34374-88-4Relevant academic research and scientific papers
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.
Cation-Dependent Stabilization of Electrogenerated Naphthalene Diimide Dianions in Porous Polymer Thin Films and Their Application to Electrical Energy Storage
Deblase, Catherine R.,Hernández-Burgos, Kenneth,Rotter, Julian M.,Fortman, David J.,Dos S. Abreu, Dieric,Timm, Ronaldo A.,Diógenes, Izaura C. N.,Kubota, Lauro T.,Abru?a, Héctor D.,Dichtel, William R.
, p. 13225 - 13229 (2015)
Porous polymer networks (PPNs) are attractive materials for capacitive energy storage because they offer high surface areas for increased double-layer capacitance, open structures for rapid ion transport, and redox-active moieties that enable faradaic (pseudocapacitive) energy storage. Here we demonstrate a new attractive feature of PPNs - the ability of their reduced forms (radical anions and dianions) to interact with small radii cations through synergistic interactions arising from densely packed redox-active groups, only when prepared as thin films. When naphthalene diimides (NDIs) are incorporated into PPN films, the carbonyl groups of adjacent, electrochemically generated, NDI radical anions and dianions bind strongly to K+, Li+, and Mg2+, shifting the formal potentials of NDI's second reduction by 120 and 460 mV for K+ and Li+-based electrolytes, respectively. In the case of Mg2+, NDI's two redox waves coalesce into a single two-electron process with shifts of 240 and 710 mV, for the first and second reductions, respectively, increasing the energy density by over 20 % without changing the polymer backbone. In contrast, the formal reduction potentials of NDI derivatives in solution are identical for each electrolyte, and this effect has not been reported for NDI previously. This study illustrates the profound influence of the solid-state structure of a polymer on its electrochemical response, which does not simply reflect the solution-phase redox behavior of its monomers.
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.
Combined effect of nitrogen and oxygen heteroatoms and micropores of porous carbon frameworks from Schiff-base networks on their high supercapacitance
Zhou, Man,Li, Xiaoyan,Zhao, Hong,Wang, Jun,Zhao, Yaping,Ge, Fengyan,Cai, Zaisheng
, p. 1621 - 1629 (2018)
Nitrogen and oxygen heteroatom doped porous carbon frameworks (HPCFs) have been constructed through the structural evolution of 2D microporous Schiff-base frameworks from the rigid polyquinoneimine and trigonal-symmetrical triformylphloroglucinol. Owing to its predictable and controllable nitrogen and oxygen doping and pore structures, the derived HPCF material exhibits good electrochemical properties as a supercapacitor electrode with remarkable specific capacitance (479.5 F g-1 at 0.1 A g-1 and 125 F g-1 at 10 A g-1) and excellent long-term cycling stability over 10000 cycles. The combined effect of heteroatom doping and micropores on its electrochemical performance as a supercapacitor electrode is thoroughly investigated. According to the analysis of the electrochemical behavior, pores larger than 5 ? in HPCFs are effective for electrical double-layer capacitance, which is associated with the size of hydrated ions. With regard to the heteroatoms, while the quaternary nitrogen functionalities can improve electron transfer, pyrrolic and pyridinic nitrogens as well as quinone oxygen are the most conducive functional groups for pseudocapacitive performance.
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.
Targeted Drug Delivery in Covalent Organic Nanosheets (CONs) via Sequential Postsynthetic Modification
Mitra, Shouvik,Sasmal, Himadri Sekhar,Kundu, Tanay,Kandambeth, Sharath,Illath, Kavya,Díaz Díaz, David,Banerjee, Rahul
, p. 4513 - 4520 (2017)
Covalent organic nanosheets (CONs) have emerged as a new class of functional two-dimensional (2D) porous organic polymeric materials with a high accessible surface, diverse functionality, and chemical stability. They could become versatile candidates for targeted drug delivery. Despite their many advantages, there are limitations to their use for target specific drug delivery. We anticipated that these drawbacks could be overturned by judicious postsynthetic modification steps to use CONs for targeted drug delivery. The postsynthetic modification would not only produce the desired functionality, it would also help to exfoliate to CONs as well. In order to meet this requirement, we have developed a facile, salt-mediated synthesis of covalent organic frameworks (COFs) in the presence of p-toluenesulfonic acid (PTSA). The COFs were subjected to sequential postsynthetic modifications to yield functionalized targeted CONs for targeted delivery of 5-fluorouracil to breast cancer cells. This postsynthetic modification resulted in simultaneous chemical delamination and functionalization to targeted CONs. Targeted CONs showed sustained release of the drug to the cancer cells through receptor-mediated endocytosis, which led to cancer cell death via apoptosis. Considering the easy and facile COF synthesis, functionality based postsynthetic modifications, and chemical delamination to CONs for potential advantageous targeted drug delivery, this process can have a significant impact in biomedical applications.
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.
Insight into volatile iodine uptake properties of covalent organic frameworks with different conjugated structures
Yang, Yuling,Xiong, Xiaohong,Fan, Yaling,Lai, Zhenqin,Xu, Zhenzhen,Luo, Feng
, (2019)
The effective capture and storage of volatile radionuclide iodine from the nuclear waste stream is of great significance for environment remediation. Here we synthetize two types of two-dimensional (2D) covalent organic frameworks (COFs) for iodine vapor uptake, including COF-LZU1 with a whole π-π conjugated structure and TpPa-1 with a combination of π-π and p-π conjugated structure. The capacities for iodine vapor uptake are acquired for COF-LZU1 (530 wt%) and TpPa-1 (245 wt%). Thorough studies reveal that the large and intact π-π conjugated system formed by phenyl rings and imine (?C[dbnd]N?) linkers in COF-LZU1 provides materials with ultrahigh iodine vapor uptake by inducing the charge-transfer interactions to transform adsorbed iodine molecules into polyiodide anions. However, the combined π-conjugated structure in TpPa-1 shows no obvious effect on iodine adsorption enhancement. Hence, this study can provide a guidance for the design and construction of ultrahigh-capacity iodine adsorbents.
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.
The microwave-assisted solvothermal synthesis of a crystalline two-dimensional covalent organic framework with high CO2 capacity
Wei, Hao,Chai, Shuangzhi,Hu, Nantao,Yang, Zhi,Wei, Liangming,Wang, Lin
, p. 12178 - 12181 (2015)
We report the synthesis of a two-dimensional enamine-linked covalent organic framework (COF) using a rapid microwave-assisted solvothermal method in significantly less time and high yield under a relatively low temperature. This COF was found to have a high crystallinity, high stability, high BET surface area, and a high CO2 capacity and adsorption selectivity of CO2/N2.
