Mixed ligand copper(II) complexes of 2,9-dimethyl-1,10-phenanthroline: Tridentate 3N primary ligands determine DNA binding and cleavage and cytotoxicity.

Mixed ligand copper(II) complexes of 2,9-dimethyl-1,10-phenanthroline: Tridentate 3N primary ligands determine DNA binding and cleavage and cytotoxicity. J Inorg Biochem. 2014 Aug 7;140C:202-212 Authors: Ganeshpandian M, Ramakrishnan S, Palaniandavar M, Suresh E, Riyasdeen A, Akbarsha MA Abstract A series of mononuclear mixed ligand copper(II) complexes of the type [Cu(L)(2,9-dmp)](ClO4)21-4, where L is a tridentate 3N ligand such as diethylenetriamine (L1) (1) or N-methyl-N'-(pyrid-2-yl-methyl)ethylenediamine (L2) (2) or di(2-picolyl)amine (L3) (3) or bis(pyrid-2-ylmethyl)-N-methylamine (L4) (4) and 2,9-dmp is 2,9-dimethyl-1,10-phenanthroline, has been isolated and characterized. The complexes 1 and 3 possess square-based pyramidal coordination geometry. Absorption spectral studies reveal that the intrinsic DNA binding affinity varies as 1>2>3>4. The higher DNA binding affinity of 1 arises from L1, which offers lower steric hindrance toward intercalation of 2,9-dmp co-ligand into DNA base pairs and is involved in hydrogen bonding interaction with DNA. Interestingly, all the complexes cleave pUC19 supercoiled DNA in the absence of an activating agent. They also exhibit oxidative (H2O2) DNA cleavage ability, which varies as 1>2>3>4, the highest cleavage efficiency of 1 being due to the largest amount of ROS it generates. The tryptophan emission-quenching experiment reveals that the stronger binding of 3 and 4 with bo...
Source: Journal of Inorganic Biochemistry - Category: Biochemistry Authors: Tags: J Inorg Biochem Source Type: research