A partially fluorinated ligand for two super-hydrophobic porous coordination polymers with classic structures and increased porosities

• 作者: Chao Wang Dong-Dong Zhou You-Wei Gan Xue-Wen Zhang Zi-Ming Ye Jie-Peng Zhang
• 来源期刊: 国家科学评论（英文版）
• 年，卷（期）: 2021,（3）
• 所属期刊栏目: RESEARCH ARTICLES
• 页码范围: 94-102
• 页数: 9页
• 语种: 英文
• DOI: 10.1093/nsr/nwaa094

摘要

3-Ethyl-5-trifluoromethyl-l,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° 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.