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1.
Lei Guo Shang Jia Christian S. Diercks Xuejing Yang Sultan A. Alshmimri Omar M. Yaghi 《Angewandte Chemie (International ed. in English)》2020,59(5):2023-2027
Three new post‐synthetic modification reactions, namely amidation, esterification, and thioesterification, were demonstrated on a novel highly crystalline two‐dimensional covalent organic framework (COF), COF‐616, bearing pre‐installed carboxyl groups. The strategy can be used to introduce a large variety of functional groups into COFs and the modifications can be carried out under mild reaction conditions, with high yields, and an easy work‐up protocol. As a proof of concept, various chelating functionalities were successfully incorporated into COF‐616 to yield a family of adsorbents for efficient removal of several contaminants in the water. 相似文献
2.
Direct Solar‐to‐Electrochemical Energy Storage in a Functionalized Covalent Organic Framework
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Dr. Jiangquan Lv Dr. Yan‐Xi Tan Dr. Jiafang Xie Rui Yang Dr. Muxin Yu Shanshan Sun Prof. Ming‐De Li Prof. Daqiang Yuan Prof. Yaobing Wang 《Angewandte Chemie (International ed. in English)》2018,57(39):12716-12720
A covalent organic framework integrating naphthalenediimide and triphenylamine units (NT‐COF) is presented. Two‐dimensional porous nanosheets are packed with a high specific surface area of 1276 m2 g?1. Photo/electrochemical measurements reveal the ultrahigh efficient intramolecular charge transfer from the TPA to the NDI and the highly reversible electrochemical reaction in NT‐COF. There is a synergetic effect in NT‐COF between the reversible electrochemical reaction and intramolecular charge transfer with enhanced solar energy efficiency and an accelerated electrochemical reaction. This synergetic mechanism provides the key basis for direct solar‐to‐electrochemical energy conversion/storage. With the NT‐COF as the cathode materials, a solar Li‐ion battery is realized with decreased charge voltage (by 0.5 V), increased discharge voltage (by 0.5 V), and extra 38.7 % battery efficiency. 相似文献
3.
A Molecular Pillar Approach To Grow Vertical Covalent Organic Framework Nanosheets on Graphene: Hybrid Materials for Energy Storage
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Dr. Jinhua Sun Alexey Klechikov Calin Moise Dr. Mariana Prodana Prof. Marius Enachescu Prof. Alexandr V. Talyzin 《Angewandte Chemie (International ed. in English)》2018,57(4):1034-1038
Hybrid 2D–2D materials composed of perpendicularly oriented covalent organic frameworks (COFs) and graphene were prepared and tested for energy storage applications. Diboronic acid molecules covalently attached to graphene oxide (GO) were used as nucleation sites for directing vertical growth of COF‐1 nanosheets (v‐COF‐GO). The hybrid material has a forest of COF‐1 nanosheets with a thickness of 3 to 15 nm in edge‐on orientation relative to GO. The reaction performed without molecular pillars resulted in uncontrollable growth of thick COF‐1 platelets parallel to the surface of GO. The v‐COF‐GO was converted into a conductive carbon material preserving the nanostructure of precursor with ultrathin porous carbon nanosheets grafted to graphene in edge‐on orientation. It was demonstrated as a high‐performance electrode material for supercapacitors. The molecular pillar approach can be used for preparation of many other 2D‐2D materials with control of their relative orientation. 相似文献
4.
Rufan Chen Ji‐Long Shi Yuan Ma Guiqing Lin Xianjun Lang Cheng Wang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(19):6496-6500
The construction of stable covalent organic frameworks (COFs) for various applications is highly desirable. Herein, we report the synthesis of a novel two‐dimensional (2D) porphyrin‐based sp2 carbon‐conjugated COF (Por‐sp2c‐COF), which adopts an eclipsed AA stacking structure with a Brunauer—Emmett—Teller surface area of 689 m2 g?1. Owing to the C=C linkages, Por‐sp2c‐COF shows a high chemical stability under various conditions, even under harsh conditions such as 9 m HCl and 9 m NaOH solutions. Interestingly, Por‐sp2c‐COF can be used as a metal‐free heterogeneous photocatalyst for the visible‐light‐induced aerobic oxidation of amines to imines. More importantly, in comparison to imine‐linked Por‐COF, the inherent structure of Por‐sp2c‐COF equips it with several advantages as a photocatalyst, including reusability and high photocatalytic performance. This clearly demonstrates that sp2 carbon‐linked 2D COFs can provide an interesting platform for heterogeneous photocatalysis. 相似文献
5.
