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 [Zn2(μ-O2SO2)2L2(CH3OH)2] (1), [Zn(NO3)L(H2O)]NO3 (2), [Zn(Cl)2L] (3) and [Zn(CH3COO)2L] (4) which were characterized by IR, 1H 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 N3O3 coordination environment and forms an octagonal ZnOSOZnOSO metallacycle. In the remaining structures, the metal atom is envisaged as possessing highly distorted N3X2 (X = O or Cl) square pyramid coordination geometries. The structure of 3 presents two different packing patterns which lead to distinct π–π 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).

Figure optionsDownload as PowerPoint slideThe reactions of 4′-phenyl-terpyridine with Zn(II) salts led to the formation of zinc complexes which were fully characterized and shown to exhibit photo-luminescence in solid state at room temperature and promising in vitro tumor-inhibiting activities against several human tumor cell lines.