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Covalent Organic Frameworks

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https://www.readbyqxmd.com/read/30119973/self-assembling-covalent-organic-framework-functionalized-poly-styrene-divinyl-benzene-glycidylmethacrylate-composite-for-the-rapid-extraction-of-non-steroidal-anti-inflammatory-drugs-in-wastewater
#1
Weixia Li, Lin Huang, Dandan Guo, Yonggang Zhao, Yan Zhu
The growing use of non-steroidal anti-inflammatory drugs (NSAIDs) has seriously affected human health and ecosystems, as a result, the World Health Organization (WHO) has regarded them as emerging contaminants. NSAID's polar nature and trace amount present in wastewater make their extraction and determination challenging in modern analytical science. Therefore, regarding the need, we herein report a rapid, sensitive and selective in-syringe solid-phase extraction (SPE) method coupled with ultrahigh performance liquid chromatography and UV detector for the determination of seven NSAIDs in environmental water samples...
August 9, 2018: Journal of Chromatography. A
https://www.readbyqxmd.com/read/30114913/stable-covalent-organic-frameworks-as-efficient-adsorbents-for-high-and-selective-removal-of-aryl-organophosphorus-flame-retardant-from-water
#2
Wei Wang, Shubo Deng, Lu Ren, Danyang Li, Wenjing Wang, Mohammadtaghi Vakili, Bin Wang, Jun Huang, Yujue Wang, Gang Yu
A critical challenge in environmental remediation is the design of adsorbents with proper pore size for the removal of organic pollutants. Three covalent organic frameworks (COFs) with different pore sizes were successfully prepared by a room temperature solution-suspension method, and used to remove the typical aryl-organophosphorus flame retardant (triphenyl phosphate (TPhP)) from aqueous solution. The prepared COFs showed strong acid resistance and thermal stability. The 1,3,5-triformylphloroglucinol (TFP) reacted with benzidine (BD) (COF2) exhibited the highest sorption capacity for TPhP, followed by the reaction of TFP and 4,4''-Diamino-p-terphenyl (DT) (COF3), and the reaction of TFP and p-phenylenediamine (PDA) (COF1)...
August 17, 2018: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/30109779/room-temperature-synthesis-of-covalent-organic-framework-cof-lzu1-nanobars-in-co2-water-solvent
#3
Fanyu Zhang, Jianling Zhang, Bingxing Zhang, Xiuniang Tan, Dan Shao, Jinbiao Shi, Dongxing Tan, Lifei Liu, Jiaqi Feng, Buxing Han, Guanying Yang, Lirong Zheng, Jing Zhang
To develop facile, rapid, low-energy and environmentally benign routes for the synthesis of covalent organic frameworks (COFs) is of great interest. Here we demonstrate for the first time the utilization of CO2-dissolved water as a solvent for the room-temperature synthesis of COF. The as-synthesized COF-LZU1 particles combine advantages of good crystallinity, nanoscale size and high surface area, which have shown to be promising support for heterogeneous catalysts. Moreover, the CO2-assisted method is versatile for the room-temperature synthesis of Cu-COF-LZU1...
August 15, 2018: ChemSusChem
https://www.readbyqxmd.com/read/30100013/facile-synthesis-of-magnetic-covalent-organic-framework-nanobeads-and-application-to-magnetic-solid-phase-extraction-of-trace-estrogens-from-human-urine
#4
Lei Chen, Mingyue Zhang, Fengfu Fu, Jingguang Li, Zian Lin
A rapid and facile approach was developed for the synthesis of core-shell structured magnetic covalent organic framework nanobeads by using the monodisperse Fe3 O4 nanoparticles (NPs) as magnetic core, and 1,3,5-triformylbenzene (Tb) and benzidine (Bd) as two building blocks (denoted as Fe3 O4 @TbBd), which were explored as an adsorbent for magnetic solid-phase extraction (MSPE) of estrogens from human urine sample. The core-shell structured Fe3 O4 @TbBd nanobeads showed some attractive features involving high specific surface area (202...
September 14, 2018: Journal of Chromatography. A
https://www.readbyqxmd.com/read/30094899/direct-solar-to-electrochemical-energy-storage-in-functionalized-covalent-organic-framework
#5
Jiangquan Lv, Yan-Xi Tan, Jiafang Xie, Rui Yang, Muxin Yu, Shanshan Sun, Ming-De Li, Daqiang Yuan, Yaobing Wang
Directly converting and storing solar to electrochemical energy are of potential higher efficiency to sustainable energy society, which is bottlenecked by lacking bifunctional materials of harvesting light and reversible electrochemical energy storage simultaneously. Herein, we synthesize a covalent organic framework integrated naphthalenediimide (NDI) and triphenylamine (TPA) units (NT-COF) firstly. The NT-COF exhibits packing two-dimensional porous nanosheets with a high specific surface area of 1276 m2/g...
