Reversible solvent interactions with UiO-67 metal–organic frameworks

• Published in: The Journal of chemical physics 2024-01, Vol.160 (4)
• Main Authors: Goodenough, Isabella, Boyanich, Mikaela C., McDonnell, Ryan P., Castellana, Lauren, Datta Devulapalli, Venkata Swaroopa, Luo, Tian-Yi, Das, Prasenjit, Richard, Mélissandre, Rosi, Nathaniel L., Borguet, Eric
• Format: Article
• Language: English
• Subjects: Acetone; Chemical Sciences; Cross-sections; Fourier transforms; Functional groups; Heptanes; Inorganic chemistry; Isopropanol; Mass spectrometry; Metal-organic frameworks
• ISSN: 0021-9606; 1089-7690; 1089-7690
• DOI: 10.1063/5.0180924

The utility of UiO-67 Metal–Organic Frameworks (MOFs) for practical applications requires a comprehensive understanding of intermolecular host-guest MOF–analyte interactions. To investigate intermolecular interactions between UiO-67 MOFs and complex molecules, it is useful to evaluate the interactions with simple polar and non-polar analytes. This problem is approached by investigating the interactions of polar (acetone and isopropanol) and non-polar (n-heptane) molecules with functionalized UiO-67 MOFs via temperature programmed desorption mass spectrometry and temperature programmed Fourier transform infrared spectroscopy. We find that isopropanol, acetone, and n-heptane bind reversibly and non-destructively to UiO-67 MOFs, where MOF and analyte functionality influence relative binding strengths (n-heptane ≈ isopropanol > acetone). During heating, all three analytes diffuse into the internal pore environment and directly interact with the μ3-OH groups located within the tetrahedral pores, evidenced by the IR response of ν(μ3-OH). We observe nonlinear changes in the infrared cross sections of the ν(CH) modes of acetone, isopropanol, and n-heptane following diffusion into UiO-67. Similarly, acetone’s ν(C=O) infrared cross section increases dramatically when diffused into UiO-67. Ultimately, this in situ investigation provides insights into how individual molecular functional groups interact with UiO MOFs and enables a foundation where MOF interactions with complex molecular systems can be evaluated.