Amitava Acharjya Pradip Pachfule Jrme Roeser Franz‐Josef Schmitt Arne Thomas 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(42):15007-15012
Two 2D covalent organic frameworks (COFs) linked by vinylene (?CH=CH?) groups (V‐COF‐1 and V‐COF‐2) are synthesized by exploiting the electron deficient nature of the aromatic s‐triazine unit of C3‐symmetric 2,4,6‐trimethyl‐s‐triazine (TMT). The acidic terminal methyl hydrogens of TMT can easily be abstracted by a base, resulting in a stabilized carbanion, which further undergoes aldol condensation with multitopic aryl aldehydes to be reticulated into extended crystalline frameworks (V‐COFs). Both V‐COF‐1 (with terepthalaldehyde (TA)) and V‐COF‐2 (with 1,3,5‐tris(p‐formylphenyl)benzene (TFPB)) are polycrystalline and exhibit permanent porosity and BET surface areas of 1341 m2 g?1 and 627 m2 g?1, respectively. Owing to the close proximity (3.52 Å) of the pre‐organized vinylene linkages within adjacent 2D layers stacked in eclipsed fashion, [2+2] photo‐cycloadditon in V‐COF‐1 formed covalent crosslinks between the COF layers. 相似文献
6.
Postsynthetic Functionalization of Three‐Dimensional Covalent Organic Frameworks for Selective Extraction of Lanthanide Ions
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Qiuyu Lu Yunchao Ma Hui Li Xinyu Guan Yusran Yusran Prof. Ming Xue Prof. Qianrong Fang Prof. Yushan Yan Prof. Shilun Qiu Prof. Valentin Valtchev 《Angewandte Chemie (International ed. in English)》2018,57(21):6042-6048
Chemical functionalization of covalent organic frameworks (COFs) is critical for tuning their properties and broadening their potential applications. However, the introduction of functional groups, especially to three‐dimensional (3D) COFs, still remains largely unexplored. Reported here is a general strategy for generating a 3D carboxy‐functionalized COF through postsynthetic modification of a hydroxy‐functionalized COF, and for the first time exploration of the 3D carboxy‐functionalized COF in the selective extraction of lanthanide ions. The obtained COF shows high crystallinity, good chemical stability, and large specific surface area. Furthermore, the carboxy‐functionalized COF displays high metal loading capacities together with excellent adsorption selectivity for Nd3+ over Sr2+ and Fe3+ as confirmed by the Langmuir adsorption isotherms and ideal adsorbed solution theory (IAST) calculations. This study not only provides a strategy for versatile functionalization of 3D COFs, but also opens a way to their use in environmentally related applications. 相似文献
7.
Weiben Chen Lei Wang Daize Mo Feng He Zhilin Wen Xiaojun Wu Hangxun Xu Long Chen 《Angewandte Chemie (International ed. in English)》2020,59(39):16902-16909
Two‐dimensional covalent organic frameworks (2D COFs), an emerging class of crystalline porous polymers, have been recognized as a new platform for efficient solar‐to‐hydrogen energy conversion owing to their pre‐designable structures and tailor‐made functions. Herein, we demonstrate that slight modulation of the chemical structure of a typical photoactive 2D COF (Py‐HTP‐BT‐COF) via chlorination (Py‐ClTP‐BT‐COF) and fluorination (Py‐FTP‐BT‐COF) can lead to dramatically enhanced photocatalytic H2 evolution rates (HER=177.50 μmol h?1 with a high apparent quantum efficiency (AQE) of 8.45 % for Py‐ClTP‐BT‐COF). Halogen modulation at the photoactive benzothiadiazole moiety can efficiently suppress charge recombination and significantly reduce the energy barrier associated with the formation of H intermediate species (H*) on polymer surface. Our findings provide new prospects toward design and synthesis of highly active organic photocatalysts toward solar‐to‐chemical energy conversion. 相似文献
8.
