Investigating the copper coordination, electrochemistry, and Cu(ii) reduction kinetics of biologically relevant selone and thione compounds
作者:Martin M. Kimani、Hsiao C. Wang、Julia L. Brumaghim
DOI:10.1039/c2dt11731b
日期:——
Selenium- and sulfur-containing compounds can act as antioxidants by binding copper. To determine how this copper coordination results in the observed antioxidant activity, biologically relevant Cu+ and Cu2+ complexes with the formulae [Cu(dmit)3]+ (3), [Cu(dmise)4]+ (4a), and [TpmiPrCu(MISeox)]2+ (6) (dmise = N,N′-dimethylimidazole selone; dmit = N,N′-dimethylimidazole thione; MISeox = bis(1-methylimidazolyl)diselenide; TpmiPr = tris(1,3-diisopropylpyrazolyl)methane) were synthesized, characterized, and their structures determined by single-crystal X-ray crystallography. In addition, kinetic studies using UV-vis spectroscopy indicate that dmise reduces Cu2+ to Cu+ three times faster than dmit. Coordination of dmise and MISeox to copper also results in more negative Cu2+/+ reduction potentials (−373 mV and −503 mV) compared to dmit (−217 mV). These results highlight the different complexation behaviors and reactivities of analogous selone- and thione-containing compounds, traits which likely influence their antioxidant activity.
含硒和硫的化合物可以通过结合铜来作为抗氧化剂。为了确定这种铜配位是如何导致观察到的抗氧化活性的,合成并表征了生物相关的Cu+和Cu2+配合物,其化学式为[Cu(dmit)3]+ (3),[Cu(dmise)4]+ (4a),以及[TpmiPrCu(MISeox)]2+ (6) (dmise = N,N′-二甲基咪唑硒;dmit = N,N′-二甲基咪唑硫;MISeox = 双(1-甲基咪唑基)二硒化物;TpmiPr = 三(1,3-二异丙基吡唑基)甲烷),并通过单晶X射线衍射确定了它们的结构。此外,使用紫外-可见光谱的动力学研究表明,dmise将Cu2+还原为Cu+的速度是dmit的三倍。dmise和MISeox与铜的配位也导致更负的Cu2+/+还原电位(分别为−373 mV和−503 mV),而dmit的还原电位为(−217 mV)。这些结果突显了类似硒化物和硫化物化合物在络合行为和反应性方面的不同特性,这些特性可能影响它们的抗氧化活性。