The complexes of norfloxacin (NFLX＝C16H18FN3O3), ciprofloxacin (CPLX＝C17H18FN3O3) with palladium ion [(NFLXH)2[PdCl4]•2H2O (1), (CPLXH)2[PdCl4]•2H2O (2)] were synthesized under an acidic condition. Complex 1 is orange crystal and complex 2 is brown powder. By means of elemental analysis, IR, UV and molar conductance, the structures of the complexes were characterized. The structure of 1 was determined by single crystal X-ray crystallography, which is of triclinic space group P-1 with a＝0.84561(17) nm, b＝0.94191(19) nm, c＝1.2832(3) nm; α＝111.26(3)°, β＝97.23(3)°, g＝96.38(3)°, V＝0.9312(4) nm3, Z＝1, R＝0.040 and wR＝0.088. The interactions between the complexes and ct-DNA were studied by ultraviolet absorption spectroscopy and fluorescence spectroscopy, indicating that the binding mode is intercalation and the binding constants (Kb) of the complexes with DNA respectively is: 2.06×104 (1), 2.43×104 (2). Antiproliferative activities of the complexes to tumors in vitro were tested by using an 3-[4,5-Dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) method, showing that the complexes have more powerful inhibition effects on A549 cells and on HL-60 cells growth than quinolone itself. 2 has obvious inhibition effect on A549 cells growth: inhibition ratio on A549 cells reached (95.4±3.7)% and its IC50 (72 h) on A549 cells was (124.5±10.3) μmol•L－1.

Key words: quinolone, norfloxacin, ciprofloxacin, palladium, DNA, antiproliferative activity