Novel Pillared-Layer-like Metal-Organic Frameworks with Quadrilateral Channels for Efficient Separation of C2H2 from C2H2/CO2 and C2H2/C2H4 Mixtures

The selective separation of C2H2 from C2H2/CO2 and C2H2/C2H4 is crucial but remains incrediblychallengingdue to their extremely similar physical characteristics and nearlyequivalent molecular kinetic diameters. Here, four novel pillared-layer-likemetal-organic frameworks (MOFs) with quadrilateral channels,SNNU-283-286, which consist of a unique two-dimensional wavelayer and carboxylic acid ligands as columns, are successfully synthesizedvia a facile solvothermal process. Interestingly, with the decreaseof the bent angle between two -COOH groups in ligands, thedistortion of the quadrilateral channel increases, and the two-dimensionalwave layer becomes more curving. The optimized SNNU-285 with appropriatestructural distortion exhibits remarkably high C2H2 adsorption capacity (124.6 cm(3) g(-1)), superior selectivity (20.2), and enhanced breakthrough intervaltimes (21.6 min g(-1) at 273 K) for C2H2/CO2 due to the exposed open metal site and thepolar furan ring. This work offers novel pillared-layer-like MOFswith quadrilateral channels for efficient C2H2 adsorption and purification. Aseries of novel pillar-layered metal-organic frameworkstuned by pillar angles with quadrilateral channels exhibit remarkablyhigh C2H2 adsorption capacity, superior selectivityvalues, and enhanced breakthrough interval times for C2H2/CO2 and C2H2/C2H4 separations.