A Definitive Example of a Geometric “Entatic State” Effect: Electron-Transfer Kinetics for a Copper(II/I) Complex Involving A Quinquedentate Macrocyclic Trithiaether−Bipyridine Ligand
作者:Gezahegn Chaka、Jason L. Sonnenberg、H. Bernhard Schlegel、Mary Jane Heeg、Gregory Jaeger、Timothy J. Nelson、L. A. Ochrymowycz、D. B. Rorabacher
DOI:10.1021/ja068960u
日期:2007.4.1
([15]aneS3bpy = L), containing two pyridyl nitrogens and three thiaether sulfurs as donor atoms, has been synthesized and complexed with copper. The CuII/IL redox potential, the stabilities of the oxidized and reduced complex, and the oxidation and reduction electron-transfer kinetics of the complex reacting with a series of six counter reagents have been studied in acetonitrile at 25 degrees C, mu = 0.10 M (NaClO4)
五齿大环配体环-6,6'-[1,9-(2,5,8-trithianonane)]-2,2'-联吡啶 ([15]aneS3bpy = L),含有两个吡啶基氮和三个硫醚硫作为供体原子,已被合成并与铜络合。CuII/IL 氧化还原电位、氧化和还原配合物的稳定性,以及配合物与一系列六种相反试剂反应的氧化和还原电子转移动力学在乙腈中进行了研究,温度为 25 摄氏度,μ = 0.10 M (NaClO4)。马库斯交叉关系已应用于与六种反试剂中的每一种反应获得的速率常数,以允许评估电子自交换速率常数 k11。后一个值也已独立于 NMR 谱线加宽实验确定。累积数据与 k11 = 1 x 10(5) M(-1) s(-1) 的值一致,将其列为反应最快的 CuII/I 系统,与称为铜氧还蛋白。解析的晶体结构表明,CuIIL 和 CuIL 复合物的几何形状几乎相同,两者都表现出五坐标方形金字塔几何形状,中心硫供体原子占据顶端位置。最显着的几何差异是