Synthesis, characterization, solid-state photo-luminescence and anti-tumor activity of zinc(II) 4'-phenyl-terpyridine compounds.

Reactions between 4'-phenyl-terpyridine (L) and several Zn(II) salts (sulfate, nitrate, chloride or acetate) led to the formation of the complexes [Zn(2)(mu-O(2)SO(2))(2)L(2)(CH(3)OH)(2)] (1), [Zn(NO(3))L(H(2)O)]NO(3) (2), [Zn(Cl)(2)L] (3) and [Zn(CH(3)COO)(2)L] (4) which were characterized by IR, (1)H NMR and fluorescence spectroscopies, elemental analysis and single crystal X-ray diffraction. In the dinuclear molecule of 1 the Zn atom is hexacoordinated, with a N(3)O(3) coordination environment and forms an octagonal ZnOSOZnOSO metallacycle. In the remaining structures, the metal atom is envisaged as possessing highly distorted N(3)X(2) (X = O or Cl) square pyramid coordination geometries. The structure of 3 presents two different packing patterns which lead to distinct pi-pi stackings. In both structures 2 and 4, strong intermolecular hydrogen bonds were identified. The complexes exhibit promising in vitro tumor-inhibiting activities, which are higher than that of cisplatin, against the following human tumor cell lines: promyelocyticfina leukaemia (HL-60), hepatocellular carcinoma (Bel-7402), gastric carcinoma (BGC-823) and nasopharyngeal carcinoma (KB).