of [YbL(NO3) (DMF)]2. All these complexes, strongly binding to calf thymus DNA by intercalation with the binding constants at 0.1422~28.53 × 106 L·mol-1, may be used as potential anticancer drugs.
