Department of Chemistry, Northwestern University, Evanston, IL 60208, USA.
Chemical and Biological Engineering Department, Colorado School of Mines, Golden, CO 80401, USA.
Science. 2017 May 12;356(6338):624-627. doi: 10.1126/science.aam7851. Epub 2017 Apr 20.
Bottom-up construction of highly intricate structures from simple building blocks remains one of the most difficult challenges in chemistry. We report a structurally complex, mesoporous uranium-based metal-organic framework (MOF) made from simple starting components. The structure comprises 10 uranium nodes and seven tricarboxylate ligands (both crystallographically nonequivalent), resulting in a 173.3-angstrom cubic unit cell enclosing 816 uranium nodes and 816 organic linkers-the largest unit cell found to date for any nonbiological material. The cuboctahedra organize into pentagonal and hexagonal prismatic secondary structures, which then form tetrahedral and diamond quaternary topologies with unprecedented complexity. This packing results in the formation of colossal icosidodecahedral and rectified hexakaidecahedral cavities with internal diameters of 5.0 nanometers and 6.2 nanometers, respectively-ultimately giving rise to the lowest-density MOF reported to date.
从简单的构建块自下而上构建高度复杂的结构仍然是化学领域最具挑战性的难题之一。我们报道了一种结构复杂的介孔铀基金属有机骨架（MOF），它由简单的起始组件制成。该结构由 10 个铀节点和 7 个三羧酸配体（均在晶体学上不等同）组成，形成一个 173.3 埃的立方单元，其中包含 816 个铀节点和 816 个有机连接体——这是迄今为止发现的任何非生物材料中最大的单元。立方八面体组织成五边形和六边形的棱柱形二级结构，然后形成具有前所未有的复杂性的四面体和钻石四元拓扑结构。这种堆积导致形成巨大的 icosidodecahedral 和 rectified hexakaidecahedral 空腔，内部直径分别为 5.0 纳米和 6.2 纳米——最终产生了迄今为止报道的密度最低的 MOF。
