Browsing by Author "Farha, Omar K."

Filter results by typing the first few letters
Now showing 1 - 2 of 2
  • Thumbnail Image
    Article
    From 2-methylimidazole to 1,2,3-triazole: a topological transformation of ZIF-8 and ZIF-67 by post-synthetic modification
    (ROYAL SOC CHEMISTRYTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND, 2017) Erkartal, Mustafa; Erkilic, Ufuk; Tam, Benjamin; Yazaydin, Ozgur; Hupp, Joseph T.; Farha, Omar K.; Sen, Unal; 0000-0002-0618-1979; 0000-0003-1849-9180; 0000-0002-9772-128X; AGÜ, Mühendislik Fakültesi, Malzeme Bilimi ve Nanoteknoloji Mühendisliği Bölümü; Erkartal, Mustafa; Erkilic, Ufuk; Usta, Hakan
    Bridging ligand replacement in zeolitic imidazolate frameworks, ZIF-8 and ZIF-67, by 1,2,3-triazole was investigated. A complete substitution of 2-methylimidazole by 1,2,3-triazole resulted in a topological transformation of the parent framework from a sodalite (SOD) network to a diamond (DIA) network.
  • Thumbnail Image
    Article
    Proton Conducting Self-Assembled Metal-Organic Framework/Polyelectrolyte Hollow Hybrid Nanostructures
    (AMER CHEMICAL SOC1155 16TH ST, NW, WASHINGTON, DC 20036, 2016) Sen, Unal; Erkartal, Mustafa; Kung, Chung-Wei; Ramani, Vijay; Hupp, Joseph T; Farha, Omar K.; 0000-0003-3736-5049; 0000-0002-9772-128X; AGÜ, Mühendislik Fakültesi, Makine Mühendisliği Bölümü; Sen, Unal; Erkartal, Mustafa
    Herein, a room temperature chemical process to synthesize functional, hollow nanostructures from zeolitic imidazolate framework-8 (ZIF-8) and poly(vinylphosphonic acid) (PVPA) is reported. Syntheses are initiated by physically blending the components a process that is accompanied first by encapsulation of ZIF-8 crystallites by PVPA and then by fragmentation of the crystallites. The fragmentation process is driven by partial displacement of the methyl-imidazolate ligands of Zn(II) in ZIF-8 by phosphonate groups on PVPA. Differences in rates of diffusion for the components of the reactive mixture yield a Kirkendall-like effect that is expressed as a hollow-particle morphology. The obtained hollow nanostructures feature hybrid shells containing PVPA, ZIF-8, and their cross-reacted products. The hybrid structures display substantial proton conductivities that increase with increasing temperature, even under the anhydrous conditions prevailing at temperatures above the boiling point of water. For example, at T = 413 K the proton conductivity of ZIF-8@PVPA reaches 3.2 (+/- 0.12) x 10(-3) S cm(-1), a value comparatively higher than that for PVPA (or ZIF-8) in isolation. The high value may reflect the availability in the hybrid structures of free (and partially free), amphoteric imidazole species, and their hydrogen-bonding interactions with phosphonate and/or phosphonic acid units. The persistence of ample conductivity at high temperature reflects the elimination of phosphonic acid group dehydration and dimerization-an effect that strikingly degrades the conductivity of pure PVPA under anhydrous conditions.