Benchimol Elie, Regeni Irene, Zhang Bo, Kabiri Michele, Holstein Julian J, Clever Guido H
Department of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn Str. 6, Dortmund 44227, Germany.
J Am Chem Soc. 2024 Mar 13;146(10):6905-6911. doi: 10.1021/jacs.3c14168. Epub 2024 Feb 29.
Heteroleptic coordination cages, nonstatistically assembled from a set of matching ligands, can be obtained by mixing individual components or via cage-to-cage transformations from homoleptic precursors. Based on the latter approach, we here describe a new level of self-sorting in coordination cage systems, namely, 'heteromeric completive self-sorting'. Here, two heteroleptic assemblies of type PdAB and PdAC, sharing one common ligand component A but differing in the other, are shown to coexist in solution. This level of self-sorting can be reached either from a statistical mixture of assemblies based on some ligands B and C or, alternatively, following a first step of integrative self-sorting giving a distinct PdBC intermediate. While subtle enthalpic factors dictate the outcome of the self-sorting, we found that it is controllable. From a unique set of three ligands, we demonstrate the transition from strict integrative self-sorting forming a PdABC cage to heteromeric completive self-sorting to give PdAB and PdAC by variation of the ligand ratio. Cage-to-cage transformations were followed by NMR and MS experiments. Single crystal X-ray structures for three new heteroleptic cages were obtained, impressively highlighting the versatility of ligand A to either form a π-stacked -figure-of-eight arrangement in PdAB or occupy two -edges in PdAC or only a single edge in PdABC. This study paves the way toward the control of heteroleptic cage populations in a systems chemistry context with emerging features such as chemical information processing, adaptive guest selectivity, or stimuli-responsive catalytic action.
通过混合单个组分或经由同配体前体的笼间转化，可以得到由一组匹配配体非统计组装而成的杂配体配位笼。基于后一种方法，我们在此描述了配位笼系统中一种新的自分类水平，即“异聚竞争性自分类”。在此，两种类型为PdAB和PdAC的杂配体组装体，共享一个共同的配体组分A但另一个不同，被证明在溶液中共存。这种自分类水平可以从基于一些配体B和C的组装体的统计混合物中达到，或者，在第一步整合自分类产生一个独特的PdBC中间体之后达到。虽然微妙的焓因素决定了自分类的结果，但我们发现它是可控的。从一组独特的三种配体中，我们通过改变配体比例展示了从形成PdABC笼的严格整合自分类到产生PdAB和PdAC的异聚竞争性自分类的转变。通过核磁共振和质谱实验跟踪笼间转化。获得了三种新的杂配体笼的单晶X射线结构，令人印象深刻地突出了配体A的多功能性，它可以在PdAB中形成π堆积的八字形排列，或者在PdAC中占据两条边，或者在PdABC中只占据一条边。这项研究为在系统化学背景下控制杂配体笼的种群铺平了道路，具有诸如化学信息处理、自适应客体选择性或刺激响应催化作用等新出现的特征。
