title: Ultraporous, Water Stable, and Breathing Zirconium-Based Metal-Organic Frameworks with ftw Topology.
abstract: "Breathing" metal-organic frameworks (MOFs) are an emerging class of soft porous crystals (SPCs) with potential for high working capacity for gas storage applications. However, most breathing MOFs have low stability and/or low surface area. Here we report a water-stable, high surface area, breathing MOF of ftw topology, NU-1105. While Zr6-oxo clusters as nodes introduce water stability in NU-1105, its high surface area and breathing character stem from its pyrene-based tetracarboxylate (Py-FP) linkers, in which the fluorene units (F) in the FP "arms" play a key role in promoting breathing behavior. During gas sorption studies, the "closed pore" (cp) ↔ "open pore" (op) transition of NU-1105 occurs at a propane pressure of ∼3 bar. At 1 bar, NU-1105 is in its cp form and adsorbs less propane than it would in its op form, highlighting improved working capacity. In situ powder X-ray diffraction during propane sorption was used to track the cp ↔ op transition, and molecular modeling was used to elucidate the structure of the op and cp forms of NU-1105. According to TD-DFT calculations, the proposed conformations of the Py-FP linkers in the op and cp forms are consistent with the measured excitation and emission spectra of the op and cp forms of NU-1105. Similar structural transitions are also observed in the porphyrinic MOF NU-1104 depending on the identity of the porphyrin core; we observed breathing behavior if the constituent Por-PTP linker is nonmetalated.
authors.affiliation: Departments of Chemistry and Chemical and Biological Engineering, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: Pravas
authors.initials: P
authors.lastname: Deria
authors.affiliation: Departments of Chemistry and Chemical and Biological Engineering, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: Diego A
authors.initials: DA
authors.lastname: Gómez-Gualdrón
authors.affiliation: Departments of Chemistry and Chemical and Biological Engineering, Northwestern University , Evanston, Illinois 60208, United States.|Department of Chemistry, Warsaw University of Technology , Noakowskiego 3, 00-664 Warsaw, Poland.
authors.forename: Wojciech
authors.initials: W
authors.lastname: Bury
authors.affiliation: Pacific Northwest National Laboratory , Richland, Washington 99352, United States.
authors.forename: Herbert T
authors.initials: HT
authors.lastname: Schaef
authors.affiliation: Departments of Chemistry and Chemical and Biological Engineering, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: Timothy C
authors.initials: TC
authors.lastname: Wang
authors.affiliation: Pacific Northwest National Laboratory , Richland, Washington 99352, United States.
authors.forename: Praveen K
authors.initials: PK
authors.lastname: Thallapally
authors.affiliation: Departments of Chemistry and Chemical and Biological Engineering, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: Amy A
authors.initials: AA
authors.lastname: Sarjeant
authors.affiliation: Departments of Chemistry and Chemical and Biological Engineering, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: Randall Q
authors.initials: RQ
authors.lastname: Snurr
authors.affiliation: Departments of Chemistry and Chemical and Biological Engineering, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: Joseph T
authors.initials: JT
authors.lastname: Hupp
authors.affiliation: Departments of Chemistry and Chemical and Biological Engineering, Northwestern University , Evanston, Illinois 60208, United States.|Department of Chemistry, Faculty of Science, King Abdulaziz University , Jeddah 22254, Saudi Arabia.
authors.forename: Omar K
authors.initials: OK
authors.lastname: Farha