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Covalent Organic Frameworks

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https://www.readbyqxmd.com/read/30342419/molecular-simulations-of-cofs-irmofs-and-zifs-for-adsorption-based-separation-of-carbon-tetrachloride-from-air
#1
Ezgi Gulcay, Ilknur Erucar
Covalent organic frameworks (COFs), metal organic frameworks (MOFs) and zeolitic imidazolate frameworks (ZIFs) have been widely studied in gas separation applications due to their large surface areas, high pore volumes, tunable pore sizes and chemical stabilities. In this study, separation performances of 153 COFs, 14 IRMOFs and 8 ZIFs were assessed for efficient removal of carbon tetrachloride (CCl4 ) from CCl4 /Ar, CCl4 /N2 , CCl4 /O2 mixtures at 298 K and infinite dilution. The top performing three materials in each group, namely, borazine-linked polymer (BLP-2H-AA), IRMOF-11 and ZIF-6 were identified...
October 11, 2018: Journal of Molecular Graphics & Modelling
https://www.readbyqxmd.com/read/30334322/flexible-films-of-covalent-organic-framework-with-ultralow-dielectric-constants-under-high-humidity
#2
Bo Wang, Pengpeng Shao, Jie Li, Fan Chen, Li Ma, Qingbin Li, Mengxi Zhang, Junwen Zhou, Anxiang Yin, Xiao Feng
Covalent organic framework (COF) films combine the processibility of polymers with porosity and atomic precision of crystalline porous materials are long-sought-after in electronics yet hard to realize. Here, we prepared four flexible COF films with different alkoxy side chains via interfacial polymerization. The COF films exhibit ultralow dielectric constant (κ = 1.19 ± 0.04 at 105 Hz), small dielectric loss (< 0.02, 103 ~ 106 Hz), high breakdown voltage (> 63 kV cm-1) and low leakage current (10-10 A cm-2 at 1 kV cm-1)...
October 17, 2018: Angewandte Chemie
https://www.readbyqxmd.com/read/30324943/correction-a-new-triazine-based-%C3%AF-conjugated-mesoporous-2d-covalent-organic-framework-its-in-vitro-anticancer-activities
#3
Sabuj Kanti Das, Snehasis Mishra, Krishnendu Manna, Utpal Kayal, Supratim Mahapatra, Krishna Das Saha, Sasanka Dalapati, G P Das, Amany A Mostafa, Asim Bhaumik
Correction for 'A new triazine based π-conjugated mesoporous 2D covalent organic framework: its in vitro anticancer activities' by Sabuj Kanti Das et al., Chem. Commun., 2018, 54, 11475-11478.
October 16, 2018: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/30312876/novel-nanoarchitecture-of-co-mof-on-tpn-cof-hybrid-ultralowly-sensitive-bioplatform-of-electrochemical-aptasensor-toward-ampicillin
#4
Xiaokang Liu, Mengyao Hu, Minghua Wang, Yingpan Song, Nan Zhou, Linghao He, Zhihong Zhang
Owning to the misuse of the antibiotics in animal husbandry and agriculture, it is highly urgent to determine the quantification of antibiotics in biological systems by the simple, sensitive, and fast method. In this work, a novel nanoarchitecture of Co-based metal-organic frameworks (Co-MOF) and terephthalonitrile-based covalent organic framework (TPN-COF) was synthesized (represented by Co-MOF@TPN-COF), followed by the exploitation as the bioplatform of non-label aptasensor for detecting the most frequently used β-lactam antibiotics, ampicillin (AMP)...
September 27, 2018: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/30310571/mechanistic-investigations-into-the-cyclization-and-crystallization-of-benzobisoxazole-linked-two-dimensional-covalent-organic-frameworks
#5
David A Pyles, William H Coldren, Grace M Eder, Christopher M Hadad, Psaras L McGrier
Although many diverse covalent organic frameworks (COFs) have been synthesised over the past decade, our fundamental understanding of their nucleation and growth during the crystallization process has progressed slowly for many systems. In this work, we report the first in-depth mechanistic investigation detailing the role of nucleophilic catalysts during the formation of two distinct benzobisoxazole (BBO)-linked COFs. The BBO-COFs were constructed by reacting 1,3,5-tris(4-formylphenyl)benzene (TFPB) and 1,3,5-tris(4-formylphenyl)triazine (TFPT) C 3 -symmetric monomers with a C 2 -symmetric o -aminophenol substituted precursor using different nucleophiles ( e...
