Tailoring adsorption induced switchability of a pillared layer MOF by crystal size engineering

Abylgazina L, Senkovska I, Ehrling S, Bon V, Petkov PS, Evans JD, Krylova S, Krylov A, Kaskel S (2021)


Publication Type: Journal article

Publication year: 2021

Journal

Book Volume: 23

Pages Range: 538-549

Journal Issue: 3

DOI: 10.1039/d0ce01497d

Abstract

The pillared layer framework DUT-8(Zn) (Zn2(2,6-ndc)2(dabco), 2,6-ndc = 2,6-naphthalenedicarboxylate, dabco = 1,4-diazabicyclo-[2.2.2]-octane, DUT = Dresden University of Technology) is a prototypical switchable MOF, showing characteristic adsorption and desorption induced open phase (op) to closed phase (cp) transformation associated with huge changes in cell volume. We demonstrate switchability strongly depends on a framework-specific critical particle size (dcrit). Superposed, the solvent removal process (pore desolvation stress contracting the framework) significantly controls the cp/op ratio after desolvation and, subsequently, the adsorption induced switchability characteristics of the system. After desolvation, the dense cp phase of DUT-8(Zn) shows no adsorption-induced reopening and therefore is non-porous for N2 at 77 K and CO2 at 195 K. However, polar molecules with a higher adsorption enthalpy, such as chloromethane at 249 K and dichloromethane (DCM) at 298 K can reopen the macro-sized crystals upon adsorption. For macro-sized particles, the outer surface energy is negligible and only the type of metal (Zn, Co, Ni) controls the DCM-induced gate opening pressure. The node hinge stiffness increases from Zn to Ni as confirmed by DFT calculations, X-ray crystal structural analysis, and low frequency Raman spectroscopy. This softer Zn-based node hinges and overall increased stabilization of cp vs. op phase shift the critical particle size at which switchability starts to become suppressed to even lower values (dcrit < 200 nm) as compared to the Ni-based system (dcrit ≈ 500 nm). Hence, the three factors affecting switchability (energetics of the empty host, (Eop-Ecp) (I), particle size (II), and desolvation stress (III)) appear to be of the same order of magnitude and should be considered collectively, not individually.

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APA:

Abylgazina, L., Senkovska, I., Ehrling, S., Bon, V., Petkov, P.S., Evans, J.D.,... Kaskel, S. (2021). Tailoring adsorption induced switchability of a pillared layer MOF by crystal size engineering. CrystEngComm, 23(3), 538-549. https://doi.org/10.1039/d0ce01497d

MLA:

Abylgazina, Leila, et al. "Tailoring adsorption induced switchability of a pillared layer MOF by crystal size engineering." CrystEngComm 23.3 (2021): 538-549.

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