- Perylene-based covalent organic frameworks for acid vapor sensing
-
Traditionally, the properties and functions of covalent organic frameworks (COFs) are defined by their constituting building blocks, while the chemical bonds that connect the individual subunits have not attracted much attention as functional components of the final material. We have developed a new series of dual-pore perylene-based COFs and demonstrated that their imine bonds can be protonated reversibly, causing significant protonation-induced color shifts toward the near-infrared, while the structure and crystallinity of the frameworks are fully retained. Thin films of these COFs are highly sensitive colorimetric acid vapor sensors with a detection limit as low as 35 μg L-1 and a response range of at least 4 orders of magnitude. Since the acidochromism in our COFs is a cooperative phenomenon based on electronically coupled imines, the COFs can be used to determine simultaneously the concentration and protonation strength of nonaqueous acid solutions, in which pH electrodes are not applicable, and to distinguish between different acids. Including the imine bonds as function-determining constituents of the framework provides an additional handle for constructing multifunctional COFs and extending the range of their possible applications.
- Ascherl, Laura,Evans, Emrys W.,Gorman, Jeffrey,Orsborne, Sarah,Bessinger, Derya,Bein, Thomas,Friend, Richard H.,Auras, Florian
-
-
Read Online
- Synthesis of Stable Thiazole-Linked Covalent Organic Frameworks via a Multicomponent Reaction
-
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.
-
-
Read Online
- COVALENT ORGANIC FRAMEWORKS AND APPLICATIONS AS PHOTOCATALYSTS
-
Described herein are covalent organic frameworks. The covalent organic frameworks have unique structural and physical properties, which lends them to be versatile in a number of different applications and uses. In one aspect, the covalent organic frameworks are composed of a plurality of fused aromatic groups and electron-deficient chromophores. The covalent organic frameworks are useful as photocatalysts in a number of different applications.
- -
-
-
- A Comparative Study of Redox-Active Dithiafulvenyl-Functionalized 1,3,6,8-Tetraphenylpyrene Derivatives
-
A series of 1,3,6,8-tetraphenylpyrene (TPPy) derivatives substituted with redox-active 1,4-dithiafulvenyl (DTF) groups was synthesized and characterized. The conformational properties of these DTF-TPPys and their TPPy precursors were assessed by X-ray single-crystal and nuclear magnetic resonance analyses. Their electronic and redox properties were examined by ultraviolet-visible absorption, fluorescence, and cyclic voltammetric analyses. The DTF substitution was found to strongly modify the absorption, emission, and electrochemical properties, while detailed effects can be linked to substitution patterns and alkyl side chains attached to the DTF groups. Furthermore, the DTF-TPPy derivatives showed sensitivity to acids; in particular, the vinylic proton of DTF group could undergo efficient proton/deuterium exchange with D2O in an acidic medium.
- Shahrokhi, Farshid,Abdollahi, Maryam F.,Zhao, Yuming
-
p. 12723 - 12736
(2021/09/28)
-
- Exploitation of two-dimensional conjugated covalent organic frameworks based on tetraphenylethylene with bicarbazole and pyrene units and applications in perovskite solar cells
-
In this work, two-dimensional conjugated covalent organic frameworks (2D-COF) based on a building block of tetraphenylethylene are successfully developed. Bicarbazole and pyrene moieties are respectively coupled with 4,4′,4′′,4′′′-(ethane-1,1,2,2-tetrayl)tetranilino (ETTA)via[4 + 4] solvothermal condensation conditions of 3,3′,6,6′-tetraformyl-9,9′-bicarbazole (Car-4CHO) and 1,3,6,8-tetrakis(4-formylphenyl)pyrene (TFPPy) to affordCar-ETTAandTFPPy-ETTACOFs. According to thermogravimetric analysis (TGA), powder X-ray diffraction (PXRD), and N2adsorption and desorption measurements, bothCar-ETTAandTFPPy-ETTACOFs exhibit excellent thermal stability, highly crystalline structure, and high specific surface area, respectively. These findings are supported by force field andab initiocalculations. Furthermore, successful applications of these COFs in perovskite solar cells (PVSCs) are demonstrated owing to their well-conjugated properties and π-π interactions. While serving as interlayers in the devices, these COFs could effectively promote the interfacial charge dynamic to further optimize the resulting performance. Besides, certain interaction between COFs and perovskite also leads to an improved morphology and crystallinity of the perovskite layer, presenting defect passivation capability. As a result, we show that the performance of the COF-modified PVSC could be improved from 17.40 to 19.80%.
- Chueh, Chu-Chen,EL-Mahdy, Ahmed F. M.,Kuo, Shiao-Wei,Lüder, Johann,Lee, Chia-Chen,Li, Zhen,Mohamed, Mohamed Gamal,Yu, Ming-Hsuan,Zhu, Zonglong
-
p. 11448 - 11459
(2020/06/17)
-
- Ultrastable tetraphenyl-: P -phenylenediamine-based covalent organic frameworks as platforms for high-performance electrochemical supercapacitors
-
In this study we synthesized two tetraphenyl-p-phenylenediamine-based covalent organic frameworks (TPPDA-TPPyr and TPPDA-TPTPE COFs) for potential use in high-performance electrochemical supercapacitors. This excellent performance arose from their structures containing redox-active triphenylamine derivatives and their high surface areas.
- El-Mahdy, Ahmed F. M.,Mohamed, Mohamed Gamal,Mansoure, Tharwat Hassan,Yu, Hsiao-Hua,Chen, Tao,Kuo, Shiao-Wei
-
p. 14890 - 14893
(2019/12/24)
-
- Conversion of Imine to Oxazole and Thiazole Linkages in Covalent Organic Frameworks
-
Imine-linked ILCOF-1 based on 1,4-phenylenediamine and 1,3,6,8-tetrakis(4-formylphenyl)pyrene was converted through consecutive linker substitution and oxidative cyclization to two isostructural covalent organic frameworks (COFs), having thiazole and oxazole linkages. The completeness of the conversion was assessed by infrared and solid-state NMR spectroscopies, and the crystallinity of the COFs was confirmed by powder X-ray diffraction. Furthermore, the azole-linked COFs remain porous, as shown by nitrogen sorption experiments. The materials derived in this way demonstrate increased chemical stability, relative to the imine-linked starting material. This constitutes a facile method for accessing COFs and linkages that are otherwise difficult to crystallize due to their inherently limited microscopic reversibility.
- Waller, Peter J.,Alfaraj, Yasmeen S.,Diercks, Christian S.,Jarenwattananon, Nanette N.,Yaghi, Omar M.
-
supporting information
p. 9099 - 9103
(2018/08/03)
-
- Designed synthesis of porphyrin-based two-dimensional covalent organic frameworks with highly ordered structures
-
Porphyrins are representative functional π-systems; synthesizing their highly ordered structures is an established goal in chemistry. Here, we report the designed synthesis of a series of porphyrin-based covalent organic frameworks with highly ordered structures through polycondensation. The porphyrinbased frameworks exhibited high crystallinity, high porosity, and extended π-conjugation over the polyporphyrin sheets.
- Chen, Xiong,Gao, Jia,Jiang, Donglin
-
supporting information
p. 1257 - 1259
(2015/09/22)
-