August 14, 2018: Chemical Science
https://www.readbyqxmd.com/read/30299921/polyanthraquinone-triazine-a-promising-anode-material-for-high-energy-lithium-ion-battery
#6
Hongwei Kang, Huili Liu, Chunxiao Li, Li Sun, Chaofeng Zhang, Hongcai Gao, Jun Yin, Baocheng Yang, Ya You, Ke-Cheng Jiang, Huijin Long, Sen Xin
A novel covalent organic framework polymer material that bears conjugated anthraquinone and triazine units in its skeleton has been prepared via a facile one-pot condensation reaction and employed as an anode material for Li-ion batteries. The conjugated units consist of C=N groups, C=O groups and benzene groups, which enable a 17-electron redox reaction with Li per repeating unit and brings a theoretical specific capacity of 1450 mAh g-1 . The polymer also shows a large specific surface area and a hierarchically porous structure to trigger interfacial Li storage and contribute to an additional capacity...
October 9, 2018: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/30297692/designed-synthesis-of-stable-light-emitting-two-dimensional-sp-2-carbon-conjugated-covalent-organic-frameworks
#7
Enquan Jin, Juan Li, Keyu Geng, Qiuhong Jiang, Hong Xu, Qing Xu, Donglin Jiang
Covalent organic frameworks enable the topological connection of organic chromophores into π lattices, making them attractive for creating light-emitting polymers that are predesignable for both the primary- and high-order structures. However, owing to linkages, covalent organic frameworks are either unstable or poor luminescent, leaving the practical synthesis of stable light-emitting frameworks challenging. Here, we report the designed synthesis of sp2 carbon-conjugated frameworks that combine stability with light-emitting activity...
October 8, 2018: Nature Communications
https://www.readbyqxmd.com/read/30295985/constructing-universal-ionic-sieves-via-alignment-of-two-dimensional-covalent-organic-frameworks
#8
Cheng Jiang, Mi Tang, Shaolong Zhu, Jidong Zhang, Yanchao Wu, Yuan Chen, Cong Xia, Chengliang Wang, Wenping Hu
Shuttle effect of electrode materials always leads to capacity loss and poor cycle life of the batteries. Two-dimensional (2D) covalent organic frameworks (COFs) with uniform and controllable nanopores provide a promising strategy for fabricating ionic sieves to inhibit the shuttle effect. However, the insoluble nature of COFs made it difficult to fabricate compact and ordered membrane of COFs. Herein, we report a novel method for facilely anisotropic ordering of 2D COFs via depositing COFs onto graphene. The resulted double-layer membrane acting as ionic sieves impressively inhibits the shuttle effect and exhibits versatility to both organic sodium-ion batteries and Li-S batteries, leading to high cycleability...
October 8, 2018: Angewandte Chemie
https://www.readbyqxmd.com/read/30289708/crystalline-2d-covalent-organic-framework-membranes-for-high-flux-organic-solvent-nanofiltration
#9
Digambar B Shinde, Guan Sheng, Xiang Li, Mayur Ostwal, Abdul-Hamid Emwas, Kuo-Wei Huang, Zhiping Lai
Two-dimensional (2D) covalent organic framework (COF) materials have the most suitable microstructure for membrane applications in order to achieve both high flux and high selectivity. Here, we report the synthesis of a crystalline TFP-DHF 2D COF membrane constructed from two precursors of 1,3,5-triformylphloroglucinol (TFP) and 9,9-dihexylfluorene-2,7-diamine (DHF) through the Langmuir-Blodgett (LB) method, for the first time. A single COF layer is precisely four-unit-cell thick and can be transferred to different support surfaces layer-by-layer...
