Department of Chemistry, University of Pittsburgh , Pittsburgh, Pennsylvania 15260, United States.
Department of Chemistry, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States.
J Am Chem Soc. 2016 Sep 21;138(37):12045-8. doi: 10.1021/jacs.6b07445. Epub 2016 Sep 9.
Crystalline 3-D materials bearing interlinked domains of differential porosity and functionality offer the potential for organizing and shuttling molecular and nanoscale matter to specific locations within 3-D space. Here, we present methods for creating prototype MOF materials that have such structural features. Specifically, the process of pore expansion via ligand exchange was studied for an isoreticular series of mesoporous MOFs based on bMOF-100. It was found that pore expansion occurs incrementally in small steps and that it proceeds gradually in an "outside→in" fashion within individual crystals. The ligand exchange reaction can be terminated prior to complete crystal conversion to yield intermediate product MOFs, denoted bMOF-100/102 and bMOF-102/106, which bear descending porosity gradients from the crystal periphery to the crystal core. As a proof of concept, size-sensitive incorporation of a gold-thiolate nanocluster, Au133(SR)52, selectively in the bMOF-102/106 crystal periphery region was accomplished via cation exchange. These new methods open up the possibility of controlling molecular organization and transport within porous MOF materials.
具有互连成畴的不同孔隙率和功能的晶体 3-D 材料为将分子和纳米级物质组织并输送到 3-D 空间的特定位置提供了可能性。在这里，我们提出了创建具有此类结构特征的原型 MOF 材料的方法。具体来说，通过配体交换研究了一系列基于 bMOF-100 的中孔 MOF 的孔扩张过程。结果发现，孔扩张以小步逐渐进行，并且在单个晶体中以“从外到内”的方式逐渐进行。可以在完全转化之前终止配体交换反应，以生成中间产物 MOF，分别表示为 bMOF-100/102 和 bMOF-102/106，它们具有从晶体边缘到晶体核心的下降孔隙梯度。作为概念验证，通过阳离子交换，在 bMOF-102/106 晶体边缘区域选择性地掺入了尺寸敏感的金-硫醇纳米团簇 Au133(SR)52。这些新方法为控制多孔 MOF 材料中的分子组织和输运提供了可能性。
