Self-Assembly of Chiral Metal–Organic Tetartoid

Chiral coordination cages feature both chirality and defined inner space, providing advanced molecular materials. A series of chiral 20-nucleus cobalt-imidazolate cages were synthesized by self-assembly of 72 subcomponents, featuring a novel tetartoid (tetragonal pentagonal dodecahedron) structure. Spontaneous resolution of racemic tetartoidal cages (Δ and Λ) into a conglomerate of homochiral crystals are observed, while both homochiral Δ and Λ tetartoidal cages can be obtained through chiral induction of (d)- and (l)-enantiomers of menthol, respectively. The 2-methyl substituent on imidazolyl is critical to the formation of a tetartoidal cage, and the absence of such steric effect will switch the final structure to a cubic cage.手性配位笼（chiral coordination cage）兼具手性与规整的内部空腔，是一类先进分子材料。本研究通过72个亚组分的自组装反应，合成了一系列手性20核钴咪唑酸盐配位笼，其具有新颖的四分面体（tetartoid，四方五边形十二面体）结构。实验观测到外消旋四分面体笼（Δ与Λ构型）可自发拆分为均手性晶体的聚集体；同时分别借助（d）-与（l）-薄荷醇对映体的手性诱导，可获得均手性Δ型与Λ型四分面体笼。咪唑基上的2-甲基取代基对四分面体笼的形成至关重要，若缺失该空间位阻效应，最终产物的结构将转变为立方笼。