October 5, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/30285431/covalent-organic-framework-as-fiber-coating-for-solid-phase-microextraction-of-chlorophenols-followed-by-quantification-with-gas-chromatography-mass-spectrometry
#10
Tong Wu, Xiaohuan Zang, Mengting Wang, Qingyun Chang, Chun Wang, Qiuhua Wu, Zhi Wang
Headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry was adopted for the simultaneous determination of seven chlorophenols (CPs) from honey and canned yellow peach samples. A covalent organic framework made of 1,3,5-triformylphloroglucinol (Tp) and benzidine (BD) was used as the SPME fiber coating to preconcentrate the acetylation derivatives of the CPs. The main experimental parameters including derivatization conditions, extraction temperature and time, headspace volume, salt concentration and desorption temperature were investigated...
October 4, 2018: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/30276397/layer-by-layer-preparation-of-3d-covalent-organic-framework-silica-composites-for-chromatographic-separation-of-position-isomers
#11
Hai-Long Qian, Cheng Yang, Xiu-Ping Yan
A layer-by-layer approach was developed to prepare 3D covalent organic framework COF-300/silica composites (COF-300@SiO2) with uniform morphology as the stationary phase for high performance liquid chromatography separation of position isomers with high efficiency, selectivity and precision.
October 16, 2018: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/30275507/sulfone-containing-covalent-organic-frameworks-for-photocatalytic-hydrogen-evolution-from-water
#12
Xiaoyan Wang, Linjiang Chen, Samantha Y Chong, Marc A Little, Yongzhen Wu, Wei-Hong Zhu, Rob Clowes, Yong Yan, Martijn A Zwijnenburg, Reiner Sebastian Sprick, Andrew I Cooper
Nature uses organic molecules for light harvesting and photosynthesis, but most man-made water splitting catalysts are inorganic semiconductors. Organic photocatalysts, while attractive because of their synthetic tunability, tend to have low quantum efficiencies for water splitting. Here we present a crystalline covalent organic framework (COF) based on a benzo-bis(benzothiophene sulfone) moiety that shows a much higher activity for photochemical hydrogen evolution than its amorphous or semicrystalline counterparts...
October 1, 2018: Nature Chemistry
https://www.readbyqxmd.com/read/30272444/molecular-weaving-of-covalent-organic-frameworks-for-adaptive-guest-inclusion
#13
Yuzhong Liu, Yanhang Ma, Jingjing Yang, Christian S Diercks, Nobumichi Tamura, Fangying Jin, Omar M Yaghi
The synthesis of new isoreticular non-interpenetrated woven covalent organic frameworks (COFs) was achieved by linking aldehyde-functionalized copper(I) bisphenanthroline complexes with benzidine linkers in the presence of a bulky anion, diphenylphosphinate (PO2 Ph2 - ) to give metalated COF-506-Cu and, upon removal of copper(I), the demetalated COF-506. The structures ofthese COFs were determined by a combination of powder X-ray diffraction and electron microscopy techniques. Guest-accessibility to the pores of the two frameworks was examined by vapor and dye inclusion studies and compared to the already reported doubly-interpenetrated COF-505-Cu...
October 4, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/30272437/functionalized-covalent-triazine-frameworks-for-effective-co2-and-so2-removal
#14
Yu Fu, Zhiqiang Wang, Sizhe Li, Xunming He, Chunyue Pan, Jun Yan, Guipeng Yu
Building novel frameworks as sorbents remains highly significant targeting for key environmental issues like CO2 or SO2 emissions from coal-fired power plants. Here we report the construction and tunable pore structure as well as gas adsorption properties of hierarchically porous covalent triazine-based frameworks (CTF-CSUs) functionalized by appended formic acid/formate sodium groups. The densely integrated functionalities on the pore walls endow the as-made networks strong affinity toward guest acid gases, despite their moderate BET surface areas...
October 1, 2018: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/30256633/removal-of-genx-and-perfluorinated-alkyl-substances-from-water-by-amine-functionalized-covalent-organic-frameworks
#15
Woojung Ji, Leilei Xiao, Yuhan Ling, Casey Ching, Michio Matsumoto, Ryan P Bisbey, Damian E Helbling, William R Dichtel
Per- and polyfluorinated alkyl substances (PFAS), such as perfluorooctanoic acid (PFOA), perfluorooctanesulfonate (PFOS), and ammonium perfluoro-2-propoxypropionate (GenX), contaminate ground and surface waters throughout the world. The cost and performance limitations of current PFAS removal technologies motivate efforts to develop selective and high-affinity adsorbents. Covalent organic frameworks (COFs) are unexplored yet promising adsorbents because of their high surface area and tunable pore sizes. Here we show that imine-linked two-dimensional (2D) COFs bearing primary amines adsorb GenX rapidly at environmentally relevant concentrations...
