The first dinuclear copper(ii) and zinc(ii) complexes containing novel Bis-TACN: syntheses, structures, and DNA cleavage activities

Abstract

Two novel binuclear complexes [Cu(2)(L)].(ClO(4))(2) (1) and [Zn(2)(L)].(ClO(4))(2) (2) were synthesized and crystallographically characterized {L = 1(4),5(4)-dimethyl-1(2),5(2)-dihydroxy-1(1,3),5(1,3)-dibenzene-3(1,4),7(1,4)-di-1,4,7-triazacyclononane}. The cation [Cu(2)(L)](2+) structure of 1 is similar to that of [Zn(2)(L)](2+) of 2. The central ion is bridged by the di-phenoxo of L and lies in a close to perfect square pyramidal geometry. 1 and 2 crystallize in the triclinic space group P1. The two complexes effectively promote the cleavage of plasmid DNA in the presence of activating agents at physiological pH and temperature. The pseudo-Michaelis-Menten kinetic parameters k(cat) = 1.61 h(-1), K(m) = 1.35 x 10(-5) M for complex 1 in the presence of mercaptoethanol; k(cat) = 2.48 h(-1), K(m) = 5.5 x 10(-5)M for complex 2 in the presence of hydrogen peroxide were obtained. The mechanism of plasmid DNA cleavage was studied by adding standard radical scavengers. DNA cleavage reaction by the binuclear Zn(II)/H(2)O(2) system is a hydrolytic mechanism.

4,4'-(DIPHENYLMETHANE-4,4'-DIYLDINITRILO)DIPENTAN-2-ONE AND 4,4'-(DIPHENYLETHER-4,4'-DIYLDINITRILO)DIPENTAN-2-ONE LIGANDS AND THEIR Ni(II), Cu(II) COMPLEXES: SYNTHESIS, CHARACTERIZATION, DNA CLEAVAGE STUDIES

“…But (3) and (5) are less effective than complexes (4) and (6). On the other hand, the pBR322 DNA treated with the ligands (3)(4)(5)(6)(7)(8) are remarkably degrading the pBR322 DNA by oxidative (O 2 -dependent pathway) cleavage mechanism using the singlet oxygen as the reactive species [44,46]. These results are similar to that observed for some Cu(II) and Ni(II) complexes as chemical nuclease [47][48][49][50][51][52]. )…”

Synthesis, Crystal Structure, DNA Binding, and Hydrolytic Cleavage Activity of a Manganese(II) Complex

“…[16][17][18] In an attempt to obtain more insight into the selectivity and efficiency of DNA recognized and cleaved by different complexes, herein we have synthesized and characterized a dichlorido-bridged trinuclear manganese(II) complex of the bpma ligand, namely, {[MnCl(bpma)] 2 [Mn(µ-Cl) 4 (H 2 O) 2 ]}·CH 3 CN (1) (Scheme 1). A detailed study of the magnetic properties was also carried out.…”

Crystal structure, DNA binding studies, nucleolytic property and topoisomerase I inhibition of zinc complex with 1,10-phenanthroline and 3-methyl-picolinic acid

“…However, simple zinc(II) complexes with simple organic ligands having similar DNA sequence binding recognition are rare. Numerous zinc complexes are reported to be able to hydrolytically cleave DNA and RNA (Li et al 2009;Bazzicalupi et al 2008;Mancin and Tecilla 2007;Qian et al 2007;Boseggia et al 2004). However, some zinc complexes need activation by exogenous agent or a change in chemical environment or reaction condition for DNA cleavage (Ramakrishnan and Palaniandavar 2008;Seng et al 2008).…”