34374-88-4Relevant articles and documents
Large-scale synthesis of azine-linked covalent organic frameworks in water and promoted by water
Lu, Jian,Lin, Feng,Wen, Qiang,Qi, Qiao-Yan,Xu, Jia-Qiang,Zhao, Xin
, p. 6116 - 6120 (2019)
A hydrothermal procedure has been developed to produce azine-linked COFs by conducting condensation reactions of hydrazine with hydroxy-substituted 1,3,5-triformylbenzene in water. The synthesis of one representative COF was drastically promoted by water in comparison with the traditional solvothermal reactions in organic solvents. This synthesis has advantages of large-scale production, catalyst-free reaction, short reaction time, and the obtained COF exhibits higher crystallinity and surface area.
Hierarchical-Coassembly-Enabled 3D-Printing of Homogeneous and Heterogeneous Covalent Organic Frameworks
Zhang, Mingshi,Li, Longyu,Lin, Qianming,Tang, Miao,Ke, Chenfeng,Wu, Yuyang
, p. 5154 - 5158 (2019)
Covalent organic frameworks (COFs) are crystalline polymers with permanent porosity. They are usually synthesized as micrometer-sized powders or two-dimensional thin films and membranes for applications in molecular storage, separation, and catalysis. In this work, we report a general method to integrate COFs with imine or β-ketoenamine linkages into three-dimensional (3D)-printing materials. A 3D-printing template, Pluronic F127, was introduced to coassemble with imine polymers in an aqueous environment. By limitation of the degree of imine polycondensation during COF formation, the amorphous imine polymer and F127 form coassembled 3D-printable hydrogels with suitable shear thinning and rapid self-healing properties. After the removal of F127 followed by an amorphous-to-crystalline transformation, three β-ketoenamine- and imine-based COFs were fabricated into 3D monoliths possessing high crystallinity, hierarchical pores with high surface areas, good structural integrity, and robust mechanical stability. Moreover, when multiple COF precursor inks were employed for 3D printing, heterogeneous dual-component COF monoliths were fabricated with high spatial precision. This method not only enables the development of COFs with sophisticated 3D macrostructure but also facilitates the heterogeneous integration of COFs into devices with interconnected interfaces at the molecular level.
A nanoporous covalent organic framework for the green-reduction of CO2under visible light in water
Das, Anjan,Hazra Chowdhury, Arpita,Hazra Chowdhury, Ipsita,Islam, Sk. Manirul,Khan, Aslam
, p. 11720 - 11726 (2020)
Herein, we designed a sheet-like nanoporous covalent organic framework (TFP-DM COF) based nanomaterial, which was formed via an easy solvothermal synthetic method. The as-synthesized material was characterized via FTIR spectroscopy, PXRD, UV-Vis, N2 adsorption-desorption studies, TEM and FESEM techniques. We demonstrated the photocatalytic reduction of CO2 into HCOOH and HCHO using the as-synthesized COF as the active photocatalyst and water as a green solvent as well as sacrificial electron source under atmospheric pressure. It was observed that the formaldehyde production rate was 36-fold higher than the formic acid production rate under white LED light irradiation. The catalyst showed good yields for both the products, HCOOH (0.019 mole) and HCHO (0.47 mole), even under sunlight irradiation. In addition, the COF material exhibited sufficient reusability without noticeable catalyst deactivation, which suggested the material to be a promising heterogeneous photocatalyst for commercial use in the CO2 reduction reaction under green reaction conditions.
β-ketoenamine-linked covalent organic frameworks capable of pseudocapacitive energy storage
Deblase, Catherine R.,Silberstein, Katharine E.,Truong, Thanh-Tam,Abruna, Hector D.,Dichtel, William R.
, p. 16821 - 16824 (2013)
Two-dimensional covalent organic frameworks (2D COFs) are candidate materials for charge storage devices because of their micro- or mesoporosity, high surface area, and ability to predictably organize redox-active groups. The limited chemical and oxidative stability of established COF linkages, such as boroxines and boronate esters, precludes these applications, and no 2D COF has demonstrated reversible redox behavior. Here we describe a β-ketoenamine- linked 2D COF that exhibits reversible electrochemical processes of its anthraquinone subunits, excellent chemical stability to a strongly acidic electrolyte, and one of the highest surface areas of the imine- or enamine-linked 2D COFs. Electrodes modified with the redox-active COF show higher capacitance than those modified with a similar non-redox-active COF, even after 5000 charge-discharge cycles. These findings demonstrate the promise of using 2D COFs for capacitive storage.
