Water vapour and gas induced phase transformations in an 8-fold interpenetrated diamondoid metal–organic framework. Issue 17 (24th April 2023)

• Record Type: Journal Article
• Authors: Subanbekova, Aizhamal; Nikolayenko, Varvara I.; Bezrukov, Andrey A.; Sensharma, Debobroto; Kumar, Naveen; O'Hearn, Daniel J.; Bon, Volodymyr; Wang, Shi-Qiang; Koupepidou, Kyriaki; Darwish, Shaza; Kaskel, Stefan; Zaworotko, Michael J.
• Is Part Of: Journal of materials chemistry. Volume 11:Issue 17(2023)
• Page Start: 9691
• Page End: 9699
• Publication Date: 2023-04-24
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/d3ta01574b
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : A diamondoid coordination network undergoes reversible heat, gas or vapour induced phase transformations between small pore and large pore structures. Abstract : In this work, we report the synthesis, structural characterisation and sorption properties of an 8-fold interpenetrated diamondoid (dia) metal–organic framework (MOF) that is sustained by a new extended linker ligand, [Cd(Imibz)2 ], X-dia-2-Cd, HImibz or 2 = 4-((4-(1 H -imidazol-1-yl)phenylimino)methyl)benzoic acid. X-dia-2-Cd was found to exhibit reversible single-crystal-to-single-crystal (SC–SC) transformations between four distinct phases: an as-synthesised (from N, N -dimethylformamide) wide-pore phase, X-dia-2-Cd-α ; a narrow-pore phase, X-dia-2-Cd-β, formed upon exposure to water; a narrow-pore phase obtained by activation, X-dia-2-Cd-γ ; a medium-pore CO2 -loaded phase X-dia-2-Cd-δ . While the space group remained constant in the four phases, the cell volumes and calculated void space ranged from 4988.7 Å 3 and 47% (X-dia-2-Cd-α ), respectively, to 3200.8 Å 3 and 9.1% (X-dia-2-Cd-γ ), respectively. X-dia-2-Cd-γ also exhibited a water vapour-induced structural transformation to the water-loaded X-dia-2-Cd-β phase, resulting in an S-shaped sorption isotherm. The inflection point occurred at 18% RH with negligible hysteresis on the desorption profile. Water vapour temperature-humidity swing cycling (60% RH, 300 K to 0% RH, 333 K) indicated hydrolytic stability of X-dia-2-Cd and working capacity was retained after 128 cycles of sorbent regeneration. CO2 (at 195 K) was also observed to induce a structural transformation in X-dia-2-Cd-γ and in situ PXRD studies at 1 bar of CO2, 195 K revealed the formation of X-dia-2-Cd-δ, which exhibited 31% larger unit cell volume than X-dia-2-Cd-γ .