Synthesis, Characterization, and X-ray Crystal Structures of Cyclam Derivatives. 8. Thermodynamic and Kinetic Appraisal of Lead(II) Chelation by Octadentate Carbamoyl-Armed Macrocycles<sup>1</sup>
作者:François Cuenot、Michel Meyer、Enrique Espinosa、Roger Guilard
DOI:10.1021/ic0508019
日期:2005.10.1
En route toward the development of hybrid organic-inorganic extracting materials incorporating lead-selective chelators and their implementation in water purification processes, the lead(II) binding properties of three N-carbamoylmethyl-substituted 1,4,8,11-tetraazacyclotetradecanes (cyclams) have been fully investigated by spectroscopic (IR, UV-vis, MALDI-TOF MS, (1)H and (13)C NMR), X-ray crystallographic
在开发包含铅选择性螯合剂的杂化有机-无机萃取材料及其在水净化过程中的应用的过程中,三种N-氨基甲酰基甲基取代的1,4,8,11-四氮杂环十四烷(环酰胺)的铅(II)结合特性)已通过光谱法(IR,UV-vis,MALDI-TOF MS,(1)H和(13)C NMR),X射线晶体学,电位法和动力学方法进行了充分研究。溶液NMR研究表明,Pb(2+)离子被截留在由四个大环氮和四个酰胺氧原子组成的分子笼中。在水溶液中测定的质子化和铅结合常数显示出线性依赖性,因此所有三种衍生物在任何pH值下均具有相似的亲和力。热力学和动力学参数揭示了分子内氢键也发挥了关键作用,四乙酰胺衍生物L(1)的晶体结构也证明了这一点,该结构涉及每个大环叔胺的孤对和一个属于附加臂的酰胺氢原子。与L(1)相比,对于N-(二甲基)氨基甲酰基甲基-和N-(二乙基)氨基甲酰基甲基取代的cyclams(分别为L(2)和L(3)),没有这