Two new heteroleptic pentacoordinated Zn(II) complexes (1 and 2) containing 4,4 0 -disubstituted 2,2 0bipyridines as the main ligand and curcumin (curc) as an ancillary ligand have been synthesized, spectroscopically and structurally characterized, and tested in vitro towards different human cancer cell lines. While the nitrogen ligands are almost inactive, Zn(II) curc derivatives 1 and 2 show promising and selective anticancer properties. In particular the curc Zn(II) complex 1 shows the strongest growth inhibition in all cell lines, being even more effective than the pure curc in the LAN-5 neuroblastoma cell line. Furthermore, the curc moiety makes the complexes 1 and 2 fluorescent, a feature enabling investigation of their interaction with DNA through a new optical method previously tested with the reference fluorescent intercalator ethidium bromide. This analysis demonstrates that the interaction mode of curc, 1 and 2 with DNA in the double helix favors their alignment perpendicular to the DNA axis, suggesting a partial inter-base intercalation of these Zn(II) 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. Moreover, their effect on cell survival signalling and/or inhibitors of the PC-3 cell cycle have been analyzed. The results indicate that 1-8 exhibit strong cytotoxic activity against all cell lines affecting key molecules such as p-AKT and p21 waf, involved in the cell proliferation and/or arrest. Zinc(II) is thus a promising alternative to Pt(II) ion in the design of new, better performing antitumour agents.

New Pt(ii) and Pd(ii) complexes with the metal center coordinated to two different chelating ligands, tropolone (trop) and dihexadecyl-2,2'-bipyridine-4,4'-dicarboxylate bipyridine (bipy), [(bipy)M(trop)][CF(3)SO(3)], have been synthesized and their biological evaluation has been performed demonstrating a remarkable cytotoxic activity in vitro against the human prostate DU145 and hormone-sensitive LNCaP cells lines. Moreover, for the Pt(ii) derivative, the molecular structure has been determined by single-crystal X-ray diffraction and computational analysis on the hydrolysis reaction mechanisms have been performed by density functional theory (DFT) calculations, in order to correlate molecular structure, biological activity and mechanism of action of this new class of complexes based on two different bioactive fragments.

Stoichiometric triethylamine in methanol deprotonates the imidazole and yields 98% sub-micrometric ZIF-90 with no residual solvent in the pores.