Poul Nicolas Le, Campion Morgan, Douziech Bénédicte, Rondelez Yannick, Clainche Loïc Le, Reinaud Olivia, Mest Yves Le
Laboratoire de Chimie, Electrochimie Moléculaires et Chimie Analytique, UMR CNRS 6521, Université de Bretagne Occidentale, CS 93837, 6 avenue Le Gorgeu, 29238 Brest cedex 3, France.
J Am Chem Soc. 2007 Jul 18;129(28):8801-10. doi: 10.1021/ja071219h. Epub 2007 Jun 20.
The electrochemical behavior of diversely substituted Cu-N3-calix[6]arene, enzyme-like, "funnel" complexes is analyzed. The Cu(II)/Cu(I) redox process is regulated by the supramolecular organization of the Cu coordination. The presence of a "shoetree" alkyl nitrile guest molecule inside the host cavity is a prerequisite for a dynamic redox behavior. Combination of supramolecular CH-pi weak interactions with the calixarene cavity and electronic/steric effects from the N3 substituting groups (pyridine, imidazole, pyrrolidine) enforces the preferential geometrical pattern adopted by Cu. This dictates the pathway of the electron-transfer process and, thus, the thermodynamics and kinetics of the redox reaction in the framework of a square-scheme mechanism. The present observations recall strongly the redox control exerted by the protein matrix on copper proteins through biological concepts such as induced fit mechanism, protein foldings, and entatic and allosteric effects.
分析了不同取代的 Cu-N3-杯[6]芳烃类酶“漏斗”配合物的电化学行为。Cu(II)/Cu(I)氧化还原过程受 Cu 配位的超分子组织调控。主体腔内存在“鞋架”烷基腈客体分子是动态氧化还原行为的先决条件。杯芳烃腔的超分子 CH-π 弱相互作用与 N3 取代基（吡啶、咪唑、吡咯烷）的电子/空间效应相结合，强化了 Cu 所采用的优先几何构型。这决定了电子转移过程的途径，进而决定了方形机制框架内氧化还原反应的热力学和动力学。目前的观察结果强烈让人联想到蛋白质基质通过诱导契合机制、蛋白质折叠以及内稳态和变构效应等生物学概念对铜蛋白施加的氧化还原控制。
