DNA cleavage activities of two dinuclear copper coordination polymers

The DNA cleavage activities of two coordination polymers of Robson-type macrocycles, {[Cu4L1(4,4′-bipy)2](ClO4)4·H2O}∞ (1) and {[Cu4L2(4,4′-bipy)4](ClO4)4·2CH3CN·2H2O}∞ (2) (where H2L1 and H2L2 are the [2 + 2] condensation products of 1,3-diaminopropane with 2,6-diformyl-4-methylphenol and 2,6-diformyl-4-fluorophenol, respectively), have been studied. The interactions of the complexes with calf thymus-DNA were investigated by UV–vis spectroscopy, CD spectroscopy, and gel electrophoresis. The binding constants of 1 and 2 are 7.2 × 104 and 2.1 × 105 M−1, respectively. The complexes exhibit DNA cleavage activity, with the cleavage process involving oxidative cleavage of DNA.