An Azine‐Linked Covalent Organic Framework: Synthesis,Characterization and Efficient Gas Storage
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Zhongping Li Yongfeng Zhi Xiao Feng Xuesong Ding Yongcun Zou Prof. Xiaoming Liu Prof. Ying Mu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(34):12079-12084
A azine‐linked covalent organic framework, COF‐JLU2, was designed and synthesized by condensation of hydrazine hydrate and 1,3,5‐triformylphloroglucinol under solvothermal conditions for the first time. The new covalent organic framework material combines permanent micropores, high crystallinity, good thermal and chemical stability, and abundant heteroatom activated sites in the skeleton. COF‐JLU2 possesses a moderate BET surface area of over 410 m2 g?1 with a pore volume of 0.56 cm3 g?1. Specifically, COF‐JLU2 displays remarkable carbon dioxide uptake (up to 217 mg g?1) and methane uptake (38 mg g?1) at 273 K and 1 bar, as well as high CO2/N2 (77) selectivity. Furthermore, we further highlight that it exhibits a higher hydrogen storage capacity (16 mg g?1) than those of reported COFs at 77 K and 1 bar. 相似文献
9.
Surface‐Confined Single‐Layer Covalent Organic Framework on Single‐Layer Graphene Grown on Copper Foil
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Lirong Xu Xin Zhou Prof. Wei Quan Tian Teng Gao Yan Feng Zhang Prof. Shengbin Lei Prof. Zhong Fan Liu 《Angewandte Chemie (International ed. in English)》2014,53(36):9564-9568
The integration of 2D covalent organic frameworks (COFs) with atomic thickness with graphene will lead to intriguing two‐dimensional materials. A surface‐confined covalently bonded Schiff base network was prepared on single‐layer graphene grown on copper foil and the dynamic reaction process was investigated with scanning tunneling microscopy. DFT simulations provide an understanding of the electronic structures and the interactions between the surface COF and graphene. Strong coupling between the surface COF and graphene was confirmed by the dispersive bands of the surface COF after interaction with graphene, and also by the experimental observation of tunneling condition dependent contrast of the surface COF. 相似文献
10.
A Covalent Organic Framework–Cadmium Sulfide Hybrid as a Prototype Photocatalyst for Visible‐Light‐Driven Hydrogen Production
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Dr. Jayshri Thote Harshitha Barike Aiyappa Aparna Deshpande Prof. Dr. David Díaz Díaz Dr. Sreekumar Kurungot Dr. Rahul Banerjee 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(48):15961-15965
CdS nanoparticles were deposited on a highly stable, two‐dimensional (2D) covalent organic framework (COF) matrix and the hybrid was tested for photocatalytic hydrogen production. The efficiency of CdS‐COF hybrid was investigated by varying the COF content. On the introduction of just 1 wt % of COF, a dramatic tenfold increase in the overall photocatalytic activity of the hybrid was observed. Among the various hybrids synthesized, that with 10 wt % COF, named CdS‐COF (90:10), was found to exhibit a steep H2 production amounting to 3678 μmol h?1 g?1, which is significantly higher than that of bulk CdS particles (124 μmol h?1 g?1). The presence of a π‐conjugated backbone, high surface area, and occurrence of abundant 2D hetero‐interface highlight the usage of COF as an effective support for stabilizing the generated photoelectrons, thereby resulting in an efficient and high photocatalytic activity. 相似文献
11.
Yi Meng Yi Luo Ji‐Long Shi Huimin Ding Xianjun Lang Wei Chen Anmin Zheng Junliang Sun Cheng Wang 《Angewandte Chemie (International ed. in English)》2020,59(9):3624-3629
The construction of 2D and 3D covalent organic frameworks (COFs) from functional moieties for desired properties has gained much attention. However, the influence of COFs dimensionality on their functionalities, which can further assist in COF design, has never been explored. Now, by selecting designed precursors and topology diagrams, 2D and 3D porphyrinic COFs (2D‐PdPor‐COF and 3D‐PdPor‐COF) are synthesized. By model building and Rietveld refinement of powder X‐ray diffraction, 2D‐PdPor‐COF crystallizes as 2D sheets while 3D‐PdPor‐COF adopts a five‐fold interpenetrated pts topology. Interestingly, compared with 2D‐PdPor‐COF, 3D‐PdPor‐COF showed interesting properties, including 1) higher CO2 adsorption capacity; 2) better photocatalytic performance; and 3) size‐selective photocatalysis. Based on this study, we believe that with the incorporation of functional moieties, the dimensionality of COFs can definitely influence their functionalities. 相似文献
12.
