title: Direct Structural Identification of Gas Induced Gate-Opening Coupled with Commensurate Adsorption in a Microporous Metal-Organic Framework.
abstract: Gate-opening is a unique and interesting phenomenon commonly observed in flexible porous frameworks, where the pore characteristics and/or crystal structures change in response to external stimuli such as adding or removing guest molecules. For gate-opening that is induced by gas adsorption, the pore-opening pressure often varies for different adsorbate molecules and, thus, can be applied to selectively separate a gas mixture. The detailed understanding of this phenomenon is of fundamental importance to the design of industrially applicable gas-selective sorbents, which remains under investigated due to the lack of direct structural evidence for such systems. We report a mechanistic study of gas-induced gate-opening process of a microporous metal-organic framework, [Mn(ina)2 ] (ina=isonicotinate) associated with commensurate adsorption, by a combination of several analytical techniques including single crystal X-ray diffraction, in situ powder X-ray diffraction coupled with differential scanning calorimetry (XRD-DSC), and gas adsorption-desorption methods. Our study reveals that the pronounced and reversible gate opening/closing phenomena observed in [Mn(ina)2 ] are coupled with a structural transition that involves rotation of the organic linker molecules as a result of interaction of the framework with adsorbed gas molecules including carbon dioxide and propane. The onset pressure to open the gate correlates with the extent of such interaction.
authors.affiliation: Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey, 08854, USA.|Fundamental and Computational Science Directorate, Pacific Northwest National Laboratory, Richland, Washington, 99352, USA.
authors.forename: Debasis
authors.initials: D
authors.lastname: Banerjee
authors.affiliation: Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey, 08854, USA.
authors.forename: Hao
authors.initials: H
authors.lastname: Wang
authors.affiliation: Department of Geosciences, Stony Brook University, Stony Brook, New York, 11794, USA.|Physics Department, Yeshiva University, New York, NY, 10016, USA.
authors.forename: Anna M
authors.initials: AM
authors.lastname: Plonka
authors.affiliation: Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey, 08854, USA.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Emge
authors.affiliation: Department of Geosciences, Stony Brook University, Stony Brook, New York, 11794, USA.
authors.forename: John B
authors.initials: JB
authors.lastname: Parise
authors.affiliation: Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey, 08854, USA. jingli@rutgers.edu.
authors.forename: Jing
authors.identifier: http://orcid.org/0000-0001-7792-4322
authors.initials: J
authors.lastname: Li
keywords: coordination chemistry; gas adsorption; gate-opening; hydrocarbon adsorption; metal-organic frameworks