Diffusion and Adsorption in Covalent Organic Frameworks (Cofs) Probed by Nuclear Magnetic Resonance Methods

Published: Jan. 1, 2024

Molecular diffusion and surface dynamics within two covalent organic frameworks (COFs) have been investigated using nuclear magnetic resonance (NMR) pulsed-field gradient (PFG) relaxation. The effect of chemical functionalities the COFs on effective self-diffusivity probe molecules pore space adsorbate/adsorbent interactions were investigated. In particular, interaction water, methanol, n-octane, 1,3,5-triisopropylbenzene (1,3,5-TIPB) COF-SIOC COF-DHTA assessed. types used in this study possessed a dual Kagome structure consisting larger hexagonal smaller triangular pores. PFG NMR results show presence distinct coefficients for small molecules, such as n-octane. This behaviour is attributed to their relatively kinetic diameters, allowing them access both pores COFs. contrast, plot 1,3,5-TIPB showed single component linear behaviour, which through only, much diameter compared other prevents functional groups affects between T1/T2 relaxation measurements reveal higher strength water COF-SIOC, hydrophilic -OH COF-DHTA. Conversely, was achieved n-octane due hydrophobic nature material. work reports new insights into transport confined COFs, can help design optimisation structures applications separation catalysis.

Language: Английский

Guanidinium-Based 3d Cationic Covalent Organic Frameworks with Different Amino Modifications for the Efficient Removal of Hexafluorobisphenol a

Published: Jan. 1, 2024

Language: Английский