Fluorescence and phosphorescence spectra of Au(III), Pt(II) and Pd(II) porphyrins with DNA at room temperature
Fluorescence and phosphorescence spectra of Au(III), Pt(II) and Pd(II) porphyrins with DNA at room temperature
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DOI：
10.1016/j.ica.2003.08.023
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发表时间：
2004-02
影响因子：
2.8
通讯作者：
Elvis Nyarko;Nami Hanada;Ahsan Habib;M. Tabata
中科院分区：
文献类型：
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作者：
Elvis Nyarko;Nami Hanada;Ahsan Habib;M. Tabata
在0.1 M NaCl、pH 7.5和25 °C条件下，研究了四（1-甲基吡啶-4基）卟啉（H2（TMPyP）4+）的Au（III）、Pt（II）和Pd（II）衍生物与pBluescriptII质粒DNA的相互作用。游离碱卟啉（H2（TMPyP）4+）、Au（III）（TMPyP）5+和Pt（II）（TMPyP）4+发射荧光。另一方面，Pd（II）（TMPyP）4+在室温下发射荧光和磷光。当加入过量的DNA时，H2（TMPyP）4+和Au（III）（TMPyP）5+的宽荧光光谱变为两个清晰的峰，H2（TMPyP）4+的峰中心分别为650和710 nm，Au（III）（TMPyP）5+的峰中心分别为659.2和719.6 nm。然而，Pt（II）（TMPyP）4+的荧光强度随着加入大量DNA而增加，在660 nm处产生具有肩峰的峰。有趣的是，对于Pd（II）（TMPyP）4+，观察到在增加量的DNA存在下，在700 nm处观察到的磷光强度增加。为了确认卟啉的化学种类（即单体或二聚体），还在不同浓度的NaCl（0.001- 0.1M）和乙醇（0- 40%v/v）下测量了这些卟啉的荧光和磷光光谱。这些目前的数据与以前的研究表明，H2（TMPyP）4+和Au（III）（TMPyP）5+在水溶液中显示聚集体，Pt（II）（TMPyP）4+部分聚集体，它们通过嵌入或外部结合DNA转化为单体形式。观察到的Pd（II）（TMPyP）4+的弱磷光强度通过加入大量DNA而增加，这是由于DNA屏蔽了插入的卟啉，这防止了它与溶解在水中的分子氧反应。UV-Vis和CD结果表明，Pt（II）（TMPyP）4+和Pd（II）（TMPyP）4+与H2（TMPyP）4+一样嵌入DNA碱基中，而Au（III）（TMPyP）5+与DNA以外侧结合方式结合，但在高浓度时有部分嵌入。
The fluorescence and phosphorescence studies on the interactions of Au(III), Pt(II) and Pd(II) derivatives of tetrakis(1-methylpyridinium-4yl)porphyrin (H2(TMPyP)4+) with pBluescript II plasmid DNA have been conducted at 0.1 M NaCl, pH 7.5 and 25 °C. The free base porphyrin (H2(TMPyP)4+), Au(III)(TMPyP)5+and Pt(II)(TMPyP)4+emitted fluorescence. On the other hand, the Pd(II)(TMPyP)4+emitted both fluorescence and phosphorescence at room temperature. Upon the addition of excess amounts of DNA the broad fluorescence spectra of H2(TMPyP)4+and Au(III)(TMPyP)5+changed to two clear peaks centred at 650 and 710 nm for H2(TMPyP)4+, and 659.2 and 719.6 nm for Au(III)(TMPyP)5+, respectively. However, the fluorescence intensity of the Pt(II)(TMPyP)4+increased with addition of high amounts of DNA, giving a peak at 660 nm with a shoulder. Interestingly for Pd(II)(TMPyP)4+, it was observed that in the presence of increasing amounts of DNA, the phosphorescence intensity observed at 700 nm increased. In order to confirm the chemical species of the porphyrins (that is monomer or dimer) the fluorescence and phosphorescence spectra of these porphyrins were also measured at different concentrations of NaCl (0.001–0.1 M) and ethanol (0–40% v/v). Comparison of these current data to previous studies suggests that H2(TMPyP)4+and Au(III)(TMPyP)5+show aggregates in aqueous solution, Pt(II)(TMPyP)4+partially aggregates, and they become converted to the monomer form by intercalation or outside binding to DNA. The weak phosphorescence intensity observed for Pd(II)(TMPyP)4+that was increased by the addition of large amounts of DNA is due to shielding of the intercalated porphyrin by the DNA which prevents it from reacting with molecular oxygen dissolved in water. The UV–Vis and CD results indicate that, like H2(TMPyP)4+, Pt(II)(TMPyP)4+and Pd(II)(TMPyP)4+intercalate into the DNA bases while Au(III)(TMPyP)5+interacts with DNA via the out-side binding mode but with partial intercalation at high concentrations.