Crystal structure, antitumor activities and DNA-binding properties of the La(III) complex with Phthalazin-1(2H)-one prepared by a novel route

Phthalazin-1(2H)-one was prepared by a novel route. The La(III)-complex of phthalazin-1(2H)-one, [La(NO3)3 · 4H2O · C8H7N2O] · H2O, was synthesized and characterized on the basis of elemental analysis, thermal analyses (TG/DTA) and X-ray crystallography. In the complex, the coordination number of the La(III) ion is eleven. The interaction of the ligand and its complex with calf thymus DNA was investigated by spectrophotometric methods and viscosity measurements, respectively. Experimental results indicated that phthalazin-1(2H)-one and the complex can bind to DNA by intercalation modes, but the binding affinity of La(III)-complex is higher than that of the ligand. Comparative antitumor activities of La(III)-complex was investigated by HL-60 and A-549. IC50 = 2.6 × 10−8, 3.3 × 10−5 mg/mL are given.