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Yingbo Zhao†, Seung-Yul Lee‡, Nigel Becknell†, Omar M. Yaghi*†§, and C. Austen Angell*‡
† Department of Chemistry, University of California at Berkeley, and Materials Sciences Division, Lawrence Berkeley National Laboratory, Kavli Energy NanoSciences Institute at Berkeley, Berkeley, California 94720, United States
‡ School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287-1604, United States
§ King Abdulaziz City for Science and Technology, Riyadh 11442, Saudi Arabia
J. Am. Chem. Soc., Article ASAP
DOI: 10.1021/jacs.6b07078
Publication Date (Web): August 18, 2016
Copyright © 2016 American Chemical Society
*yaghi@berkeley.edu, *caa@asu.edu
While glassy materials can be made from virtually every class of liquid (metallic, molecular, covalent, and ionic), to date, formation of glasses in which structural units impart porosity on the nanoscopic level remains undeveloped. In view of the well-established porosity of metal–organic frameworks (MOFs) and the flexibility of their design, we have sought to combine their formation principles with the general versatility of glassy materials. Although the preparation of glassy MOFs can be achieved by amorphization of crystalline frameworks, transparent glassy MOFs exhibiting permanent porosity accessible to gases are yet to be reported. Here, we present a generalizable chemical strategy for making such MOF glasses by assembly from viscous solutions of metal node and organic strut and subsequent evaporation of a plasticizer–modulator solvent. This process yields glasses with 300 m2/g internal surface area (obtained from N2 adsorption isotherms) and a 2 nm pore–pore separation. On a volumetric basis, this porosity (0.33 cm3/cm3) is 3 times that of the early MOFs (0.11 cm3/cm3 for MOF-2) and within range of the most porous MOFs known (0.60 cm3/cm3 for MOF-5). We believe the porosity originates from a 3D covalent network as evidenced by the disappearance of the glass transition signature as the solvent is removed and the highly cross-linked nanostructure builds up. Our work represents an important step forward in translating the versatility and porosity of MOFs to glassy materials.
http://pubs.acs.org/doi/full/10.1021/jacs.6b07078
Dr. Nipuni-Dhanesha H. Gamage, Kyle A. McDonald and Prof. Adam J. Matzger
Version of Record online: 24 AUG 2016 | DOI: 10.1002/anie.201606926
MOFs packed with polystyrene: An unprecedented mode of reactivity of one of the best studied metal–organic frameworks, MOF-5, offers a powerful approach to polymer-hybridized porous solids. A MOF-5-polystyrene (MOF-5-PS) composite was directly produced from the monomer styrene. In the MOF-5-PS composites, polystyrene is grafted and uniformly distributed throughout, which leads to enhanced hydrolytic stability and unique guest adsorption.
An unprecedented mode of reactivity of Zn4O-based metal–organic frameworks (MOFs) offers a straightforward and powerful approach to polymer-hybridized porous solids. The concept is illustrated with the production of MOF-5-polystyrene wherein polystyrene is grafted and uniformly distributed throughout MOF-5 crystals after heating in pure styrene for 4–24 h. The surface area and polystyrene content of the material can be fine-tuned by controlling the duration of heating styrene in the presence of MOF-5. Polystyrene grafting significantly alters the physical and chemical properties of pristine MOF-5, which is evident from the unique guest adsorption properties (solvatochromic dye uptake and improved CO2capacity) as well as the dramatically improved hydrolytic stability of composite. Based on the fact that MOF-5 is the best studied member of the structure class, and has been produced at scale by industry, these findings can be directly leveraged for a range of current applications.
http://onlinelibrary.wiley.com/doi/10.1002/anie.201606926/full
Yuichi Hirai, Dr. Takayuki Nakanishi, Dr. Yuichi Kitagawa, Dr. Koji Fushimi, Dr. Tomohiro Seki, Prof. Dr. Hajime Ito and Prof. Dr. Yasuchika Hasegawa
Version of Record online: 24 AUG 2016 | DOI: 10.1002/anie.201606371Glowing zippers: Luminescent EuIIIcoordination polymers were successfully fabricated by introducing a densely packed coordination zipper structure. These hydrogen-bonded coordination polymers have a high energy transfer efficiency of 80 % and thermal stability up to 320 °C.
Novel EuIII coordination polymers [Eu(hfa)3(dpt)]n (dpt: 2,5-bis(diphenylphosphoryl)thiophene) and [Eu(hfa)3(dpedot)]n (dpedot: 2,5-bis(diphenylphosphoryl)ethylenedioxythiophene) with hydrogen-bonded zipper structures are reported. The coordination polymers are composed of EuIII ions, hexafluoroacetylacetonato ligands, and thiophene-based phosphine oxide bridges. The zig-zag orientation of single polymer chains induced the formation of densely packed coordination structures with multiple intermolecular interactions, resulting in thermal stability above 300 °C. They exhibit a high intrinsic emission quantum yield (ca. 80 %) due to their asymmetrical and low-vibrational coordination structures around EuIIIions. Furthermore, the characteristic alternative orientation of substituents also contributes to the dramatically high ligand-to-metal energy transfer efficiencies of up to 80 % in the solid state.
http://onlinelibrary.wiley.com/doi/10.1002/anie.201606371/full
Vijay S. Vyas, Medhavi Vishwakarma, Igor Moudrakovski, Frederik Haase, Gökcen Savasci, Christian Ochsenfeld, Joachim P. Spatz and Bettina V. Lotsch
Version of Record online: 22 AUG 2016 | DOI: 10.1002/adma.201603006
Covalent organic frameworks (COFs) are a new class of nanoporous polymeric vector showing promise as drug-delivery vehicles with high loading capacity and biocompatibility. The interaction between the carrier and the cargo is specifically tailored on a molecular level by H-bonding. Cell-proliferation studies indicate higher efficacy of the drug in cancer cells by nanocarrier delivery mediated by the COF.
http://onlinelibrary.wiley.com/doi/10.1002/adma.201603006/full
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