Covalent organic frameworks (COFs), established as an emerging class of crystalline porous polymers with high surface area, structural diversity, and esignability, attract much interest and exhibit potential applica...Covalent organic frameworks (COFs), established as an emerging class of crystalline porous polymers with high surface area, structural diversity, and esignability, attract much interest and exhibit potential applications in catalysis. In this review, we summarize the use of COFs as a versatile platform to develop heterogeneous catalysts for a variety of chemical reactions. Catalytic COFs are categorized in accordance with the types of active sites, involving single functional active sites, bifunctional active sites, and metal nanoparticles (NPs) embedded in pores. Special emphasis is placed on the deliberate or incidental synthesis strategies, the stability, the heterogeneity, and the shape/size selectivity for COF catalysis. Moreover, a description of the application of COFs as photocatalysts and electrocatalysts is presented. Finally, the prospects of COFs in catalysis and remaining issues in this field are indicated.展开更多
Covalent organic frameworks(COFs),with two dimensional(2D-)or three dimensional(3D-)structures,have accessible open channels or nanopores,with uniform sizes ranging from angstroms to nanometers and have emerged as an ...Covalent organic frameworks(COFs),with two dimensional(2D-)or three dimensional(3D-)structures,have accessible open channels or nanopores,with uniform sizes ranging from angstroms to nanometers and have emerged as an excellent and promising platform for designing catalysts or catalyst carriers.Herein,a 2 D-COF grafted with a 1-alkyl-3-methylimidazolium-based ionic liquid(AMIMBr@H2 P-DHPh COF)on the channel walls was synthesized and utilized as a highly efficient heterogeneous catalyst for the chemical fixation of CO2 via a reaction with epoxides under solvent-free and co-catalyst-free conditions.The as-synthesized AMIMBr@H2 P-DHPh COF shows excellent catalytic activity in promoting the cycloaddition reactions between epoxide and CO2;the excellent catalytic activity was maintained for up to five cycles.Advantages like high porosity,functional versatility,easy modification of COFs,and high catalytic activity of ionic liquids,have been realized in a single material.展开更多
Kasha's exciton model proposes that T1 energy levels of organic compounds are insensitive to molecular aggregation and microenvironment change because of negligible small transition dipole moments of T1 states.Thi...Kasha's exciton model proposes that T1 energy levels of organic compounds are insensitive to molecular aggregation and microenvironment change because of negligible small transition dipole moments of T1 states.This model holds true in most organic systems till now.Here we report the fabrication of twisted organic phosphors with intramolecular charge transfer characters and flexible molecular structures.When doped into different organic matrices,the twisted phosphor adopts different conformation,exhibits distinct phosphorescence colors and T1 energy levels,which violates Kasha's exciton model in organic system.Given that the change of phosphorescence colors and maxima can be readily distinguished by human eyes and conventional instrument,the twisted phosphors would be exploited as a new type of molecular probe,which would exhibit potential application in optical sensing and stimuli-responsive systems.展开更多
基金supported by the National Natural Science Foundation of China (21473196, 21406215)the State Key Laboratory of Fine Chemicals, Dalian University of Technology (KF1415)the funding from Dalian Institute of Chemical Physics, Chinese Academy of Sciences (DICP_M201401)~~
文摘Covalent organic frameworks (COFs), established as an emerging class of crystalline porous polymers with high surface area, structural diversity, and esignability, attract much interest and exhibit potential applications in catalysis. In this review, we summarize the use of COFs as a versatile platform to develop heterogeneous catalysts for a variety of chemical reactions. Catalytic COFs are categorized in accordance with the types of active sites, involving single functional active sites, bifunctional active sites, and metal nanoparticles (NPs) embedded in pores. Special emphasis is placed on the deliberate or incidental synthesis strategies, the stability, the heterogeneity, and the shape/size selectivity for COF catalysis. Moreover, a description of the application of COFs as photocatalysts and electrocatalysts is presented. Finally, the prospects of COFs in catalysis and remaining issues in this field are indicated.
文摘Covalent organic frameworks(COFs),with two dimensional(2D-)or three dimensional(3D-)structures,have accessible open channels or nanopores,with uniform sizes ranging from angstroms to nanometers and have emerged as an excellent and promising platform for designing catalysts or catalyst carriers.Herein,a 2 D-COF grafted with a 1-alkyl-3-methylimidazolium-based ionic liquid(AMIMBr@H2 P-DHPh COF)on the channel walls was synthesized and utilized as a highly efficient heterogeneous catalyst for the chemical fixation of CO2 via a reaction with epoxides under solvent-free and co-catalyst-free conditions.The as-synthesized AMIMBr@H2 P-DHPh COF shows excellent catalytic activity in promoting the cycloaddition reactions between epoxide and CO2;the excellent catalytic activity was maintained for up to five cycles.Advantages like high porosity,functional versatility,easy modification of COFs,and high catalytic activity of ionic liquids,have been realized in a single material.
基金supports from National Natural Science Foundation of China(22175194)Shanghai Scientific and Technological Innovation Project(20QA1411600,20ZR1469200)+1 种基金Hundred Talents Program from Shanghai Institute of Organic Chemistry(Y121078)Pioneer Hundred Talents Program of Chinese Academy of Sciences(E320021),and Ningbo Natural Science Foundation(2023J243).
文摘Kasha's exciton model proposes that T1 energy levels of organic compounds are insensitive to molecular aggregation and microenvironment change because of negligible small transition dipole moments of T1 states.This model holds true in most organic systems till now.Here we report the fabrication of twisted organic phosphors with intramolecular charge transfer characters and flexible molecular structures.When doped into different organic matrices,the twisted phosphor adopts different conformation,exhibits distinct phosphorescence colors and T1 energy levels,which violates Kasha's exciton model in organic system.Given that the change of phosphorescence colors and maxima can be readily distinguished by human eyes and conventional instrument,the twisted phosphors would be exploited as a new type of molecular probe,which would exhibit potential application in optical sensing and stimuli-responsive systems.