Gelation Landscape Engineering Using a Multi-Reaction Supramolecular Hydrogelator System
Foster, Jamie S.,Zurek, Justyna M.,Almeida, Nuno M. S.,Hendriksen, Wouter E.,Le Sage, Vincent A. A.,Lakshminarayanan, Vasudevan,Thompson, Amber L.,Banerjee, Rahul,Eelkema, Rienk,Mulvana, Helen,Paterson, Martin J.,Van Esch, Jan H.,Lloyd, Gareth O.
, p. 14236 - 14239 (2015)
Simultaneous control of the kinetics and thermodynamics of two different types of covalent chemistry allows pathway selectivity in the formation of hydrogelating molecules from a complex reaction network. This can lead to a range of hydrogel materials with vastly different properties, starting from a set of simple starting compounds and reaction conditions. Chemical reaction between a trialdehyde and the tuberculosis drug isoniazid can form one, two, or three hydrazone connectivity products, meaning kinetic gelation pathways can be addressed. Simultaneously, thermodynamics control the formation of either a keto or an enol tautomer of the products, again resulting in vastly different materials. Overall, this shows that careful navigation of a reaction landscape using both kinetic and thermodynamic selectivity can be used to control material selection from a complex reaction network.
Stabilization of a Strained Heteroradialene by Peripheral Electron Delocalization
Mehr, S. Hessam M.,Patrick, Brian O.,MacLachlan, Mark J.
, p. 1840 - 1843 (2016)
Dimethylamine and 2,4,6-triformylphloroglucinol react to form a product with a highly contorted nonplanar geometry due to favorable electron delocalization. This new heteroradialene compound has been studied by X-ray diffraction, variable-temperature multinuclear NMR spectroscopy, IR spectroscopy, UV-vis spectroscopy, and ab initio calculations. Electron delocalization throughout the periphery of the central ring leads to a structure that retains very little of the aromatic characteristics of the starting material.
Self-Exfoliated Guanidinium-Based Ionic Covalent Organic Nanosheets (iCONs)
Mitra, Shouvik,Kandambeth, Sharath,Biswal, Bishnu P.,Abdul Khayum,Choudhury, Chandan K.,Mehta, Mihir,Kaur, Gagandeep,Banerjee, Subhrashis,Prabhune, Asmita,Verma, Sandeep,Roy, Sudip,Kharul, Ulhas K.,Banerjee, Rahul
, p. 2823 - 2828 (2016)
Covalent organic nanosheets (CONs) have emerged as functional two-dimensional materials for versatile applications. Although π-π stacking between layers, hydrolytic instability, possible restacking prevents their exfoliation on to few thin layered CONs from crystalline porous polymers. We anticipated rational designing of a structure by intrinsic ionic linker could be the solution to produce self-exfoliated CONs without external stimuli. In an attempt to address this issue, we have synthesized three self-exfoliated guanidinium halide based ionic covalent organic nanosheets (iCONs) with antimicrobial property. Self-exfoliation phenomenon has been supported by molecular dynamics (MD) simulation as well. Intrinsic ionic guanidinium unit plays the pivotal role for both self-exfoliation and antibacterial property against both Gram-positive and Gram-negative bacteria. Using such iCONs, we have devised a mixed matrix membrane which could be useful for antimicrobial coatings with plausible medical benefits.
Porous Organic Polymers Containing a Sulfur Skeleton for Visible Light Degradation of Organic Dyes
Cao, Yuping,Liu, Wei,Qian, Jing,Cao, Ting,Wang, Jiemin,Qin, Wenwu
, p. 2883 - 2888 (2019)
Three novel chemically stable porous organic polymers (POPs) were synthesized by the hydrothermal method; the POPs contain sulfone bonds (TpSD), no sulfur atoms (TpMD), or thioether bonds (TpTD). The catalytic mechanism of the POP with sulfone bonds was studied, and it was found that the wide visible light absorption range, high specific surface area, and the hydrophilicity of the material significantly promoted the catalytic efficiency of TpSD. The presence of O=S=O gives TpSD a higher degree of conjugation than TpMD and TpTD, so TpSD shows the strongest UV/Visible absorption and faster transmission of electrons. The photocatalytic degradation of Rhodamine B (RhB) molecules is approximately 100 % with TpSD and its pseudo-first-order rate constant is 0.0770 min?1, which is the highest among all reported non-metallic photocatalysts. Moreover, it is also the first time that sulfur-containing polymer have been used in photocatalytic degradation of dyes.
