Introducing a Longer versus Shorter Acylhydrazone Linker to a Metal–Organic Framework: Parallel Mechanochemical Approach, Nonisoreticular Structures, and Diverse Properties
作者:Kornel Roztocki、Monika Szufla、Maciej Hodorowicz、Irena Senkovska、Stefan Kaskel、Dariusz Matoga
DOI:10.1021/acs.cgd.9b01031
日期:2019.12.4
A 20-Å-long diacylhydrazone linker was used for the first time as a building block for the construction of a metal–organic framework (MOF). The terephthalaldehyde di-isonicotinoylhydrazone (tdih) is considerably longer than its 11-Å-long monoacylhydrazone counterpart, 4-pyridinecarboxaldehyde isonicotinoylhydrazone (pcih), used so far as a MOF linker. By utilizing the two ditopic hydrazone linkers providing linear connectivity, two nonisoreticular cadmium–organic frameworks, [Cd2(oba)2(hydrazone)2]}n (with oba = 4,4′-oxybis(benzenedicarboxylate) colinker) were obtained by solution and mechanochemical methods. In spite of the same secondary building units, the frameworks differ in dimensionality as well as exhibit various stability and adsorption behavior, which are compared and discussed. The insights into structure–property relationships are provided by single-crystal X-ray diffraction (SC-XRD), temperature-dependent powder XRD, thermogravimetric analysis, CO2 (at 195 K), N2 (at 77 K) and H2O (at 298 K) gas adsorption measurements, as well as quasi-equilibrated temperature-programmed desorption and adsorption (QE-TPDA). The work opens possibilities to synthesize new functional materials based on the longer linker.
我们首次将 20 Å 长的二酰腙连接体用作构建金属有机框架 (MOF) 的构件。对苯二甲醛二异烟酰基腙(tdih)比其 11 Å 长的单酰基腙对应物 4-吡啶甲醛异烟酰基腙(pcih)要长得多,后者迄今为止一直被用作 MOF 连接体。利用这两种提供线性连接的二硝基腙连接体,通过溶液和机械化学方法获得了两种非等轴镉有机框架 [Cd2(oba)2(hydrazone)2]}n (oba = 4,4′-氧双(苯二甲酸)连接体)。尽管二级结构单元相同,但这些框架在尺寸上存在差异,并表现出不同的稳定性和吸附行为,本文对这些差异进行了比较和讨论。单晶 X 射线衍射 (SC-XRD)、随温度变化的粉末 XRD、热重分析、CO2(195 K)、N2(77 K)和 H2O(298 K)气体吸附测量,以及准平衡温度编程解吸和吸附 (QE-TPDA),提供了对结构-性能关系的深入了解。这项研究为合成基于长连接体的新型功能材料提供了可能性。