Abstract

3-Ethyl-5-trifluoromethyl-1,2,4-triazole is synthesized by a one-pot reaction. Using this asymmetric triazole ligand bearing one trifluoromethyl and one ethyl as side groups, we construct two new porous coordination polymers, MAF-9 and MAF-2F, being isostructural with the classic hydrophobic and flexible materials, FMOF-1 and MAF-2, based on symmetric triazole ligands bearing two trifluoromethyl groups or two ethyl groups, respectively. MAF-9 and MAF-2F can adsorb large amounts of organic solvents but completely exclude water, showing superhydrophobicity with water contact angles of 152^o in between those of FMOF-1 and MAF-2. MAF-9 exhibits very large N₂-induced breathing and colossal positive and negative thermal expansions like FMOF-1, but the lower molecular weight and smaller volume of MAF-9 give 16% and 4% higher gravimetric and volumetric N₂ uptakes, respectively. In contrast, MAF-2F is quite rigid and does not show the inversed temperature-dependent N₂ adsorption and large guest-induced expansion like MAF-2. Further, despite the higher molecular weight and larger volume, MAF-2F possesses 6% and 25% higher gravimetric and volumetric CO₂ uptakes, respectively. These results can be explained by the different pore sizes and side group arrangements in the two classic framework prototypes, which demonstrate the delicate roles of ligand side groups in controlling porosity, surface characteristic and flexibility.

中文翻译：

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两种具有经典结构和增加孔隙率的超疏水多孔配位聚合物的部分氟化配体

摘要

3-乙基-5-三氟甲基-1,2,4-三唑是通过一锅反应合成的。使用这种带有一个三氟甲基和一个乙基作为侧基的不对称三唑配体，我们构建了两种新的多孔配位聚合物 MAF-9 和 MAF-2F，它们与经典的疏水性和柔性材料 FMOF-1 和 MAF-2 具有同构在分别带有两个三氟甲基或两个乙基的对称三唑配体上。MAF-9 和 MAF-2F 可以吸附大量有机溶剂但完全排除水，表现出超疏水性，水接触角为 152 ^o，介于 FMOF-1 和 MAF-2 之间。MAF-9 展示了非常大的 N ₂诱导呼吸和巨大的正负热膨胀，如 FMOF-1，但 MAF-9 的较低分子量和较小体积分别使重量和体积 N ₂吸收量分别提高了 16% 和 4% 。相比之下，MAF-2F 是相当刚性的，并且没有像 MAF-2 那样表现出逆温度依赖性 N ₂吸附和大的客体诱导膨胀。此外，尽管更高的分子量和更大的体积，MAF-2F 拥有高 6% 和 25% 的重量和体积 CO ₂吸收，分别。这些结果可以通过两个经典框架原型中不同的孔径和侧基排列来解释，这证明了配体侧基在控制孔隙率、表面特性和柔韧性方面的微妙作用。