A flexible two-dimensional layered metal–organic framework functionalized with (trifluoromethyl)trifluoroborate: synthesis, crystal structure, and adsorption/separation properties. Issue 12 (24th February 2020)

• Record Type: Journal Article
• Authors: Kondo, Atsushi; Kajiro, Hiroshi; Nakagawa, Tomohiro; Tanaka, Hideki; Kanoh, Hirofumi
• Is Part Of: Dalton transactions. Volume 49:Issue 12(2020)
• Page Start: 3692
• Page End: 3699
• Publication Date: 2020-02-24
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/c9dt04836g
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : A two-dimensional layered metal–organic framework functionalized with (trifluoromethyl)trifluoroborate (ELM-13) shows gate-type adsorption properties and good CO2 selectivity from a CO2 /N2 mixture at 273 K. Abstract : Flexible porous materials have great potential for adsorption/separation of small molecules. In this study, a highly CO2 -selective two-dimensional (2D) layered metal–organic framework (MOF) showing gate-type adsorption properties was synthesized and fully characterized by single-crystal X-ray diffraction (XRD), in situ powder XRD, thermogravimetric analysis, inductively coupled plasma atomic emission spectroscopy, and gas adsorption/separation analyses. The MOF named ELM-13 is a 2D layered material functionalized with (trifluoromethyl)trifluoroborate to control interlayer interactions and exhibits dynamic guest accommodation/removal properties. In a gas adsorption study, the MOF showed no adsorption at low pressure followed by abrupt uptake and sudden desorption at a pressure lower than that of adsorption, i.e., gate adsorption, in the N2, O2, Ar, NO, and CO2 isotherms at the boiling/sublimation temperature of each gas. The structure of the MOF in the CO2 adsorption was influenced by both the amount adsorbed and the adsorption process. High-pressure adsorption experiments at 273 K indicated that, out of N2, O2, Ar, and CO2, only CO2 was adsorbed on the MOF below 900 kPa. The CO2 selectivity from an equimolar CO2 /N2 mixture with a total gas pressure of 1 MPa at 273 K was experimentally evaluated and compared with the CO2 selectivities of other selected porous materials theoretically, suggesting that ELM-13 is a good candidate for CO2 separation.