Rational Design of MOF/COF Hybrid Materials for Photocatalytic H2 Evolution in the Presence of Sacrificial Electron Donors
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Dr. Feng‐Ming Zhang Jing‐Li Sheng Prof. Zhao‐Di Yang Prof. Xiao‐Jun Sun Hong‐Liang Tang Meng Lu Hong Dong Feng‐Cui Shen Dr. Jiang Liu Prof. Ya‐Qian Lan 《Angewandte Chemie (International ed. in English)》2018,57(37):12106-12110
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. The resulting hierarchical porous hybrid materials show efficient photocatalytic H2 evolution under visible light irradiation. Especially, NH2‐UiO‐66/TpPa‐1‐COF (4:6) exhibits the maximum photocatalytic H2 evolution rate of 23.41 mmol g?1 h?1 (with the TOF of 402.36 h?1), which is approximately 20 times higher than that of the parent TpPa‐1‐COF and the best performance photocatalyst for H2 evolution among various MOF‐ and COF‐based photocatalysts. 相似文献
13.
Tomoki Shirokura Dr. Tomoki Hirohata Dr. Kosuke Sato Dr. Elena Villani Kazuyasu Sekiya Yu-An Chien Dr. Tomoyuki Kurioka Dr. Ryoyu Hifumi Prof. Dr. Yoshiyuki Hattori Prof. Dr. Masato Sone Prof. Dr. Ikuyoshi Tomita Prof. Dr. Shinsuke Inagi 《Angewandte Chemie (International ed. in English)》2023,62(40):e202307343
Imine-based covalent organic frameworks (COFs) are crystalline porous materials with prospective uses in various devices. However, general bulk synthetic methods usually produce COFs as powders that are insoluble in most of the common organic solvents, arising challenges for the subsequent molding and fixing of these materials on substrates. Here, we report a novel synthetic methodology that utilizes an electrogenerated acid (EGA), which is produced at an electrode surface by electrochemical oxidation of a suitable precursor, acting as an effective Brønsted acid catalyst for imine bond formation from the corresponding amine and aldehyde monomers. Simultaneously, it provides the corresponding COF film deposited on the electrode surface. The COF structures obtained with this method exhibited high crystallinities and porosities, and the film thickness could be controlled. Furthermore, such process was applied for the synthesis of various imine-based COFs, including a three-dimensional (3D) COF structure. 相似文献
14.
Dr. Qiang Gao Linyi Bai Dr. Yongfei Zeng Dr. Peng Wang Dr. Xiaojing Zhang Prof. Ruqiang Zou Prof. Yanli Zhao 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(47):16818-16822
Covalent organic frameworks (COFs) are periodic two‐ or three‐dimensional polymeric networks with high surface areas, low density, and designed structures. Because COFs are normally prepared based on reversible formation of covalent bonds with relatively weak stability, their structures can be easily broken or damaged due to changes in the surrounding environment. Thus, developing strategies to realize the reconstruction of COFs in order to extend their usage lifetime is crucial for practical applications. In addition, exploring the kinetics of COF growth under varied reaction conditions is important for better understanding the nucleation and growth processes of COFs. In this work, the reformation mechanism of an imine‐based COF using an ex situ characterization method was investigated, disclosing an interesting COF reconstruction progress from disorder to order. The present study shows the regeneration ability of COFs, and the developed method could be generalized for broader use in the field. 相似文献
15.
Huimin Ding Yonghai Li Hui Hu Dr. Yimeng Sun Jianguo Wang Caixing Wang Prof. Dr. Cheng Wang Dr. Guanxin Zhang Prof. Dr. Baoshan Wang Prof. Dr. Wei Xu Prof. Dr. Deqing Zhang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(45):14614-14618
Two‐dimensional covalent organic frameworks (2D COFs) provide a unique platform for the molecular design of electronic and optoelectronic materials. Here, the synthesis and characterization of an electroactive COF containing the well‐known tetrathiafulvalene (TTF) unit is reported. The TTF‐COF crystallizes into 2D sheets with an eclipsed AA stacking motif, and shows high thermal stability and permanent porosity. The presence of TTF units endows the TTF‐COF with electron‐donating ability, which is characterized by cyclic voltammetry. In addition, the open frameworks of TTF‐COF are amenable to doping with electron acceptors (e.g., iodine), and the conductivity of TTF‐COF bulk samples can be improved by doping. Our results open up a reliable route for the preparation of well‐ordered conjugated TTF polymers, which hold great potential for applications in fields from molecular electronics to energy storage. 相似文献
16.