The microwave-assisted solvothermal synthesis of a novel β-ketoenamine-linked conjugated microporous polymer for supercapacitors
Chai, Shuangzhi,Hu, Nantao,Han, Yang,Zhang, Xue,Yang, Zhi,Wei, Liangming,Wang, Lin,Wei, Hao
, p. 49425 - 49428 (2016)
A novel β-ketoenamine-linked conjugated microporous polymer (KECMP-1) was facilely synthesized with a high-throughput via Schiff base microwave-assisted condensation between 1,3,5-triformylphloroglucinol and m-phenylenediamine without a template or a metal catalyst. The resultant KECMP-1 shows an outstanding capacitance retaining ability (50% of the original 252 F g-1 at 1 A g-1) with the current density as high as 200 A g-1, excellent cycling stability and long cycle life for energy storage.
General Strategy to Fabricate Metal-Incorporated Pyrolysis-Free Covalent Organic Framework for Efficient Oxygen Evolution Reaction
Gao, Zhi,Gong, Le Le,He, Xiang Qing,Luo, Feng,Su, Xue Min,Xiao, Long Hui
, (2020)
Because of the permission of the manipulations of modular construction on the atomic level, covalent organic frameworks (COFs) have attracted extensive attention in the electrocatalytic field. Owing to the lack of metal sites in pristine COFs constructed only by metal-free organic building units, it generally exhibits extremely low electrocatalytic activity. Thereby, linking metal sites on the backbone of pyrolysis-free COFs but not loading them on the surface to enhance the electrocatalytic activity is highly desirable but still remains a huge challenge. To this end, herein, we report an efficient and general cation-exchange strategy to synthesize Ni/Fe metal-ion-incorporated COFs (NixFe1-x?COF-SO3) for the oxygen evolution reaction (OER) based on the fundamental structure design of COFs. Impressively, the turnover frequency (TOF) value in Ni0.5Fe0.5?COF-SO3 reaches 0.14 s-1 at the overpotential of 300 mV, which outperforms most recently reported OER electrocatalysts, indicative of ultrahigh metal-atom utilization efficiency.
A Hexagonal Covalent Porphyrin Framework as an Efficient Support for Gold Nanoparticles toward Catalytic Reduction of 4-Nitrophenol
Ding, Zheng-Dong,Wang, Yu-Xia,Xi, Sai-Fei,Li, Yunxing,Li, Zaijun,Ren, Xuehong,Gu, Zhi-Guo
, p. 17029 - 17036 (2016)
A hexagonal porphyrin-based porous organic polymer, namely, CPF-1, was constructed by 3+2 ketoenamine condensation of the C2-symmetric porphyrin diamine 5,15-bis(4-aminophenyl)-10,20-diphenylporphyrin and 1,3,5-triformylphloroglucinol. This material exhibits permanent porosity and excellent thermal and chemical stability. CPF-1 can be employed as a superior supporting substrate to immobilize Au nanoparticles (NPs) as a result of the strong interactions between Au NPs and the CPF support. An Au@CPF-1 hybrid was synthesized by an interfacial solution infiltration method with NaBH4as reducing agent. Au NPs (5 nm) grew on CPF-1 and were distributed without aggregation. Moreover, Au@CPF-1 exhibits superior catalytic activity compared to many other reported Au-based catalysts for the reduction of 4-nitrophenol in the presence of NaBH4. In addition, Au@CPF-1 has excellent stability and recyclability, and it can be reused for three successive reaction cycles without loss of activity. The dense distribution of phenyl rings on the channel walls of the CPF support can reasonably be regarded as the active sites that adsorb the 4-nitrophenol molecule through hydrogen-bonding and C?H???π interactions, as was confirmed by the X-ray structure of model compound DAPP-Benz.
