Synthesis and characterization of water‐soluble copper(II), cobalt(II) and zinc(II) complexes derived from 8‐hydroxyquinoline‐5‐sulphonic acid: DNA binding and cleavage studies. (24th January 2017)

• Record Type: Journal Article
• Authors: Gubendran, Ammavasi; Kesavan, Mookkandi Palsamy; Ayyanaar, Srinivasan; Raja, Jeyaraj Dhaveethu; Athappan, Periyakaruppan; Rajesh, Jegathalaprathaban
• Is Part Of: Applied organometallic chemistry. Volume 31:Number 9(2017:Sep.)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2017-01-24
• Subjects: 8‐hydroxyquinoline -- CD spectra -- DNA binding studies -- gel electrophoresis -- metal(II) complexes; Organometallic chemistry -- Periodicals; Organometallic compounds -- Periodicals; 547.05
• DOI: 10.1002/aoc.3708
• Languages: English
• ISSNs: 0268-2605

Abstract

Abstract : Three water‐soluble complexes, [Cu2 L2 Cl2 ] (1 ), [CoL2 (im)2 ] (2 ) and [ZnLClH2 O] (3 ) (HL = 8‐hydroxyquinoline‐5‐sulphonic acid; im = N ‐methylimidazole), were prepared and characterized using various spectral techniques. The DNA binding behaviour of complexes1 –3 was studied using UV–visible and circular dichroism (CD) spectra and cyclic voltammetry. All three complexes exhibit hypochromism but complexes1 and3 alone give a red shift of 4 nm with a significant binding constant of K b = 2.1 × 10 4 and 1.0 × 10 4 M −1, respectively, but complex2 shows no red shift with lower K b of 4.1 × 10 3 M −1 . The voltammetric E 1/2 of complex1 on interaction with herring sperm DNA shifts to a more positive potential, as expected, than complex2 due to higher DNA affinity. Additionally, analysis of electrochemical data yields a value of K + / K 2+ greater than one suggesting that complex1 binds to DNA through intercalation in the M(I) state. Evidently in CD spectral analysis, complex1 exhibits a decrease in molar ellipticity with a red shift of 10 nm and a significant decrease in intensity compared to complexes2 and3 . This clearly indicates that complex1 induces the B → A transition to a greater extent than2 and3 . Oxidative cleavage using circular plasmid pUC18 DNA with complex1 was investigated using gel electrophoresis. Interestingly, complex1 displays a strong DNA binding affinity and is efficient in cleaving DNA in the presence of H2 O2 at pH = 8.0 at 37 °C. Abstract : Three water‐soluble complexes of Cu(II), Co(II) and Zn(II) containing 8‐hydroxyquinoline‐5‐sulfonic acid ligand were prepared and characterized. From the results of spectroscopic and electrochemical methods, all three complexes have significant interactions with DNA. Oxidative cleavage studies using circular plasmid pUC18 DNA with the Cu(II) complex were conducted using gel electrophoresis.