Zhai Quan-Guo, Bai Ni, Li Shu'ni, Bu Xianhui, Feng Pingyun
Department of Chemistry, University of California , Riverside, California 92521, United States.
School of Chemistry & Chemical Engineering, Shaanxi Normal University , Xi'an, Shaanxi 710062, People's Republic of China.
Inorg Chem. 2015 Oct 19;54(20):9862-8. doi: 10.1021/acs.inorgchem.5b01611. Epub 2015 Oct 2.
In the design of new materials, those with rare and exceptional compositional and structural features are often highly valued and sought after. On the other hand, materials with common and more accessible modes can often provide richer and unsurpassed compositional and structural variety that makes them a more suitable platform for systematically probing the composition-structure-property correlation. We focus here on one such class of materials, pillar-layered metal-organic frameworks (MOFs), because different pore size and shape as well as functionality can be controlled and adjusted by using pillars with different geometrical and chemical features. Our approach takes advantage of the readily accessible layered Zn-1,2,4-triazolate motif and diverse dicarboxylate ligands with variable length and functional groups, to prepare seven Zn-triazolate-dicarboxylate pillar-layered MOFs. Six different gases (N2, H2, CO2, C2H2, C2H4, and CH4) were used to systematically examine the dependency of gas sorption properties on chemical and geometrical properties of those MOFs as well as their potential applications in gas storage and separation. All of these pillar-layered MOFs show not only remarkable CO2 uptake capacity, but also high CO2 over CH4 and C2 hydrocarbons over CH4 selectivity. An interesting observation is that the BDC ligand (BDC = benzenedicarboxylate) led to a material with the CO2 uptake outperforming all other metal-triazolate-dicarboxylate MOFs, even though most of them are decorated with amino groups, generally believed to be a key factor for high CO2 uptake. Overall, the data show that the exploration of the synergistic effect resulting from combined tuning of functional groups and pore size may be a promising strategy to develop materials with the optimum integration of geometrical and chemical factors for the highest possible gas adsorption capacity and separation performance.
在新型材料的设计中，那些具有罕见且特殊组成和结构特征的材料通常备受重视且被追捧。另一方面，具有常见且更容易获得结构模式的材料往往能提供更丰富且无与伦比的组成和结构多样性，这使得它们成为系统探究组成 - 结构 - 性能关系的更合适平台。我们在此聚焦于一类这样的材料，即柱撑层状金属有机框架（MOF），因为通过使用具有不同几何和化学特征的支柱，可以控制和调节不同的孔径、形状以及功能。我们的方法利用易于获得的层状Zn - 1,2,4 - 三唑配体基序和具有可变长度及官能团的多种二羧酸配体，制备了七种Zn - 三唑 - 二羧酸柱撑层状MOF。使用六种不同的气体（N₂、H₂、CO₂、C₂H₂、C₂H₄和CH₄）来系统研究这些MOF的气体吸附性能对其化学和几何性质的依赖性以及它们在气体存储和分离中的潜在应用。所有这些柱撑层状MOF不仅表现出显著的CO₂吸附容量，而且对CH₄具有高CO₂/CH₄选择性，对CH₄具有高C₂烃/C₂H₄选择性。一个有趣的发现是，BDC配体（BDC = 苯二甲酸）导致一种材料的CO₂吸附性能优于所有其他金属 - 三唑 - 二羧酸MOF，尽管其中大多数都带有氨基，而氨基通常被认为是高CO₂吸附的关键因素。总体而言，数据表明探索官能团和孔径联合调节所产生的协同效应可能是一种有前景的策略，以开发出几何和化学因素实现最佳整合、具有尽可能高的气体吸附容量和分离性能的材料。
