Department of Chemistry, University of South Florida, 4202 East Fowler Avenue (CHE205), Tampa, Florida 33620, USA.
J Am Chem Soc. 2009 Mar 4;131(8):2864-70. doi: 10.1021/ja807229a.
Zeolite-like metal-organic frameworks (ZMOFs) are anionic, have readily exchangeable extra-framework cations, and can be constructed with a variety of organic linkers. ZMOFs therefore can be regarded as an excellent platform for systematic studies of the effect(s) of various structural factors on H(2) binding/interaction with porous metal-organic materials. We find that the enhanced binding of molecular hydrogen in ion-exchanged ZMOFs with an anionic framework is largely governed by the presence of the electrostatic field in the cavity, which is reflected by isosteric heats of adsorption in these compounds which are greater by as much as 50% relative to those in neutral MOFs. Direct contact of the sorbed hydrogen with the exchangeable cations is shown not to be possible in the explored systems thus far, as they retain their form as aqua complexes.
沸石样金属有机骨架（ZMOFs）为阴离子型，具有可交换的额外骨架阳离子，且可利用多种有机配体进行构建。因此，ZMOFs 可被视为系统研究各种结构因素对多孔金属有机材料中 H(2)结合/相互作用影响的绝佳平台。我们发现，在带负电骨架的离子交换 ZMOFs 中，分子氢的增强结合主要由腔内静电场的存在决定，这反映在这些化合物的吸附等焓上，其比中性 MOFs 高出多达 50%。迄今为止，在所研究的体系中，被吸附的氢与可交换阳离子之间不可能直接接触，因为它们仍以水合配合物的形式存在。
