Chemically Stable Guanidinium Covalent Organic Framework for the Efficient Capture of Low-Concentration Iodine at High Temperatures.

The capture of radioactive I2 vapor from nuclear waste under industrial operating conditions remains a challenging task, as the practical industrial conditions of high temperature (≥150 °C) and low I2 concentration (∼150 ppmv) are unfavorable for I2 adsorption. We report a novel guanidinium-based covalent organic framework (COF), termed TGDM, which can efficiently capture I2 under industrial operating conditions. At 150 °C and 150 ppmv I2, TGDM exhibits an I2 uptake of ∼30 wt %, which is significantly higher than that of the industrial silver-based adsorbents such as Ag@MOR (17 wt %) currently used in the nuclear fuel reprocessing industry. Characterization and theoretical calculations indicate that among the multiple types of adsorption sites in TGDM, only ionic sites can bond to I2 through strong Coulomb interactions under harsh conditions. The abundant ionic groups of TGDM account for its superior I2 capture performance compared to various benchmark adsorbents. In addition, TGDM exhibits exceptionally high chemical and thermal stabilities that fully meet the requirements of practical radioactive I2 capture (high-temperature, humid, and acidic environment) and differentiate it from other ionic COFs. Furthermore, TGDM has excellent recyclability and low cost, which are unavailable for the current industrial silver-based adsorbents. These advantages make TGDM a promising candidate for capturing I2 vapor during nuclear fuel reprocessing. This strategy of incorporating chemically stable ionic guanidine moieties in COF would stimulate the development of new adsorbents for I2 capture and related applications.

Ionic Functionalization of Multivariate Covalent Organic Frameworks to Achieve an Exceptionally High Iodine-Capture Capacity.

Adsorption-based iodine (I2 ) capture has great potential for the treatment of radioactive nuclear waste. In this study, we apply a "multivariate" synthetic strategy to construct ionic covalent organic frameworks (iCOFs) with a large surface area, high pore volume, and abundant binding sites for I2 capture. The optimized material iCOF-AB-50 exhibits a static I2 uptake capacity of 10.21 g g-1 at 75 °C and a dynamic uptake capacity of 2.79 g g-1 at ≈400 ppm I2 and 25 °C, far exceeding the performances of previously reported adsorbents under similar conditions. iCOF-AB-50 also exhibits fast adsorption kinetics, good moisture tolerance, and full reusability. The promoting effect of ionic groups on I2 adsorption has been elucidated by experimentally identifying the iodine species adsorbed at different sites and calculating their binding energies. This work demonstrates the essential role of balancing the textural properties and binding sites of the adsorbent in achieving a high I2 capture performance.

Zinc Porphyrin/Imidazolium Integrated Multivariate Zirconium Metal-Organic Frameworks for Transformation of CO2 into Cyclic Carbonates.

The design and synthesis of metal-organic frameworks (MOFs) enclosed with multiple catalytic active sites is favorable for cooperative catalysis, but is is still challenging. Herein, we developed a sequential postsynthetic ionization and metalation strategy to prepare bifunctional multivariate Zr-MOFs incorporating zinc porphyrin and imidazolium functionalities. Using this facile strategy, tetratopic [5,10,15,20-tetrakis(4-carboxyphenyl)porphyrinato]zinc(II) (ZnTCPP) ligands were successfully installed into the cationic Zr-MOF to obtain ZnTCPP⊂(Br-)Etim-UiO-66. These MTV-MOFs, including TCPP⊂Im-UiO-66, TCPP⊂(Br-)Etim-UiO-66, and ZnTCPP⊂(Br-)Etim-UiO-66, were well characterized and used in CO2 capture and conversion into cyclic carbonate from allyl glycidyl ether and CO2 under cocatalyst-free and 1 bar CO2 pressure conditions. It was found that the structural features and CO2 affinity properties of these MTV-MOFs can be tuned by introducing imidazolium groups or doping zinc sites. Additionally, ZnTCPP⊂(Br-)Etim-UiO-66 exhibited enhanced catalytic activities compared to other MTV-MOFs herein for obtaining the 3-allyloxy-1,2-proplyene carbonate product, which was attributed to the cooperative effect of Zn2+ sites and Br- ions in this microporous ionic MTV-MOF. ZnTCPP⊂(Br-)Etim-UiO-66 can be recycled easily and used at least three times.

