Oliveri Christopher G, Ulmann Pirmin A, Wiester Michael J, Mirkin Chad A
Department of Chemistry and the International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, USA.
Acc Chem Res. 2008 Dec;41(12):1618-29. doi: 10.1021/ar800025w.
Supramolecular coordination chemistry allows researchers to synthesize higher-order structures that approach the nanoscale dimensions of small enzymes. Frequently, such structures have highly symmetric macrocyclic square or cage shapes. To build functional structures that mimic the complex recognition, catalytic, and allosteric properties of enzymes, researchers must do more than synthesize highly symmetric nanoscale structures. They must also simultaneously incorporate different functionalities into these structures and learn how to regulate their relative arrangement with respect to each other. Designing such heteroligated coordination complexes remains a significant challenge for supramolecular chemists. This Account focuses on the discovery and development of a novel supramolecular reaction known as the halide-induced ligand rearrangement (HILR) reaction. Two hemilabile ligands with different binding strengths combine with d(8) transition metal precursors that contain halide ions. The reaction spontaneously results in heteroligated complexes and is highly modular and general. Indeed, it not only can be used to prepare tweezer complexes but also allows for the rapid and quantitative formation of heteroligated macrocyclic triple-decker/step and rectangular box complexes from a variety of different ligands and transition metal ions. The relative arrangement between functional groups A and B in these structures can be regulated in situ using small ancillary ligands such as halides, CO, and nitriles. Based on this reaction, zinc- and magnesium-porphyrin moieties can be incorporated into heteroligated macrocyclic or tweezer scaffolds. These examples demonstrate the convergent and cofacial assembly of functional sites that are known to be involved in numerous processes in enzymes. They also show how the relative spatial and lateral distances of these sites can be varied, in many cases reversibly. Researchers can use such complexes to study a wide range of enzymatic processes, including catalysis, molecular recognition, electron transfer, and allosteric signal transfer.
超分子配位化学使研究人员能够合成接近小型酶纳米尺度尺寸的高阶结构。通常，此类结构具有高度对称的大环方形或笼状形状。为了构建模仿酶的复杂识别、催化和变构特性的功能结构，研究人员必须做的不仅仅是合成高度对称的纳米尺度结构。他们还必须同时将不同的功能基团纳入这些结构中，并了解如何调节它们彼此之间的相对排列。设计此类杂配配位络合物对超分子化学家来说仍然是一项重大挑战。本综述重点介绍了一种新型超分子反应——卤化物诱导的配体重排（HILR）反应的发现和发展。两种具有不同结合强度的半不稳定配体与含有卤离子的d(8)过渡金属前体相结合。该反应自发产生杂配络合物，且具有高度的模块化和通用性。实际上，它不仅可用于制备镊子状络合物，还能使各种不同的配体和过渡金属离子快速定量地形成杂配大环三层/阶梯状和矩形盒状络合物。这些结构中官能团A和B之间的相对排列可使用卤化物、CO和腈等小辅助配体原位调节。基于此反应，锌卟啉和镁卟啉部分可被纳入杂配大环或镊子状支架中。这些例子展示了已知参与酶中众多过程的功能位点的汇聚和共面组装。它们还展示了这些位点的相对空间和横向距离在许多情况下如何变化，且在很多情况下是可逆的。研究人员可以使用此类络合物来研究广泛的酶促过程，包括催化、分子识别、电子转移和变构信号传递。
