Two Solvent-Induced In(III)-Based Metal-Organic Frameworks with Controllable Topology Performing High-Efficiency Separation of C2H2/CH4 and CO2/CH4

Meng Feng; Peipei Zhou; Jingyu Wang; Xirong Wang; Dongmei Wang; Chunxia Li

doi:10.1021/acs.inorgchem.2c00694

Two Solvent-Induced In(III)-Based Metal-Organic Frameworks with Controllable Topology Performing High-Efficiency Separation of C₂H₂/CH₄ and CO₂/CH₄

Inorg Chem. 2022 Jul 25;61(29):11057-11065. doi: 10.1021/acs.inorgchem.2c00694. Epub 2022 Jul 11.

Authors

Meng Feng¹, Peipei Zhou¹, Jingyu Wang¹, Xirong Wang¹, Dongmei Wang¹, Chunxia Li²

Affiliations

¹ Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004, P. R. China.
² Institute of Molecular Sciences and Engineering, Shandong University, Qingdao 266237, P. R. China.

PMID: 35816327
DOI: 10.1021/acs.inorgchem.2c00694

Abstract

For pure acetylene manufacturing and natural gas purification, the development of porous materials displaying highly selective C₂H₂/CH₄ and CO₂/CH₄ separation is greatly important but remains a major challenge. In this work, a plausible strategy involving solvent-induced effects and using the flexibility of the ligand conformation to make two In(III) metal-organic frameworks (MOFs) is developed, showing topological diversity and different stability. The X-shaped tetracarboxylic ligand H₄TPTA ([1,1':3',1″-terphenyl]-4,4',4″,6'-tetracarboxylic acid) was selected to construct two new heteroid In MOFs, namely, {[CH₃NH₃][In(TPTA)]·2(NMF)} (MOF 1) and {[In₂(TPTA)(OH)₂]·2(H₂O)·(DMF)} (MOF 2). MOF 1 is a (4, 4)-connected net showing a pts topology with a large channel that is not conducive to fine gas separation. By contrast, with the reduction of SBU from uninucleated In to an {In-OH-In}_n chain, MOF 2 has a (4, 6)-connected net with the fsc topology with an ∼5 Å suitable micropore to confine matching small gas. The permanent porosity of MOF 2 leads to the preferential adsorption of C₂H₂ over CO₂ with superior C₂H₂/CH₄ (332.3) and CO₂/CH₄ (31.2) separation selectivities. Meanwhile, the cycling dynamic breakthrough experiments showed that the high-purity C₂H₂ (>99.8%) capture capacities of MOF 2 were >1.92 mmol g^-1 from a binary C₂H₂/CH₄ mixture, and its separation factor reached 10.