Ahmed F. M. El‐Mahdy Ying‐Hui Hung Tharwat Hassan Mansoure Hsiao‐Hua Yu Tao Chen Shiao‐Wei Kuo 《化学:亚洲杂志》2019,14(9):1429-1435
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‐formylphenyl)triazine (TPT‐3CHO) and 2,5‐diaminohydroquinone dihydrochloride (DAHQ‐2HCl). The synthesized COF exhibited extremely high crystallinity, a high surface area (ca. 1855 m2 g?1), and ultrahigh thermal stability. Interestingly, a time‐dependent study of the formation of the hollow microtubular COF having a sponge‐like shell revealed a transformation from initial ribbon‐like crystallites into a hollow tubular structure, and confirmed that the hollow nature of the synthesized COF was controlled by inside‐out Ostwald ripening, while the non‐interaction of the crystallites on the outer surface was responsible for the sponge‐like surface of the tubules. This COF exhibited significant supercapacitor performance: a high specific capacitance of 256 F g?1 at a current density of 0.5 A g?1, excellent cycling stability (98.8 % capacitance retention over 1850 cycles), and a high energy density of 43 Wh kg?1. Such hollow structural COFs with sponge‐like shells appear to have great potential for use as high‐performance supercapacitors in energy storage applications. 相似文献
17.
Ignacio Romero‐Muiz Andreas Mavrandonakis Pablo Albacete Alicia Vega Valrie Briois Flix Zamora Ana E. Platero‐Prats 《Angewandte Chemie (International ed. in English)》2020,59(31):13013-13020
Layered covalent organic frameworks (2D‐COFs), composed of reversible imine linkages and accessible pores, offer versatility for chemical modifications towards the development of catalytic materials. Nitrogen‐enriched COFs are good candidates for binding Pd species. Understanding the local structure of reacting Pd sites bonded to the COF pores is key to rationalize interactions between active sites and porous surfaces. By combining advanced synchrotron characterization methods with periodic computational DFT modeling, the precise atomic structure of catalytic Pd sites attached to local defects is resolved within an archetypical imine‐linked 2D‐COF. This material was synthesized using an in situ method as a gel, under which imine hydrolysis and metalation reactions are coupled. Local defects formed in situ within imine‐linked 2D‐COF materials are highly reactive towards Pd metalation, resulting in active materials for Suzuki–Miyaura cross‐coupling reactions. 相似文献
18.
Direct On‐Surface Patterning of a Crystalline Laminar Covalent Organic Framework Synthesized at Room Temperature
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Alejandro de la Peña Ruigómez David Rodríguez‐San‐Miguel Dr. Kyriakos C. Stylianou Dr. Massimiliano Cavallini Dr. Denis Gentili Dr. Fabiola Liscio Prof. Silvia Milita Dr. Otello Maria Roscioni Dr. Maria Luisa Ruiz‐González Carlos Carbonell Prof. Daniel Maspoch Dr. Rubén Mas‐Ballesté Dr. José Luis Segura Dr. Félix Zamora 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(30):10666-10670
We report herein an efficient, fast, and simple synthesis of an imine‐based covalent organic framework (COF) at room temperature (hereafter, RT‐COF‐1 ). RT‐COF‐1 shows a layered hexagonal structure exhibiting channels, is robust, and is porous to N2 and CO2. The room‐temperature synthesis has enabled us to fabricate and position low‐cost micro‐ and submicropatterns of RT‐COF‐1 on several surfaces, including solid SiO2 substrates and flexible acetate paper, by using lithographically controlled wetting and conventional ink‐jet printing. 相似文献
19.
Yanming Zhao Wenhao Dai Yunlei Peng Zheng Niu Qi Sun Chuan Shan Hui Yang Gaurav Verma Lukasz Wojtas Daqiang Yuan Zhenjie Zhang Haifeng Dong Xueji Zhang Bao Zhang Yaqing Feng Shengqian Ma 《Angewandte Chemie (International ed. in English)》2020,59(11):4354-4359
Herein, for the first time, we present the successful synthesis of a novel two‐dimensional corrole‐based covalent organic framework (COF) by reacting the unusual approximately T‐shaped 5,10,15‐tris(p‐aminophenyl)corrole H3TPAPC with terephthalaldehyde, which adopts desymmetrized hcb topology and consists of a staggered AB stacking structure with elliptical pores. The resultant corrole‐based COF, TPAPC‐COF , exhibits high crystallinity and excellent chemical stability. The combination of extended π‐conjugated backbone and interlayer noncovalent π–π interactions endows TPAPC‐COF with excellent absorption capability in the entire visible‐light and even near‐infrared regions. Moreover, this work suggests the promise of TPAPC‐COF as a new class of photoactive material for efficient singlet‐oxygen generation with potential photodynamic therapy application as demonstrated by in vitro anticancer studies. 相似文献