Kekulé-Institut für Organische Chemie und Biochemie, Rheinische Friedrich-Wilhelms-Universität Bonn, Gerhard-Domagk-Strasse1, 53121, Bonn, Germany.
Department of Chemistry, University of Jyväskylä, P.O. Box 35, 40014, Jyväskylä, Finland.
Chemistry. 2019 Sep 20;25(53):12294-12297. doi: 10.1002/chem.201903164. Epub 2019 Aug 28.
An enantiomerically pure diamine based on the 4,15-difunctionalized [2.2]paracyclophane scaffold and 2-formylpyridine self-assemble into an optically pure cyclic metallosupramolecular Fe L helicate upon mixing with iron(II) ions in a diastereoselective subcomponent self-assembly process. The cyclic assembly results from steric strain that prevents the formation of a smaller linear dinuclear triple-stranded helicate, and hence, leads to the larger strain-free assembly that fulfils the maximum occupancy rule. Interestingly, use of the racemic diamine also leads to a racemic mixture of the homochiral cyclic helicates as the major product in a highly diastereoselective narcissistic chiral self-sorting manner given the fact that the assembly contains ten stereogenic elements, which can in principle give rise to 149 different diastereomers. The metallosupramolecular aggregates could be characterized by NMR, UV/Vis and CD spectroscopy, mass spectrometry, and X-ray crystallography.
基于 4,15-双官能化[2.2]对环芳烷骨架和 2-糠醛吡啶的对映体纯二胺在与铁(II)离子混合时，通过非对映选择性亚组分自组装，自组装成光学纯的环状金属超分子 Fe L 螺旋。环状组装是由空间应变引起的，空间应变阻止了较小的线性双核三链螺旋的形成，因此导致了更大的无应变组装，从而满足了最大占据规则。有趣的是，即使使用外消旋二胺，也会以高度非对映选择性的自恋手性自分拣方式得到外消旋混合物的同手性环状螺旋，因为组装体包含十个立体中心，理论上可以产生 149 种不同的非对映异构体。金属超分子聚集体可以通过 NMR、UV/Vis 和 CD 光谱、质谱和 X 射线晶体学进行表征。
