- Molecularly Defined Nanostructures Based on a Novel AAA-DDD Triple Hydrogen-Bonding Motif
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A facile and flexible method for the synthesis of a new AAA-DDD triple hydrogen-bonding motif is described. Polytopic supramolecular building blocks with precisely oriented AAA and DDD groups are thus accessible in few steps. These building blocks were used for the assembly of large macrocycles featuring four AAA-DDD interactions and a macrobicyclic complex with a total of six AAA-DDD interactions.
- Papmeyer, Marcus,Vuilleumier, Clément A.,Pavan, Giovanni M.,Zhurov, Konstantin O.,Severin, Kay
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- Amine-Linked Covalent Organic Frameworks as a Platform for Postsynthetic Structure Interconversion and Pore-Wall Modification
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Covalent organic frameworks have emerged as a powerful synthetic platform for installing and interconverting dedicated molecular functions on a crystalline polymeric backbone with atomic precision. Here, we present a novel strategy to directly access amine-linked covalent organic frameworks, which serve as a scaffold enabling pore-wall modification and linkage-interconversion by new synthetic methods based on Leuckart-Wallach reduction with formic acid and ammonium formate. Frameworks connected entirely by secondary amine linkages, mixed amine/imine bonds, and partially formylated amine linkages are obtained in a single step from imine-linked frameworks or directly from corresponding linkers in a one-pot crystallization-reduction approach. The new, 2D amine-linked covalent organic frameworks, rPI-3-COF, rTTI-COF, and rPy1P-COF, are obtained with high crystallinity and large surface areas. Secondary amines, installed as reactive sites on the pore wall, enable further postsynthetic functionalization to access tailored covalent organic frameworks, with increased hydrolytic stability, as potential heterogeneous catalysts.
- Grunenberg, Lars,Savasci, G?kcen,Terban, Maxwell W.,Duppel, Viola,Moudrakovski, Igor,Etter, Martin,Dinnebier, Robert E.,Ochsenfeld, Christian,Lotsch, Bettina V.
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p. 3430 - 3438
(2021/04/07)
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- Synthesis of Ionic Vinylene-Linked Covalent Organic Frameworks through Quaternization-Activated Knoevenagel Condensation
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We developed a simple approach to synthesizing ionic vinylene-linked two-dimensional covalent organic frameworks (COFs) through a quaternization-promoted Knoevenagel condensation at three aromatic methyl carbon atoms of N-ethyl-2,4,6-trimethylpyridinium h
- Bi, Shuai,Chen, Jie-Sheng,Jiang, Biao,Meng, Fancheng,Sun, Zuobang,Wu, Dongqing,Zhang, Fan
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p. 13614 - 13620
(2021/05/12)
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- A hydrophilic covalent organic framework for photocatalytic oxidation of benzylamine in water
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The highly hydrophilic COF material (TFPT-BMTH) was constructed by pore surface functionalizing strategy, and exhibited excellent porosity, high crystallinity, and good thermal and chemical stability. The resulting COF exhibits significant catalytic activity and recyclability together with environmental benignity in photocatalytic oxidation of benzylamine in water under ambient conditions.
- Liu, Ziqian,Su, Qing,Ju, Pengyao,Li, Xiaodong,Li, Guanghua,Wu, Qiaolin,Yang, Bing
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p. 766 - 769
(2020/01/29)
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- Linkage Engineering by Harnessing Supramolecular Interactions to Fabricate 2D Hydrazone-Linked Covalent Organic Framework Platforms toward Advanced Catalysis
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Covalent organic frameworks (COFs) are an emerging class of crystalline porous polymers with tailor-made structures and functionalities. To facilitate their utilization for advanced applications, it is crucial to develop a systematic approach to control the properties of COFs, including the crystallinity, stability, and functionalities. However, such an integrated design is challenging to achieve. Herein, we report supramolecular strategy-based linkage engineering to fabricate a versatile 2D hydrazone-linked COF platform for the coordination of different transition metal ions. Intra- and intermolecular hydrogen bonding as well as electrostatic interactions in the antiparallel stacking mode were first utilized to obtain two isoreticular COFs, namely COF-DB and COF-DT. On account of suitable nitrogen sites in COF-DB, the further metalation of COF-DB was accomplished upon the complexation with seven divalent transition metal ions M(II) (M = Mn, Co, Ni, Cu, Zn, Pd, and Cd) under mild conditions. The resultant M/COF-DB exhibited extended π-conjugation, improved crystallinity, enhanced stability, and additional functionalities as compared to the parent COF-DB. Furthermore, the dynamic nature of the coordination bonding in M/COF-DB allows for the easy replacement of metal ions through a postsynthetic exchange. In particular, the coordination mode in Pd/COF-DB endows it with excellent catalytic activity and cyclic stability as a heterogeneous catalyst for the Suzuki-Miyaura cross-coupling reaction, outperforming its amorphous counterparts and Pd/COF-DT. This strategy provides an opportunity for the construction of 2D COFs with designable functions and opens an avenue to create COFs as multifunctional systems.
