Energy‐Efficient Iodine Uptake by a Molecular Host⋅Guest Crystal (original) (raw)
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Crystengcomm, 2013
A new three-dimensional (3D) bi-porous metal-organic framework (MOF), {[(Me 2 NH 2 ) 2 ]·[Cd 3 (5-tbip) 4 ]·2DMF} n (1) (5-tbipH 2 : 5-tert-butylisophthalic acid) has been synthesized. The 5-tbip ligand containing a hydrophobic t-butyl group and hydrophilic carboxylate groups is used to synthesize the bi-porous framework. This 3D MOF contains two types of channels, a wide mouth hydrophilic channel of dimension 7.448 × 7.676 Å 2 and a narrow mouth hydrophobic channel of dimension 2.33 × 1.926 Å 2 . Hydrophilic channels are lined with the orderly arranged dimethyl ammonium (DMA) cations which neutralize the anionic 3D framework. The guest-free form of the MOF (1′) showed interesting CO 2 selectivity over other gases such as N 2 , CH 4 , and H 2 . Since the effective pore size of the desolvated compound 1′ (∼0.6 nm: from the pore size distribution curve of CO 2 adsorption measurement) is much more than the kinetic diameter of all measured gases (CO 2 = 3.3 Å, CH 4 = 3.76 Å, N 2 = 3.64 Å and H 2 = 2.8 Å), selective capture of CO 2 by 1′ could be ascribed to the strong electrostatic interaction of CO 2 with the framework. Compound 1′ also shows reversible iodine uptake (1′ ⊂ 4I 2 : based on the sample weight measurements and TGA data) with visible color change of the compound. Interestingly, the iodine-loaded MOF showed ∼76 times increase in electrical conductivity compared to 1′. CrystEngComm, 2013, 15, 9465-9471 | 9465 This journal is CrystEngComm Paper 9466 | CrystEngComm, 2013, 15, 9465-9471 This journal is CrystEngComm, 2013, 15, 9465-9471 | 9471 This journal is
Fluorescent aminal linked porous organic polymer for reversible iodine capture and sensing
Scientific Reports, 2020
A novel triazene-anthracene-based fluorescent aminal linked porous organic polymer (TALPOP) was prepared via metal free-Schiff base polycondensation reaction of 9,10-bis-(4,6-diamino-S-triazin-2-yl)anthracene and 2-furaldehyde. The polymer has exceptional chemical and thermal stabilities and exhibit good porosity with Brunauer-Emmett-Teller surface area of 401 m 2 g −1. the combination of such porosity along with the highly conjugated heteroatom-rich framework enabled the polymer to exhibit exceptional iodine vapor uptake of up to 314 wt % and reversible iodine adsorption in solution. Because of the inclusion of the anthracene moieties, the TALPOP exhibited excellent detection sensitivity towards iodine via florescence quenching with K sv value of 2.9 × 10 3 L mol −1. the cost effective TALPOP along with its high uptake and sensing of iodine, make it an ideal material for environmental remediation. Nuclear energy is becoming one of the most feasible alternative sources to meet the ever-increasing energy demand and minimize the emission of greenhouse gases because of its high-density energy, minimal carbon footprints, and low operation cost 1-4. Despite such advantages, the potential emissions of radioactive material (such as 129 I and 131 I, 3 H, 14 CO 2 , and 85 Kr) from nuclear energy power plants is a major drawback of this technology due to the serious environmental and health effect of these materials 4,5. The long-lived radionuclides of iodine, 129 I (half-life of 1.57 × 10 7 years) and 131 I (half-life of ca. 8 days), are usually emitted in the gas form which then enters the food chain through contaminated air or by depositing into soil and water. The radioactive iodine isotopes have adverse effects on human metabolic system and health, and they were indicated as major cause of thyroid cancer 5-7. Accordingly, there is an urgent need to develop new technology and means to effectively detect, capture, and store radioactive iodine. In this context, several adsorbent materials have been studied and tested for effective sequestration and sensing of iodine 4,5,8-13. It has been reported that iodine sequestration efficiency is a function of several structural properties of the adsorbent including surface area, pore size, specific high-affinity binding sites, polar groups, and conjugated units. Thus, increasing the affinity of the host to iodine, in addition to enhanced surface area, can have tremendous effect on iodine capture 4,5,14,15. Materials like activated carbon, silica, silver-doped zeolites, chalcogenide aerogels, and microporous polymers have been reported to show good adsorption capacities for radioiodine 5,16,17. However, most of these have several shortcomings such as limited surface area, high cost, low sensitivity to iodine, and difficulty in regeneration that make them quite unsuitable for practical usage 5,18-21. For example, silver-doped zeolites are expensive and have been reported to have low adsorption capacities for