Non-classical anticancer agents: synthesis and biological evaluation of zinc(II) heteroleptic complexes.

New heteroleptic complexes (1-8) containing Zn(II) ion coordinated to an N,N-chelating ligand (the 4,4'-dinonyl-2,2'-bipyridine, bpy-9) and to diketonates L such as tropoloids (Tropolone and Hinokitiol) or 1-phenyl-3-methyl-4-R-5-pyrazolones have been synthesized by using different stoichiometric ratio with respect to the L ancillary ligand. The molecular structure of the bis-tropolonate derivative [(bpy-9)Zn(L)(2)] 5 has been determined by single-crystal X-ray diffraction. The antitumour activity of all Zn(II) complexes was tested in vitro against three different human prostate cancer cells: DU145, LNCaP and PC-3.