Gheorghe Andreea, Imaz Inhar, van der Vlugt Jarl Ivar, Maspoch Daniel, Tanase Stefania
Heterogeneous Catalysis and Sustainable Chemistry, Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands.
Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and Barcelona Institute of Science and Technology, Campus UAB, Bellaterra 08193, Barcelona, Spain.
Dalton Trans. 2019 Jul 21;48(27):10043-10050. doi: 10.1039/c9dt01572h. Epub 2019 Jun 7.
Supramolecular isomerism of metal-organic frameworks (MOFs) is known for several MOF structures, having direct implications on the properties of these materials. Although the synthesis of MOF isomers is mainly serendipitous in nature, achieving controlled formation of a target framework is highly relevant for practical applications. This work discusses the influence of additives and synthesis conditions on the formation of porous isomers containing Zn as nodes and 2,5-dihydroxy-1,4-benzenedicarboxylate (dobdc) as a linker. Using solvent mixtures containing strongly coordinated molecules, e.g. N,N'-dimethylformamide (DMF) and N-methylpyrrolidone (NMP), facilitates the formation of porous structures of type [Zn(dobdc)(S)]·yS (S = DMF, NMP) which are built from dinuclear Zn(O)(CO) secondary building units (SBUs) consisting of two different edge-sharing polyhedra with the Zn ions in a unsaturated coordinative environment. In the presence of water, the Zn dimers are converted to one-dimensional infinite Zn chains, in which the number of Zn-linker bonds increases, therefore giving a hydrolytically more stable coordination environment. The full characterization of the isomers as well as their conversion to the most stable isomer is presented.
金属有机框架（MOF）的超分子异构现象在几种MOF结构中是已知的，这对这些材料的性质有直接影响。尽管MOF异构体的合成本质上主要是偶然的，但实现目标框架的可控形成对于实际应用非常重要。这项工作讨论了添加剂和合成条件对以锌为节点、2,5-二羟基-1,4-苯二甲酸酯（dobdc）为连接体的多孔异构体形成的影响。使用含有强配位分子的溶剂混合物，例如N,N'-二甲基甲酰胺（DMF）和N-甲基吡咯烷酮（NMP），有助于形成[Zn(dobdc)(S)]·yS型（S = DMF，NMP）的多孔结构，这些结构由双核Zn(O)(CO)二级结构单元（SBU）构建而成，该二级结构单元由两个不同的共边多面体组成，锌离子处于不饱和配位环境中。在水存在的情况下，锌二聚体转变为一维无限锌链，其中锌-连接体键的数量增加，因此提供了水解稳定性更高的配位环境。本文介绍了异构体的全面表征以及它们向最稳定异构体的转化。