- Qian, Cheng,Zhou, Weiqiang,Qiao, Jingsi,Wang, Dongdong,Li, Xing,Teo, Wei Liang,Shi, Xiangyan,Wu, Hongwei,Di, Jun,Wang, Hou,Liu, Guofeng,Gu, Long,Liu, Jiawei,Feng, Lili,Liu, Yuchuan,Quek, Su Ying,Loh, Kian Ping,Zhao, Yanli
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supporting information
p. 18138 - 18149
(2020/11/02)
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- Thermal conversion of triazine-based covalent organic frameworks to nitrogen-doped nanoporous carbons and their capacitor performance
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Nanoporous carbons with well-defined pore structures are promising for advanced energy applications. Nitrogen-doped porous carbons were prepared via direct carbonization of a triazine-based covalent organic framework (TACOF1) that acts as both intrinsic t
- Fujigaya, Tsuyohiko,Kim, Gayoung,Shiraki, Tomohiro
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p. 414 - 420
(2020/05/28)
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- Synthesis of Stable Thiazole-Linked Covalent Organic Frameworks via a Multicomponent Reaction
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The development of robust synthetic routes to stable covalent organic frameworks (COFs) is important to broaden the range of applications for these materials. We report here a simple and efficient three-component assembly reaction between readily available aldehydes, amines, and elemental sulfur via a C-H functionalization and oxidative annulation under transition-metal-free conditions. Five thiazole-linked COFs (TZ-COFs) were synthesized using this method. These materials showed high levels of crystallinity, high specific surface areas, and excellent physicochemical stability. The photocatalytic applications of TZ-COFs were investigated, and TZ-COF-4 gave high sacrificial hydrogen evolution rates from water (up to 4296 μmol h-1 g-1 under visible light irradiation) coupled with high stability and recyclability, with sustained hydrogen evolution for 50 h.
- Wang, Kewei,Jia, Zhifang,Bai, Yang,Wang, Xue,Hodgkiss, Sophie E.,Chen, Linjiang,Chong, Samantha Y.,Wang, Xiaoyan,Yang, Haofan,Xu, Yongjie,Feng, Feng,Ward, John W.,Cooper, Andrew I.
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supporting information
p. 11131 - 11138
(2020/07/13)
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- A Hollow Microtubular Triazine- and Benzobisoxazole-Based Covalent Organic Framework Presenting Sponge-Like Shells That Functions as a High-Performance Supercapacitor
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In this paper we report the construction of a hollow microtubular triazine- and benzobisoxazole-based covalent organic framework (COF) presenting a sponge-like shell through a template-free [3+2] condensation of the planar molecules 2,4,6-tris(4-formylphe
- El-Mahdy, Ahmed F. M.,Hung, Ying-Hui,Mansoure, Tharwat Hassan,Yu, Hsiao-Hua,Chen, Tao,Kuo, Shiao-Wei
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supporting information
p. 1429 - 1435
(2019/03/21)
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- Strategic design of triphenylamine- and triphenyltriazine-based two-dimensional covalent organic frameworks for CO2 uptake and energy storage
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Hexagonally ordered covalent organic frameworks (COFs) are interesting new crystalline porous materials that have massive potential for application in gas storage. Herein, we report the synthesis of two series of two-dimensional hexagonally ordered COFs - TPA-COFs and TPT-COFs - through one-pot polycondensations of tris(4-aminophenyl)amine (TPA-3NH2) and 2,4,6-tris(4-aminophenyl)triazine (TPT-3NH2), respectively, with triarylaldehydes featuring different degrees of planarity, symmetry, and nitrogen content. All the synthesized COFs exhibited high crystallinity, large BET surface areas (up to 1747 m2 g-1), excellent thermal stability, and pore size distributions from 1.80 to 2.55 nm. The symmetry and planarity of the monomers strongly affected the degrees of crystallinity and the BET surface areas of the resultant COFs. In addition, these COFs displayed excellent CO2 uptake efficiencies of up to 65.65 and 92.38 mg g-1 at 298 and 273 K, respectively. The incorporation of the more planar and higher-nitrogen-content triaryltriazine unit into the backbones of the TPA-COFs and TPT-COFs enhanced the interactions with CO2, leading to higher CO2 uptakes. Moreover, the synthesized COFs exhibited electrochemical properties because of their conjugated structures containing redox-active triphenylamine groups. This study exposes the importance of considering the symmetry and planarity of the monomers when designing highly crystalline COFs; indeed, the structures of COFs can be tailored to vary their functionalities for specific applications.
- El-Mahdy, Ahmed F. M.,Kuo, Cheng-Han,Alshehri, Abdulmohsen,Young, Christine,Yamauchi, Yusuke,Kim, Jeonghun,Kuo, Shiao-Wei
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supporting information
p. 19532 - 19541
(2018/10/24)
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