Cyclometalated iridium(III) complex of 6‐hydroxydipyrido[3,2‐a:2′,3′‐c]phenazine: synthesis,and acid–base and avid DNA binding properties |
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Authors: | Yan‐Min Chen An‐Guo Zhang Ke‐Zhi Wang |
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Institution: | College of Chemistry, Beijing Normal University, Beijing 100875, China |
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Abstract: | A new cyclometalated Ir(III) complex Ir(ppy)2(hdppz)]PF6 (Hppy = 2‐phenylpyridine and hdppz = 6‐hydroxydipyrido3,2‐a:2′,3′‐c]phenazine) was synthesized and characterized. The pH effects on the UV–vis absorption spectra were studied and ground‐state acid ionization constant pKa values of the complex were derived. The calf thymus DNA (ct‐DNA) binding properties of the complex were investigated with UV‐vis absorption spectrophotometric titrations, DNA competitive binding with ethidium bromide, DNA melting experiments, viscosity measurements and density functional theory (DFT) calculations. The complex was demonstrated to act as a ct‐DNA intercalator with a large DNA binding constant value of (6.06 ± 0.32) × 106 M ?1 in 50 mM NaCl. The avid DNA binding affinity observed was rationalized by the DFT calculations. Copyright © 2011 John Wiley & Sons, Ltd. |
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Keywords: | iridium pH DNA spectroscopy |
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