Switching on and off Interlayer Correlations and Porosity in 2D Covalent Organic Frameworks

Sick T, Rotter JM, Reuter S, Kandambeth S, Bach NN, Döblinger M, Merz J, Clark T, Marder TB, Bein T, Medina DD (2019)

Publication Type: Journal article

Publication year: 2019

Journal

Journal of the American Chemical Society American Chemical Society

DOI: 10.1021/jacs.9b02800

Abstract

Two-dimensional covalent organic frameworks (2D COFs) attract great interest owing to their well-defined pore structure, thermal stability, high surface area, and permanent porosity. In combination with a tunable chemical pore environment, COFs are intriguing candidates for molecular sieving based on selective host-guest interactions. Herein, we report on 2D COF structures capable of reversibly switching between a highly correlated crystalline, porous and a poorly correlated, nonporous state by exposure to external stimuli. To identify COF structures with such dynamic response, we systematically studied the structural properties of a family of two-dimensional imine COFs comprising tris(4-aminophenyl)benzene (TAPB) and a variety of dialdehyde linear building blocks including terephthalaldehyde (TA) and dialdehydes of thienothiophene (TT), benzodithiophene (BDT), dimethoxybenzodithiophene (BDT-OMe), diethoxybenzodithiophene (BDT-OEt), dipropoxybenzodithiophene (BDT-OPr), and pyrene (Pyrene-2,7). TAPB-COFs consisting of linear building blocks with enlarged π-systems or alkoxy functionalities showed significant stability toward exposure to external stimuli such as solvents or solvent vapors. In contrast, TAPB-COFs containing unsubstituted linear building blocks instantly responded to exposure to these external stimuli by a drastic reduction in COF layer correlation, long-range order, and porosity. To reverse the process we developed an activation procedure in supercritical carbon dioxide (scCO2) as a highly efficient means to revert fragile nonporous and amorphous COF polymers into highly crystalline and open porous frameworks. Strikingly, the framework structure of TAPB-COFs responds dynamically to such chemical stimuli, demonstrating that their porosity and crystallinity can be reversibly controlled by alternating steps of solvent stimuli and scCO2 activation.

Authors with CRIS profile

Timothy Clark Computer-Chemie-Centrum

Involved external institutions

Ludwig-Maximilians-Universität (LMU) DE Germany (DE) Julius-Maximilians-Universität Würzburg DE Germany (DE)

How to cite

APA:

Sick, T., Rotter, J.M., Reuter, S., Kandambeth, S., Bach, N.N., Döblinger, M.,... Medina, D.D. (2019). Switching on and off Interlayer Correlations and Porosity in 2D Covalent Organic Frameworks. Journal of the American Chemical Society. https://dx.doi.org/10.1021/jacs.9b02800

MLA:

Sick, Torben, et al. "Switching on and off Interlayer Correlations and Porosity in 2D Covalent Organic Frameworks." Journal of the American Chemical Society (2019).

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