Abstract
In this paper, three complexes of type [Co(en)2PIP]3+(PIP=2-phenylimidazo[4,5-f][1,10,] phenanthroline)(1), [Co(en)2IP]3+ (IP = imidazo[4,5-f][1,10,] phenanthroline)(2), and [Co(en)2phen-dione]3+(1,10 phenanthroline 5,6,dione)(3) have been synthesized and characterized by UV/VIS, IR, 1H NMR spectral methods. Absorption spectroscopy, emission spectroscopy, viscosity measurements, and DNA melting techniques have been used for investigating the binding of these two complexes with calf thymus DNA, and photocleavage studies were used for investigating these binding of these complexes with plasmid DNA. The spectroscopic studies together with viscosity measurements and DNA melting studies support that complexes 1 and 2 bind to CT DNA (= calf thymus DNA) by intercalation mode via IP or PIP into the base pairs of DNA, and complex 3 is binding as groove mode. Complex 1 binds more avidly to CT DNA than 2 and 3 which is consistent with the extended planar ring π system of PIP. Noticeably, the two complexes have been found to be efficient photosensitisers for strand scissions in plasmid DNA.
Highlights
The interaction of transition metal complexes with Calf thymus DNA (DNA) has been extensively studied in the past few years
Barton demonstrated that tris(phenanthroline) complexes of ruthenium(II) display enantiomeric selectivity in binding to DNA, which can be served as spectroscopic probes in solution to distinguish right- and left-handed DNA helies [5]
We choose to concentrate our work on cobalt(III) ethylenediamine polypyridyl complexes which have the same interesting characteristics and DNA cleaving properties as Ru(II) complexes
Summary
The interaction of transition metal complexes with DNA has been extensively studied in the past few years. Metal complexes of the type [M(LL)3]n+ where LL is either 1,10,phenathroline or modified phenanthroline ligand are attractive species to recognize and cleavage DNA [1,2,3,4]. Barton demonstrated that tris(phenanthroline) complexes of ruthenium(II) display enantiomeric selectivity in binding to DNA, which can be served as spectroscopic probes in solution to distinguish right- and left-handed DNA helies [5]. The ligands or the metal in these complexes can be varied in an controlled manner to facilitate an individual application. We choose to concentrate our work on cobalt(III) ethylenediamine polypyridyl complexes which have the same interesting characteristics and DNA cleaving properties as Ru(II) complexes. We have chosen ethylenediamine because in classical antitumor agent (cis platin) one of the ligands must be
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