Synthesis and fungicidal activities of novel benzothiophene-substituted oxime ether strobilurins.

Twenty-one novel benzothiophene-substituted oxime ether strobilurins, which employed a benzothiophene group to stabilise the E-styryl group in Enoxastrobin (an unsaturated oxime strobilurin fungicide developed by Shenyang Research Institute of Chemical Industry, China) were designed and synthesised. The biological assay indicated that most compounds exhibited good or excellent fungicidal activities, especially against Colletotrichum lagenarium and Puccinia sorghi Schw. In addition, methyl 3-methoxypropenoate oxime ethers and N-methoxy-carbamic acid methyl esters exhibited good in vivo fungicidal activities against Erysiphe graminis, Colletotrichum lagenarium and Puccinia sorghi Schw. under the tested concentrations. Notably, (E,E)-methyl 3-methoxy-2-(2-((((6-chloro-1-(1H-benzo[b]thien-2-yl)ethylidene)amino)oxy)methyl)phenyl)propenoate (5E) exhibited more potent in vivo fungicidal activities against nearly all of the tested fungi at a concentration of 0.39 mg/L compared to Enoxastrobin.

Efficient and simultaneous capture of iodine and methyl iodide achieved by a covalent organic framework.

Radioactive molecular iodine (I2) and organic iodides, mainly methyl iodide (CH3I), coexist in the off-gas stream of nuclear power plants at low concentrations, whereas few adsorbents can effectively adsorb low-concentration I2 and CH3I simultaneously. Here we demonstrate that the I2 adsorption can occur on various adsorptive sites and be promoted through intermolecular interactions. The CH3I adsorption capacity is positively correlated with the content of strong binding sites but is unrelated to the textural properties of the adsorbent. These insights allow us to design a covalent organic framework to simultaneously capture I2 and CH3I at low concentrations. The developed material, COF-TAPT, combines high crystallinity, a large surface area, and abundant nucleophilic groups and exhibits a record-high static CH3I adsorption capacity (1.53 g·g-1 at 25 °C). In the dynamic mixed-gas adsorption with 150 ppm of I2 and 50 ppm of CH3I, COF-TAPT presents an excellent total iodine capture capacity (1.51 g·g-1), surpassing various benchmark adsorbents. This work deepens the understanding of I2/CH3I adsorption mechanisms, providing guidance for the development of novel adsorbents for related applications.

Removal of anionic hexavalent chromium and methyl orange pollutants by using imidazolium-based mesoporous poly(ionic liquid)s as efficient adsorbents in column.

Poly(ionic liquid)s (PILs) are attractive for their various applications, but the use of porous PILs have rarely been reported in anionic pollutants removal via ion-exchange by column. Herein, we report a serial of crosslinked imidazolium-based mesoporous PILs with Cl- and Br- as anions for hexavalent chromium (Cr(VI)) and methyl orange (MO) removal. Among them, PDVIm-Cl-SCD, from the free-radical polymerization of a dicationic monomer (N,N'-methylene-bis(1-(3-vinylimidazolium)) chloride, DVIm-Cl) and further supercritical carbon dioxide drying (SCD), displayed a very high sorption capacity (328.2 mg g-1 at 25 °C) and excellent utilization of adsorption sites (UOA, 86.2%) towards Cr(VI), and an unprecedentedly high sorption capacity (1615.0 mg g-1 at 25 °C) with a UOA of 67.4% to MO. Moreover, PDVIm-Cl-SCD also exhibited a broad pH range, excellent regeneration and remarkable reusability. Regarding to Cr(VI) removal, the volume of saturated KCl aqueous used for regenerating the Cr(VI) saturated PDVIm-Cl-SCD column (7.5-9.5 mL) was much less than the volume of treated Cr(VI) solution (160-200 mL). For MO removal, the volume of saturated NaCl solution used for regenerating the MO saturated PDVIm-Cl-SCD column (10.5-13.5 mL) was also much less than the volume of treated MO solution (220-235 mL), implying the great potential of PDVIm-Cl-SCD in sustainable wastewater treatment.

