Microwave Synthesis, Characterization And Study On The Binding To DNA By Spectrophotometry For Some Novel Functional Polypyridine Complexes

In this paper, the mechanism and properties of microwave irradiation and its applications in both organic and inorganic synthesizing field were introduced. Studies on the electrochemical and spectral characteristics of polypyridly complexes, binding-modes of polypyridly complexes binding to DNA and factors affecting the binding of complexes to DNA are reviewed. Experimental methods forstudying mechanisms of complexes binding to DNA are introduced, including UV, Fluorescence, NMR and Electrochemistry.Two novel functional polypyridly cobalt complexes of [Co(H2bzimpy)2](ClO4)2 ( H2bzimpy = 2,6-bis(benzimidazol-2-yl) pyridine) and [Co(5-NO2-phen)2dppz](ClO4)3 (5-NO2-phen = 5-Nitro-1.10-phenanthroline, dppz = dipyrido[3,2-a;2 , 3 -cjphenazine) was synthesized by microwave irradiation method. The electrochemical behaviors of the complexes have been investigated by cyclic voltammetry and differential pulse voltammetry techniques, and theelectronic absorption spectroscopy and fluorescence spectroscopy ofthe complexes were determined at room temperatu e.The cyclic voltammpgram of the complex [Co(H2bzimpy)2]2+ have shown a quasi-reversible Co(III)/ Co(II) redox couple at 0.601V vs SCE and a reversible Co(II)/Co( I ) redox couple at -0.908V vs SCE. In addition, the complex [Co(H2bzimpy)2]2+ displayed two irreversible reduction waves for its H₂bzimpy ligands at -1.593V and -1.978V, respectively. The two maxima of adsorption of the complex in acetonitrile occur respectively at 308nm and 345nm, and that of adsorption of it in DMF does at 334nm. That of emission of the complex in acetonitrile occurs at 443nm.The cyclic voltammogram of the complex [Co(5-NO2-phen)2 dppz]3+ have shown a quasi-reversible Co(III)/Co( II) redox couple at 0.567V vs SCE, and a irreversible Co(II)/Co(0) reduction reaction at -0.551V vs SCE. The five maxima of adsorption of the complex inCH3OH occur respectively at 232, 271, 341, 357nm and 375nm, and those of emission of the complex in CHsOH occur at 476nm and 538nm, respectively.The interaction of the complexes [Co(H2bzimpy)2](CIO₄)2 and [Co(5-NO2-phen)2dppz](ClO4)₃ with DNA have been studied by absorption spectra and fluorescence spectra. The results indicate that both of the new polypyridly cobalt complexes interact with DNA by intercalative binding.