Dissem Nour, Essalhi Mohamed, Ferhi Najmeddine, Abidi Adela, Maris Thierry, Duong Adam
Département de Chimie, Biochimie et physique and Institut de Recherche sur l'Hydrogène, Université du Québec à Trois-Rivières, Trois-Rivières, Québec G9A 5H7, Canada.
Département de Chimie, Université de Montréal, Montréal, Québec H3C 3J7, Canada.
Dalton Trans. 2021 Jun 29;50(25):8727-8735. doi: 10.1039/d1dt00426c.
Layered structures of flexible mixed-linker metal-organic frameworks termed IRHs-(4 and 5) (IRH = Institut de Recherche sur l'Hydrogène) were synthesized by mixing cyclam, tetrakis(4-carboxyphenyl)benzene (TCPB), and copper and zinc metal salts respectively. The new materials characterized by single-crystal X-ray diffraction exhibited the features of HOFs and MOFs. Their structures are formed by coordination and hydrogen bonds that link metallocyclam (with Cu or Zn) and TCPB to a 2D sheet which is further packed to form a 3D structure with 1D microchannels. Remarkably, the as-synthesized IRHs-(4 and 5) contain DMF in the channels that can be exchanged with DCM and afterward removed from the framework by heating without losing their single-crystallinity. This enabled an easy elucidation of the structural transformations by single-crystal and powder X-ray diffraction analyses. Experimental studies of single-component adsorption isotherms of pure CO2, CH4, and N2 gases have been carried out for all activated IRHs. Based on the obtained adsorption isotherms, theoretical calculations using Ideal Adsorbed Solution Theory (IAST) have been performed to predict the selectivity of equimolar CO2/CH4 and CO2/N2 (1 : 1) binary mixtures. The simulations predicted outstanding selectivity for CO2/N2 than for CO2/CH4 at low pressures, reaching 185 for IRH-4 and 130 for IRH-5 at 1 bar.
通过分别混合环戊二烯、四（4-羧基苯基）苯（TCPB）以及铜和锌金属盐，合成了名为IRHs-(4和5)（IRH = 氢研究所）的柔性混合连接体金属有机框架的层状结构。通过单晶X射线衍射表征的新材料展现出了氢键有机框架（HOFs）和金属有机框架（MOFs）的特征。它们的结构由配位键和氢键形成，这些键将金属环戊二烯（含铜或锌）和TCPB连接成二维片层，该片层进一步堆积形成具有一维微通道的三维结构。值得注意的是，刚合成的IRHs-(4和5)在通道中含有N,N-二甲基甲酰胺（DMF），其可与二氯甲烷（DCM）交换，随后通过加热从框架中除去，且不会失去其单晶性。这使得通过单晶和粉末X射线衍射分析能够轻松阐明结构转变。对所有活化后的IRHs进行了纯二氧化碳、甲烷和氮气单组分吸附等温线的实验研究。基于获得的吸附等温线，利用理想吸附溶液理论（IAST）进行了理论计算，以预测等摩尔二氧化碳/甲烷和二氧化碳/氮气（1∶1）二元混合物的选择性。模拟结果预测，在低压下，二氧化碳/氮气的选择性优于二氧化碳/甲烷，在1巴时，IRH-4的选择性达到185，IRH-5的选择性达到130。
