Two urea-functionalized pcu metal–organic frameworks based on a pillared-layer strategy for gas adsorption and separation. Issue 18 (20th August 2020)

• Record Type: Journal Article
• Authors: Qiao, Junyi; Liu, Xueshibojie; Liu, Xin; Liu, Xinyao; Zhang, Lirong; Liu, Yunling
• Is Part Of: Inorganic chemistry frontiers. Volume 7:Issue 18(2020)
• Page Start: 3500
• Page End: 3508
• Publication Date: 2020-08-20
• Subjects: Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/d0qi00641f
• Languages: English
• ISSNs: 2052-1553

Abstract

Abstract : Two pcu type Cu-MOFs based on urea-functionalized ligands have been synthesized by a pillared-layer strategy. Compound 1 shows good adsorption and separation behaviors of CO2, C2 H6, and C3 H8 over CH4, compound 2 exhibits a gate-opening behavior for N2 adsorption. Abstract : Herein, by using pillaring ligands with different lengths, two copper-based metal–organic frameworks, compounds 1 (Cu2 (bada)2 (dabco)) and 2 (Cu2 (bada)2 (bipy)) (bada = 4, 4′-carbonylbis(azanediyl)di-benzoic acid, dabco = 1, 4-diazabicyclo[2.2.2]octane, bipy = 4, 4′-bipyridine) with the urea-functionalized ligand bada, have been successfully synthesized using a pillared-layer strategy. Both 1 and 2 exhibit two-dimensional square lattice (sql ) layers pillared by dabco and bipy, respectively, and feature pcu topology. Different to dabco in 1, the pillaring ligand 4, 4′-bipyridine with longer length forms a doubly interpenetrated structure of 2 . Both compounds display good thermal stabilities and permanent porosities. 1 exhibits good performance for CO2 (32 cm 3 g −1 ), C2 H6 (58 cm 3 g −1 ), and C3 H8 (105 cm 3 g −1 ) capture among MOFs without open metal sites. In particular, 1 possesses high Q st for CO2 (32.8 kJ mol −1 ), C2 H6 (37.2 kJ mol −1 ), and C3 H8 (40.3 kJ mol −1 ) adsorption and outstanding selectivities for CO2 (5.7), C2 H6 (28), and C3 H8 (224) over CH4 at 298 K. Density functional theory (DFT)-based calculations further prove the hydrogen-bond interactions and σ–π interactions between gas molecules and urea-based ligands. 2 exhibits a gate-opening behavior for N2, Ar and CO2 . Compound 1 could be seen as a significant potential material for gas storage and separation.