Accelerating the water splitting kinetics of CoP microcubes anchored on a graphene electrocatalyst by Mn incorporation.

CoP is considered as an efficient electrocatalyst for the hydrogen evolution reaction (HER) in acidic electrolytes but its performance in alkaline solutions is generally poor because of its slow reaction kinetics, which further limits its application in overall water splitting. Herein, we demonstrate a strategy to greatly accelerate its HER and OER kinetics in alkaline solutions through Mn incorporation. Ternary Mn x Co1-x P microcubes with a tunable Mn/Co ratio strongly anchored on rGO were synthesized using Prussian blue analogues as precursors. The synergy between the high activity of Mn x Co1-x P microcubes and the good conductivity of rGO leads to the superior performance of the hybrid toward water splitting in 1 M KOH. The optimized Mn0.6Co0.4P-rGO electrocatalyst shows high activity and stability towards both the HER and OER with low overpotentials of 54 and 250 mV at 10 mA cm-2, respectively. Furthermore, the water electrolyzer using Mn0.6Co0.4P-rGO as both the cathode and anode only requires a cell voltage as low as 1.55 V to reach a current density of 10 mA cm-2, making Mn0.6Co0.4P-rGO a competitive and cost-effective electrocatalyst for water splitting.

An imidazolium-functionalized mesoporous cationic metal-organic framework for cooperative CO2 fixation into cyclic carbonate.

A mesoporous cationic Cr-MOF, termed FJI-C10, containing imidazolium moieties, Lewis acidic Cr3+ sites and free halogens is constructed for the first time by a topology-guided one-pot synthesis. FJI-C10 exhibits excellent performances in CO2 adsorption (20.2 wt% at 273 K and 1 bar) and chemical fixation of CO2 into cyclic carbonates without the use of co-catalyst under atmospheric pressure.

Design, synthesis, and biological activity of oxime ether strobilurin derivatives containing indole moiety as novel fungicide.

Twenty-one novel oxime ether strobilurins containing indole moiety, which employed an indole group to stabilize the E-styryl group in Enoxastrobin, were designed and synthesized. The biological assay indicated that most compounds exhibited potent fungicidal activities. The structure-activity relationship study demonstrated that the synthesized methyl 3-methoxypropenoate oxime ethers 7b-e exhibited remarkably high activities among all the synthesized oxime ether compounds 7. Moreover, the fungicidal activities of methyl α-(methoxyimino)benzeneacetate oxime ethers compounds 7f-i and N-methoxy-carbamic acid methyl esters compounds 7j-m showed significant differences compared to the corresponding products of ammonolysis.

Design, synthesis and structure-activity relationship of novel oxime ether strobilurin derivatives containing substituted benzofurans.

BACKGROUND: Strobilurins are one of the most important classes of agricultural fungicides. To discover new strobilurin analogues with broad spectrum and high activity, a series of novel oxime ether strobilurin derivatives containing substituted benzofurans in the side chain were synthesised and bioassayed. RESULTS: The synthesised compounds were characterised by (1) H NMR, (13) C NMR, MS and HRMS. Bioassays demonstrated that most target compounds possessed good or excellent fungicidal activities, especially against Erysiphe graminis and Pyricularia oryzae. Furthermore, methyl 3-methoxypropenoate oxime ethers exhibited remarkably higher activities against E. graminis, Colletotrichum lagenarium and Puccinia sorghi Schw. Notably, (E,E)-methyl 3-methoxy-2-{2-[({[5-fluoro-1-(benzofuran-2-yl)ethylidene]amino}oxy)methyl]phenyl}propenoate (BSF2) and (E,E)-methyl 3-methoxy-2-{2-[({[5-chloro-1-(benzofuran-2-yl)ethylidene]amino}oxy)methyl]phenyl}propenoate (BSF3) were identified as the most promising candidates for further study. CONCLUSION: The present work demonstrates that oxime ether strobilurin derivatives containing benzofurans can be used as possible lead compounds for developing novel fungicides.