August 9, 2018: Angewandte Chemie
https://www.readbyqxmd.com/read/30088505/a-novel-sensitive-fluorescent-probe-of-s-2-o-8-2-and-fe-3-based-on-covalent-post-functionalization-of-a-zirconium-iv-metal-organic-framework
#6
Shu-Yin Zhu, Bing Yan
A zirconium metallic organic framework UiO-66-NH2 has been synthesized and is further modified with imidazole-2-carboxaldehyde by a covalent post synthetic route which is based on a Schiff-base reaction. The as-prepared, functionalized MOF named UiO-66-NH2-IM is fully characterized. It retains its structural integrity during the PSM process and shows excellent luminescence and good fluorescence stability in water. It has also been further utilized as a sensitive fluorescent probe for sensing ions. The results show that UiO-66-NH2-IM can be developed into a highly selective and sensitive sensor for the detection of S2O82- (detection limit, 8...
August 8, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/30087325/dual-template-engineering-of-triple-layered-nanoarray-electrode-of-metal-chalcogenides-sandwiched-with-hydrogen-substituted-graphdiyne
#7
Sifei Zhuo, Yusuf Shi, Lingmei Liu, Renyuan Li, Le Shi, Dalaver H Anjum, Yu Han, Peng Wang
Hybrid nanostructures integrating electroactive materials with functional species, such as metal-organic frameworks, covalent organic frameworks, graphdiyne etc., are of significance for both fundamental research and energy conversion/storage applications. Here, hierarchical triple-layered nanotube arrays, which consist of hydrogen-substituted graphdiyne frameworks seamlessly sandwiched between an outer layer of nickel-cobalt co-doped molybdenum disulfide nanosheets and an inner layer of mixed cobalt sulfide and nickel sulfide (Co9 S8 /Ni3 S2 ), are directly fabricated on conductive carbon paper...
August 7, 2018: Nature Communications
https://www.readbyqxmd.com/read/30084445/dramatic-improvement-of-stability-by-in-situ-linker-cyclization-of-a-metal-organic-framework
#8
Yun-Long Hou, Mu-Qing Li, Shengxian Cheng, Yingxue Diao, Filipe Vilela, Yonghe He, Jun He, Zhengtao Xu
We employ a two-step strategy for accessing crystalline porous covalent networks of highly conjugated π-electron systems. For this, we first assembled a crystalline metal-organic framework (MOF) precursor based on Zr(iv) ions and a linear dicarboxyl linker molecule featuring backfolded, highly unsaturated alkyne backbones; massive thermocyclization of the organic linkers was then triggered to install highly conjugated, fused-aromatic bridges throughout the MOF scaffold while preserving the crystalline order...
August 7, 2018: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/30077110/immunochemical-rapid-determination-of-quinoxyfen-a-priority-hazardous-pollutant
#9
Hadyn Duncan, Antonio Abad-Somovilla, Antonio Abad-Fuentes, Consuelo Agulló, Josep V Mercader
In 2013, quinoxyfen was included in the list of priority hazard pollutants of the European Water Framework Directive due to its toxicity to aquatic organisms. However, few analytical methods for the analysis of this fungicide have been reported and no rapid immunochemical methods have been published so far. In the present study, immunoreagents for quinoxyfen analysis were generated for the first time and an enzyme-linked immunosorbent assay was developed. Two carboxylated derivatives of quinoxyfen were designed on the basis of the minimum energy conformation of the target compound...
July 30, 2018: Chemosphere
https://www.readbyqxmd.com/read/30065278/facile-transformation-of-imine-covalent-organic-frameworks-into-ultrastable-crystalline-porous-aromatic-frameworks
#10
Xinle Li, Changlin Zhang, Songliang Cai, Xiaohe Lei, Virginia Altoe, Fang Hong, Jeffrey J Urban, Jim Ciston, Emory M Chan, Yi Liu
The growing interest in two-dimensional imine-based covalent organic frameworks (COFs) is inspired by their crystalline porous structures and the potential for extensive π-electron delocalization. The intrinsic reversibility and strong polarization of imine linkages, however, leads to insufficient chemical stability and optoelectronic properties. Developing COFs with improved robustness and π-delocalization is highly desirable but remains an unsettled challenge. Here we report a facile strategy that transforms imine-linked COFs into ultrastable porous aromatic frameworks by kinetically fixing the reversible imine linkage via an aza-Diels-Alder cycloaddition reaction...
