Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge CB2 1EW, United Kingdom.
J Am Chem Soc. 2015 Feb 11;137(5):1770-3. doi: 10.1021/ja5120437. Epub 2015 Feb 2.
In order to design artificial chemical systems that are capable of achieving complex functions, it is useful to design synthetic receptors that mimic their biological counterparts. Biological functions are underpinned by properties that include specific binding with high affinity and selectivity, cooperativity, and release triggered by external stimuli. Here we show that a metal-organic receptor constructed through subcomponent self-assembly can selectively and cooperatively load and release oxocarbon anions. The flexible coordination spheres of its cadmium(II) centers allow the receptor to dynamically adjust its structure upon exchanging four triflate or triflimide counterions for two oxocarbon anions, resulting in strong cooperativity and very tight binding, with an apparent association constant for C5O5(2-) of 5 × 10(10) M(-1). Substituting the cadmium(II) ions for copper(I) by switching solvent prompted a structural reorganization and release of the oxocarbon anions. Its cooperative behavior allows the receptor to carry a greater payload than would be possible in a noncooperative analogue.
为了设计能够实现复杂功能的人工化学系统，设计模拟其生物对应物的合成受体是很有用的。生物功能的基础是包括特异性高亲和力和选择性结合、协同作用以及外部刺激触发释放在内的特性。在这里，我们展示了通过亚组件自组装构建的金属有机受体可以选择性和协同地负载和释放氧碳阴离子。其镉（II）中心的灵活配位球允许受体在将四个三氟甲磺酸根或三氟甲磺酰亚胺阴离子交换为两个氧碳阴离子时动态调整其结构，从而导致强协同作用和非常紧密的结合，对于 C5O5(2-) 的表观缔合常数为 5 × 10(10) M(-1)。通过切换溶剂将镉（II）离子替换为铜（I）离子会促使结构重新组织并释放氧碳阴离子。其协同行为允许受体携带比非协同类似物更多的有效载荷。
