Multiple Modes of Motion: Realizing the Dynamics of CO Adsorbed in M-MOF-74 (M = Mg, Zn) by Using Solid-State NMR Spectroscopy

作者：Lucier Bryan E G; Chan Hendrick; Zhang Yue; Huang Yining^*

来源：European Journal of Inorganic Chemistry, 2016, 2016(13-14): 2017-2024.

DOI：10.1002/ejic.201501242

• Adsorption
• Carbon monoxide
• Metal-organic frameworks
• Microporous materials
• NMR spectroscopy
• Host-guest systems
• Guest dynamics
• Greenhouse gas

Metal-organic frameworks (MOFs) often exhibit high porosities and surface areas, making them ideal media for gas storage and carbon capture. MOF-74 is an intriguing porous MOF featuring one-dimensional honeycomb-shaped channels and open metal sites, and is able to adsorb poisonous CO. Variable-temperature (VT) C-13 solid-state NMR (SSNMR) experiments focusing on (CO)-C-13 adsorbed within M-MOF-74 (M = Mg, Zn) are a sensitive probe of guest motion, revealing valuable details regarding the dynamics of adsorbed CO within the MOF channels. C-13 SSNMR experiments recorded at temperatures ranging from 153 to 373 K, along with accompanying simulations, unambiguously indicate that two types of dynamic CO motion are present in MOF-74: a localized wobbling of CO on the open metal site, and a non-localized hopping of CO molecules between adjacent open metal sites. The fine details of these motions, including the motional angles and rates, are revealed and discussed. The CO dynamics in MOF-74 are then compared and contrasted with those of CO2, illustrating the similarities and differences in motion between the two types of guest molecules across the experimental temperature range.

• 出版日期2016-5