July 31, 2018: Nature Communications
https://www.readbyqxmd.com/read/30062759/highly-stable-cof-supported-co-co-oh-2-nanoparticles-heterogeneous-catalyst-for-reduction-of-nitrile-nitro-compounds-under-mild-conditions
#11
Dinesh Mullangi, Debanjan Chakraborty, Anu Pradeep, Vijay Koshti, Chathakudath P Vinod, Soumendranath Panja, Sunil Nair, Ramanathan Vaidhyanathan
Ordered nanoporosity in covalent organic framework (COF) offers excellent opportunity for property development. Loading nanoparticles (nPs) onto them is one approach to introducing tailor-made properties into a COF. Here, a COF-Co/Co(OH)2 composite containing about 16 wt% of <6 nm sized Co/Co(OH)2 nPs is prepared on a N-rich COF support that catalyzes the release of theoretical equivalence of H2 from readily available, safe, and cheap NaBH4 . Furthermore, the released H2 is utilized for the hydrogenation of nitrile and nitro compounds to amines under ambient conditions in a facile one-pot reaction...
July 30, 2018: Small
https://www.readbyqxmd.com/read/30052416/convergent-covalent-organic-framework-thin-sheets-as-flexible-supercapacitor-electrodes
#12
Abdul Khayum M, Vidyanand Vijayakumar, Suvendu Karak, Sharath Kandambeth, Mohitosh Bhadra, Karthika Suresh, Nikhil Acharambath, Sreekumar Kurungot, Rahul Banerjee
Flexible supercapacitors in modern electronic equipment require light-weight electrodes, which have a high surface area, precisely integrated redox moieties, and mechanically strong flexible free-standing nature. However, the incorporation of the aforementioned properties into a single electrode remains a great task. Herein, we could overcome these challenges by a facile and scalable synthesis of the convergent covalent organic framework (COF) free-standing flexible thin sheets through solid-state molecular baking strategy...
August 13, 2018: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/30051963/pyrolysis-free-covalent-organic-polymer-for-oxygen-reduction
#13
Zhonghua Xiang, Jianing Guo, Chunyu Lin, Zhenhai Xia
Highly efficient electrocatalysts derived from metal-organic frameworks (MOFs) and covalent organic frameworks (COFs) for oxygen reduction reaction (ORR) have been developed over the past decade owning to their tailorable pores structures and rich element selection. However, the subsequent pyrolysis is often needed for the materials due to their poor intrinsic electrical conductivity and this always leads to undesirable structure changes and even destroys the original fine structures. Here, we developed a novel facial approach to synthesize the hybrid electrocatalysts by self-assembling pristine covalent organic polymer (COP) with reduced graphene oxide (rGO)...
July 27, 2018: Angewandte Chemie
https://www.readbyqxmd.com/read/30043531/carbon-rich-nanomaterials-fascinating-hydrogen-and-oxygen-electrocatalysts
#14
REVIEW
Jian Zhang, Guangbo Chen, Klaus Müllen, Xinliang Feng
Hydrogen energy is commonly considered as a clean and sustainable alternative to the traditional fossil fuels. Toward universal utilization of hydrogen energy, developing high-efficiency, low-cost, and sustainable energy conversion technologies, especially water-splitting electrolyzers and fuel cells, is of paramount significance. In order to enhance the energy conversion efficiency of the water-splitting electrolyzers and fuel cells, earth-abundant and stable electrocatalysts are essential for accelerating the sluggish kinetics of hydrogen and oxygen reactions...
July 24, 2018: Advanced Materials
https://www.readbyqxmd.com/read/30029415/covalent-organic-framework-as-a-novel-electrochemical-platform-for-highly-sensitive-and-stable-detection-of-lead
#15
Ting Zhang, Congwei Gao, Wei Huang, Yuling Chen, Yang Wang, Jianmin Wang
A sensitive and selective TAPB-DMTP-COF (TAPB, 1,3,5-tris(4-aminophenyl)benzene; DMTP, 2,5-dimethoxyterephaldehyde; COF, covalent organic framework) modified carbon paste electrode was evaluated as a novel electrochemical sensor for the determination of lead in an aqueous medium. Lead was accumulated on the TAPB-DMTP-COF surface by the complexation with the amine groups, and detected by differential pulse anodic stripping voltammetry. Due to the distinct structure features of COF, the resulting sensor revealed a fast electron transfer rate and outstanding adsorption capacity for lead...
