Abstract

The rational reticular design of metal—organic frameworks (MOFs) from building units of known geometries is essential for enriching the diversity of MOF structures. Unexpected and intriguing structures, however, can also arise from subtle changes in the rigidity/length of organic linkers and/or synthetic conditions. Herein, we report three uranium-based MOF structures—i.e., NU-135X (X = 0, 1, 2)—synthesized from trigonal planar uranyl nodes and triptycene-based hexacarboxylate ligands with variable arm lengths. A new chiral 3,6-connected nuc net was observed in NU-1350, while the extended versions of the ligand led to 3-fold catenated MOFs (NU-1351 and NU-1352) with rare 3,6-connected cml-c3 nets. The differences in the topology of NU-1350 and NU-1351/NU-1352 could be attributed to the slight distortions of the shorter linker in the former from the ideal trigonal prism geometry to an octahedral geometry when coordinated to the trigonal planar uranyl nodes.

中文翻译：

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带六羧酸盐建筑单元的铀基金属有机框架的网状勘探

摘要

由已知几何形状的建筑单元对金属有机框架（MOF）进行合理的网状设计对于丰富MOF结构的多样性至关重要。然而，有机连接物的刚性/长度和/或合成条件的细微变化也可能引起意想不到的有趣结构。在这里，我们报道了由三角形平面铀酰节点和具有可变臂长的基于三茂铁的六羧酸酯配体合成的三个基于铀的MOF结构，即NU-135X（X = 0、1、2）。在NU-1350中观察到一个新的手性3,6-连接的nuc网络，而配体的扩展版本导致3折叠的MOF（NU-1351和NU-1352）带有罕见的3,6-连接的cml-c3网。NU-1350和NU-1351 / NU-1352的拓扑结构差异可能是由于前者中较短的连接子与理想的三角棱柱几何形状协调成三角平面的铀酰基团时从理想的三角棱柱几何形状略微变形。