Department of Chemistry, UMR 8640 CNRS-ENS-UPMC, Ecole Normale Supérieure, 24 rue Lhomond, 75005 Paris, France.
Dalton Trans. 2012 Dec 21;41(47):14257-64. doi: 10.1039/c2dt31830j.
This paper describes a new series of organometallic water-soluble chelators combining a redox moiety (ferrocene) and a selective Ca2+ chelator (BAPTA) separated by an ethynyl bridge. We report the synthesis and characterization of organometallic derivatives of the BAPTA chelator featuring one (2a) and two ferrocenyl (2b) moieties. Single crystal X-ray structural analysis on these chelators revealed unexpected conformations for the ferrocenyl substituent with respect to the phenyl ring of the BAPTA unit. DFT calculations on a model system of the ferrocenyl-ethynyl-BAPTA molecule were carried out to evaluate the energy separation between the two limiting conformations observed experimentally in the solid state, and to check the effective electronic communication between the binding pocket and the redox probe. The binding affinity of 2a–b for Ca2+, as probed by UV-Vis and cyclic voltammetry, revealed distinct behaviors in the presence of a metal ion depending on whether BAPTA is substituted by one or two ferrocenyl groups.
本文描述了一系列新的有机金属水溶性螯合剂，它们结合了一个氧化还原部分（二茂铁）和一个选择性的 Ca2+ 螯合剂（BAPTA），由乙炔桥隔开。我们报告了 BAPTA 螯合剂的有机金属衍生物的合成和表征，这些衍生物具有一个（2a）和两个二茂铁（2b）部分。对这些螯合剂的单晶 X 射线结构分析显示，相对于 BAPTA 单元的苯基环，二茂铁取代基具有意想不到的构象。对二茂铁-乙炔基-BAPTA 分子模型体系进行了 DFT 计算，以评估在固态实验中观察到的两种极限构象之间的能量分离，并检查结合口袋和氧化还原探针之间的有效电子通讯。紫外可见和循环伏安法探测 2a-b 对 Ca2+ 的结合亲和力，在存在金属离子时，根据 BAPTA 是否被一个或两个二茂铁基团取代，表现出明显不同的行为。