October 1, 2018: Talanta
https://www.readbyqxmd.com/read/30027197/uracil-grafted-imine-based-covalent-organic-framework-for-nucleobase-recognition
#16
Sergio Royuela, Eduardo García-Garrido, Miguel Martín Arroyo, María J Mancheño, María M Ramos, David González-Rodríguez, Álvaro Somoza, Félix Zamora, José L Segura
An imine-based covalent organic framework (COF) decorated in its cavities with uracil groups has shown selective recognition towards adenine in water. These results show how the confinement of the base-pair inside the COF's pores allows a remarkable selective recognition in aqueous media.
August 14, 2018: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/30022581/rational-design-of-mof-cof-hybrid-materials-for-photocatalytic-h-2-evolution-in-the-presence-of-sacrificial-electron-donors
#17
Feng-Ming Zhang, Jing-Li Sheng, Zhao-Di Yang, Xiao-Jun Sun, Hong-Liang Tang, Meng Lu, Hong Dong, Feng-Cui Shen, Jiang Liu, Ya-Qian Lan
Crystalline and porous covalent organic frameworks (COFs) and metal-organic frameworks (MOFs) materials have attracted enormous attention in the field of photocatalytic H2 evolution due to their long-range order structures, large surface areas, outstanding visible light absorbance, and tunable band gaps. In this work, we successfully integrated two-dimensional (2D) COF with stable MOF. By covalently anchoring NH2 -UiO-66 onto the surface of TpPa-1-COF, a new type of MOF/COF hybrid materials with high surface area, porous framework, and high crystallinity was synthesized...
July 18, 2018: Angewandte Chemie
https://www.readbyqxmd.com/read/30021065/covalent-organic-framework-covalent-organic-framework-bilayer-membranes-for-highly-selective-gas-separation
#18
Hongwei Fan, Alexander Mundstock, Armin Feldhoff, Alexander Knebel, Jiahui Gu, Hong Meng, Jürgen Caro
Covalent organic frameworks (COFs) have been proposed as alternative candidates for molecular sieving membranes due to their chemical stability. However, developing COF membranes with narrowed apertures close to the size of common gas molecules is a crucial task for selective gas separation. Herein, we demonstrate a new type of a two-dimensional layered-stacking COF-COF composite membrane in bilayer geometry synthesized on a porous support by successively regulating the growth of imine-based COF-LZU1 and azine-based ACOF-1 layers via a temperature-swing solvothermal approach...
July 20, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/30020769/enhancing-gas-sorption-and-separation-performance-via-bisbenzimidazole-functionalization-of-highly-porous-covalent-triazine-frameworks
#19
Jianfeng Du, Yuchuan Liu, Rajamani Krishna, Yue Yu, Yuanzheng Cui, Shun Wang, Yunling Liu, Xiaowei Song, Zhiqiang Liang
In this paper, a series of bisbenzimidazole-functionalized highly porous covalent triazine frameworks (CTF-BIBs) has been constructed from a new organic building block, 1,4-bis(5-cyano-1 H-benzimidazole-2-yl)benzene, via ionothermal polymerization. The physical porosity and gas adsorption properties of these CTF-BIBs were characterized, and the resulting CTF-BIBs exhibit significantly high Brunauer-Emmett-Teller surface areas (1636-2088 m2 g-1 ) and notable CO2 uptakes (86.4-97.6 cm3 g-1 at 273 K and 1 bar; 48...
August 8, 2018: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/30018290/water-dispersible-peg-curcumin-amine-functionalized-covalent-organic-framework-nanocomposites-as-smart-carriers-for-in-vivo-drug-delivery
#20
Guiyang Zhang, Xinle Li, Qiaobo Liao, Yanfeng Liu, Kai Xi, Wenyu Huang, Xudong Jia
Covalent organic frameworks (COFs) as drug-delivery carriers have been mostly evaluated in vitro due to the lack of COFs nanocarriers that are suitable for in vivo studies. Here we develop a series of water-dispersible polymer-COF nanocomposites through the assembly of polyethylene-glycol-modified monofunctional curcumin derivatives (PEG-CCM) and amine-functionalized COFs (APTES-COF-1) for in vitro and in vivo drug delivery. The real-time fluorescence response shows efficient tracking of the COF-based materials upon cellular uptake and anticancer drug (doxorubicin (DOX)) release...
July 17, 2018: Nature Communications
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