U(VI) adsorption onto covalent organic frameworks-TpPa-1
Li, Zhuo Dai,Zhang, Huai Qiang,Xiong, Xiao Hong,Luo, Feng
, p. 484 - 492 (2019)
Covalent organic frameworks (COFs) represent an exciting new type of porous organic materials, which are constructed with organic building units via strong covalent bonds. Here in, the COF-2,4,6-Triformylphloroglucinol p-Phenylenediamine (COF-TpPa-1) was
Regulating the Solvation Sheath of Li Ions by Using Hydrogen Bonds for Highly Stable Lithium–Metal Anodes
Jiang, Cheng,Jia, Qingqing,Tang, Mi,Fan, Kun,Chen, Yuan,Sun, Mingxuan,Xu, Shuaifei,Wu, Yanchao,Zhang, Chenyang,Ma, Jing,Wang, Chengliang,Hu, Wenping
, p. 10871 - 10879 (2021)
The performance of Li anodes is extremely affected by the solvation of Li ions, leading to preferential reduction of the solvation sheath and subsequent formation of fragile solid–electrolyte interphase (SEI), Li dendrites, and low coulombic efficiency (CE). Herein, we propose a novel strategy to regulate the solvation sheath, through the introduction of intermolecular hydrogen bonds with both the anions of Li salt and the solvent by small amount additives. The addition of such hydrogen bonds reduced the LUMO energy level of anions in electrolyte, promoted the formation of a robust SEI, reduced the amount of free solvent molecules, and enhanced stability of electrolytes. Based on this strategy, flat and dense lithium deposition was obtained. Even under lean electrolytes, at a current density of 1 mA cm?2 with a fixed capacity of 3 mAh cm?2, the Li–Cu cells showed an impressive CE value of 99.2 %. The Li-LiFePO4 full cells showed long-term cycling stability for more than 1000 cycles at 1 C, with a total capacity loss of only 15 mAh g?1.
Robust covalent organic frameworks with tailor-made chelating sites for synergistic capture of U(vi) ions from highly acidic radioactive waste
Yu, Jipan,Lan, Jianhui,Wang, Shuai,Zhang, Pengcheng,Liu, Kang,Yuan, Liyong,Chai, Zhifang,Shi, Weiqun
supporting information, p. 3792 - 3796 (2021/03/29)
A synergistic strategy for enhancing U(vi) capture under highly acidic conditions (2 M HNO3) by radiation resistant phosphonate-functionalized two-dimensional covalent organic frameworks with tailor-made binding sites bearing a strong affinity was described. The combination of the radiation resistant characteristic with a strong acid-resistant property endows COFs with practical capabilities for actinide capture from real radioactive liquid waste.
Covalent Organic Frameworks Enabling Site Isolation of Viologen-Derived Electron-Transfer Mediators for Stable Photocatalytic Hydrogen Evolution
Mi, Zhen,Zhou, Ting,Weng, Weijun,Unruangsri, Junjuda,Hu, Ke,Yang, Wuli,Wang, Changchun,Zhang, Kai A. I.,Guo, Jia
supporting information, p. 9642 - 9649 (2021/03/16)
Electron transfer is the rate-limiting step in photocatalytic water splitting. Viologen and its derivatives are able to act as electron-transfer mediators (ETMs) to facilitate the rapid electron transfer from photosensitizers to active sites. Nevertheless, the electron-transfer ability often suffers from the formation of a stable dipole structure through the coupling between cationic-radical-containing viologen-derived ETMs, by which the electron-transfer process becomes restricted. Herein, cyclic diquats, a kind of viologen-derived ETM, are integrated into a 2,2′-bipyridine-based covalent organic framework (COF) through a post-quaternization reaction. The content and distribution of embedded diquat-ETMs are elaborately controlled, leading to the favorable site-isolated arrangement. The resulting materials integrate the photosensitizing units and ETMs into one system, exhibiting the enhanced hydrogen evolution rate (34600 μmol h?1 g?1) and sustained performances when compared to a single-module COF and a COF/ETM mixture. The integration strategy applied in a 2D COF platform promotes the consecutive electron transfer in photochemical processes through the multi-component cooperation.