iodine while metal organic frameworks, in general, are unstable in humid conditions 18-22. Porous organic polymers (POPs), on the other hand, are another class of solid porous materials that have found applications in variety of areas that include gas storage and separation, catalysis, supercapacitors, light harvesting, and iodine capture 4,7,19,23-25. POPs are getting increasing attention for iodine capture due to their high surface areas, versatility in design, tunable pore size and pore volumes, excellent thermal and chemical stability, and high physiochemical robustness. As such, the chemical structures of POPs can be tailor-made to incorporate heteroatoms with expanded conjugated systems in which the lone pairs on heteroatoms and the conjugated surfaces account for strong interactions between the polymers and iodine 12,15,26,27. For example, Liu et al. reported the preparation of novel thiophene-based porous organic networks that can capture up to 204 wt.% of
Iodine Adsorption in Tetrathiafulvalene-Based Covalent Organic Frameworks
2020
To safeguard the development of nuclear energy, practical techniques for capture and storage of radioiodine are of critical importance but remains a significant challenge. Here we report the synergistic effect of physical and chemical adsorption of iodine in tetrathiafulvalene-based covalent organic frameworks (COFs), which can markedly improve both iodine adsorption capacity and adsorption kinetics due to their strong interaction. These functionalized architectures are designed to have high specific surface areas (up to 2359 m2 g−1) for efficient physisorption of iodine, and abundant tetrathiafulvalene functional groups for strong chemisorption of iodine. We demonstrate that these frameworks achieve excellent iodine adsorption capacity (~ 8.15 g g-1) and adsorption kinetics (~ 0.69 g g-1 h-1), which are much higher than other materials reported so far, including silver-doped adsorbents, inorganic porous materials, metal−organic frameworks, porous organic frameworks, and other COFs....
Sizable iodine uptake of porous copolymer networks bearing Tröger's base units
Polymer, 2021
Copolymer networks containing Tröger's base units TBP1-3 were synthesized in very good yields from a Sonogashira cross-coupling reaction of a specially designed diethynyl Tröger's base synthon TB with various tetrabrominated aryl derivatives. Thermogravimetric analysis (TGA) of TBP1-3 discloses high 10% weight loss temperature values reaching up to 443 • C. Nitrogen adsorption measurements of the target copolymers TBP1-3 reveal a strong correlation between porosity and the geometry of the aryl spacer whose inflexible rigid structure (biphenyl, TBP1), contorted configuration (spirobifluorene, TBP2), or fused aromatic structure (pyrene, TBP3) affords Brunauer-Emmett-Teller (BET) surface areas ranging from ~586 m 2 g − 1 to ~620 m 2 g − 1. Inspection of the iodine adsorption properties of TBP1-3 reveals their significant uptake of iodine vapors reaching a maximum of 440 wt% for TBP1 whereas TBP2 exhibits a very good removal efficiency of iodine solution in hexane attaining 77% (q e = 192 mg g − 1). Furthermore, reusability tests disclose the possibility to regenerate the polymers even after several iodine adsorptions-desorption cycles.
Ferrocene-based porous organic polymers for high-affinity iodine capture
Chemical Engineering Journal, 2019
• A ferrocene-containing porous network (FcTz-POP) was synthesized by one-pot reaction. • FcTz-POP shows notably promoted iodine vapor capacity which is 1.8 times that of a reference ferrocene-free one. • We provide a simple method for strengthened binding affinity of material toward iodine.
Confinement of iodine molecules into triple-helical chains within robust metal-organic frameworks
Journal of the American Chemical Society, 2017
During the nuclear waste disposal process, radioactive iodine in fission product can be released. The widespread implementation of sustainable nuclear energy thus requires the development of efficient iodine stores that have simultaneously high capacity, stability and more importantly, storage density (and hence minimised system volume). Here, we report high I2 adsorption in a series of robust porous metal-organic materials, MFM-300(M) (M = Al, Sc, Fe, In). MFM-300(Sc) exhibits fully reversible I2 uptake of 1.54 g g-1 and its structure remains completely unperturbed upon inclusion/removal of I2. Direct observation and quantification of the adsorption, binding domains and dynamics of guest I2 molecules within these hosts have been achieved using XPS, TGA-MS, high resolution synchrotron X-ray diffraction, pair distribution function analysis, Raman, terahertz and neutron spectroscopy, coupled with density functional theory modelling. These complimentary techniques reveal a comprehensiv...