October 2, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/30256624/anthracene-resorcinol-derived-covalent-organic-framework-as-flexible-white-light-emitter
#16
Sattwick Haldar, Debanjan Chakraborty, Bibhisan Roy, Gangadhar Banappanavar, Kushwaha Rinku, Dinesh Mullangi, Partha Hazra, Dinesh Kabra, Ramanathan Vaidhyanathan
The ordered modular structure of a covalent organic framework (COF) facilitates the selective incorporation of electronically active segments that can be tuned to function cooperatively. This designability inspires developing COF-based single-source white light emitters, required in next-generation solid-state lighting. Here, we present a new anthracene-resorcinol-based COF exhibiting white light emission. The keto-enol tautomers present in the COF give rise to dual emission, which can be tuned by the O-donor and N-donor solvents...
October 17, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/30256355/a-new-triazine-based-%C3%AF-conjugated-mesoporous-2d-covalent-organic-framework-its-in-vitro-anticancer-activities
#17
Sabuj Kanti Das, Snehasis Mishra, Krishnendu Manna, Utpal Kayal, Supratim Mahapatra, Krishna Das Saha, Sasanka Dalapati, G P Das, Amany A Mostafa, Asim Bhaumik
We report a new highly crystalline 2D π-conjugated hexagonal mesoporous covalent organic framework material, TrzCOF, through the solvothermal polycondensation of 1,3,5-tri(4-formylbiphenyl) benzene [Ph7(CHO)3, TFBPB] with 2,4,6-tris(4-aminophenyl)-1,3,5-triazine (TAPT) and it displayed excellent anticancer activity for human colorectal carcinoma HCT-116 cells.
October 9, 2018: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/30247917/exploring-local-disorder-within-cau-1-frameworks-using-hyperpolarized-129xe-nmr-spectroscopy
#18
Tobias W Kemnitzer, Carsten B L Tschense, Thomas Wittmann, Ernst A Roessler, Jürgen Senker
The sorption properties of metal-organic frameworks can be influenced by introducing covalently attached functional side chains, which makes this subclass of porous materials promising for applications as diverse as gas storage and separation, catalysis and drug delivery. The incorporation of such side groups usually comes along with disorder, as the synthesis procedures rarely allow for the selection of one specific position among a larger group of equivalent sites. For a series of isoreticular CAU-1 frameworks, chosen as model compounds, one out of four positions at every linker is modified with equal probability...
September 24, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/30247881/crystalline-dioxin-linked-covalent-organic-frameworks-from-irreversible-reactions
#19
Bing Zhang, Mufeng Wei, Haiyan Mao, Xiaokun Pei, Sultan A Alshmimri, Jeffrey A Reimer, Omar M Yaghi
Triangular 2,3,6,7,10,11-hexahydroxytriphenylene (HHTP) and linear tetrafluorophthalonitrile (TFPN) or 2,3,5,6-tetrafluoro-4-pyridinecarbonitrile (TFPC) were linked by 1,4-dioxin linkages to form crystalline 2D covalent organic frameworks, termed COF-316 and -318. Unlike the condensation reactions commonly used to crystallize the great majority of COFs, the reactions used in this report are based on nucleophilic aromatic substitution reactions (SN Ar) that are considered irreversible. Our studies show that the reactivity of TFPN and TFPC with HHTP is enhanced by the nitrile substituents leading to facile reactions of planar building units to yield the present 1,4-dioxin linked COFs...
September 26, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/30247770/stk-a-python-toolkit-for-supramolecular-assembly
#20
Lukas Turcani, Enrico Berardo, Kim E Jelfs
A tool for the automated assembly, molecular optimization and property calculation of supramolecular materials is presented. stk is a modular, extensible and open-source Python library that provides a simple Python API and integration with third party computational codes. stk currently supports the construction of linear polymers, small linear oligomers, organic cages in multiple topologies and covalent organic frameworks (COFs) in multiple framework topologies, but is designed to be easy to extend to new, unrelated, supramolecules or new topologies...
September 5, 2018: Journal of Computational Chemistry
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