scholarly journals Covalent Organic Frameworks: Synthesis, Properties and Applications—An Overview

Polymers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 970
Author(s):  
Tiago F. Machado ◽  
M. Elisa Silva Serra ◽  
Dina Murtinho ◽  
Artur J. M. Valente ◽  
Mu. Naushad
Keyword(s):  
Gas Adsorption ◽  
Pore Wall ◽  
Building Blocks ◽  
Pollutant Removal ◽  
Three Dimensions ◽  
Covalent Organic Frameworks ◽  
Vast Number ◽  
Microporous Polymers ◽  
Material Chemistry ◽  
Synthesis Properties

Covalent Organic Frameworks (COFs) are an exciting new class of microporous polymers with unprecedented properties in organic material chemistry. They are generally built from rigid, geometrically defined organic building blocks resulting in robust, covalently bonded crystalline networks that extend in two or three dimensions. By strategically combining monomers with specific structures and properties, synthesized COF materials can be fine-tuned and controlled at the atomic level, with unparalleled precision on intrapore chemical environment; moreover, the unusually high pore accessibility allows for easy post-synthetic pore wall modification after the COF is synthesized. Overall, COFs combine high, permanent porosity and surface area with high thermal and chemical stability, crystallinity and customizability, making them ideal candidates for a myriad of promising new solutions in a vast number of scientific fields, with widely varying applications such as gas adsorption and storage, pollutant removal, degradation and separation, advanced filtration, heterogeneous catalysis, chemical sensing, biomedical applications, energy storage and production and a vast array of optoelectronic solutions. This review attempts to give a brief insight on COF history, the overall strategies and techniques for rational COF synthesis and post-synthetic functionalization, as well as a glance at the exponentially growing field of COF research, summarizing their main properties and introducing the numerous technological and industrial state of the art applications, with noteworthy examples found in the literature.

Nitrogen-rich conjugated microporous polymers: impact of building blocks on porosity and gas adsorption

2015 ◽  
Vol 3 (42) ◽  
pp. 21185-21193 ◽  
Author(s):  
Xiaoyan Wang ◽  
Yang Zhao ◽  
Lingling Wei ◽  
Chong Zhang ◽  
Jia-Xing Jiang
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Building Block ◽  
Gas Adsorption ◽  
Building Blocks ◽  
Microporous Polymers ◽  
Conjugated Microporous Polymers

A series of nitrogen-rich conjugated microporous polymers has been designed and synthesized. The polymers produced from the rigid building block show an increased specific surface area up to 1146 m2 g−1 with a remarkable CO2 uptake of 3.72 mmol g−1 at 1.13 bar and 273 K.

Dibenzochrysene Enables Tightly Controlled Docking and Stabilizes Photoexcited States in Dual-Pore Covalent Organic Frameworks

2019 ◽  
Author(s):  
Torben Sick ◽  
Niklas Keller ◽  
Nicolai Bach ◽  
Andreas Koszalkowski ◽  
Julian Rotter ◽  
...  
Keyword(s):  
Molecular Docking ◽  
Photophysical Properties ◽  
Visible Spectrum ◽  
Large Family ◽  
Building Blocks ◽  
Band Gaps ◽  
Docking Site ◽  
Covalent Organic Frameworks ◽  
Connected Node ◽  
Optoelectronic Applications

Covalent organic frameworks (COFs), consisting of covalently connected organic building units, combine attractive features such as crystallinity, open porosity and widely tunable physical properties. For optoelectronic applications, the incorporation of heteroatoms into a 2D COF has the potential to yield desired photophysical properties such as lower band gaps, but can also cause lateral offsets of adjacent layers. Here, we introduce dibenzo[g,p]chrysene (DBC) as a novel building block for the synthesis of highly crystalline and porous 2D dual-pore COFs showing interesting properties for optoelectronic applications. The newly synthesized terephthalaldehyde (TA), biphenyl (Biph), and thienothiophene (TT) DBC-COFs combine conjugation in the a,b-plane with a tight packing of adjacent layers guided through the molecular DBC node serving a specific docking site for successive layers. The resulting DBC-COFs exhibit a hexagonal dual-pore kagome geometry, which is comparable to COFs containing another molecular docking site, namely 4,4′,4″,4‴-(ethylene-1,1,2,2-tetrayl)-tetraaniline (ETTA). In this context, the respective interlayer distances decrease from about 4.60 Å in ETTA-COFs to about 3.6 Å in DBC-COFs, leading to well-defined hexagonally faceted single crystals sized about 50-100 nm. The TT DBC-COFs feature broad light absorption covering large parts of the visible spectrum, while Biph DBC-COF shows extraordinary excited state lifetimes exceeding 10 ns. In combination with the large number of recently developed linear conjugated building blocks, the new DBC tetra-connected node is expected to enable the synthesis of a large family of strongly p-stacked, highly ordered 2D COFs with promising optoelectronic properties.

scholarly journals 22.F. Workshop: What makes for resilient health systems? Evidence from the State of Health in the EU country profiles

2020 ◽  
Vol 30 (Supplement_5) ◽  
Author(s):  
◽  
Keyword(s):  
Health System ◽  
Health Systems ◽  
Building Blocks ◽  
The State ◽  
Lessons Learned ◽  
Three Dimensions ◽  
Health System Strengthening ◽  
New Work ◽  
State Of Health ◽  
The Eu

Abstract The European Commission's State of Health in the EU (SoHEU) initiative aims to provide factual, comparative data and insights into health and health systems in EU countries. The resulting Country Health Profiles, published every two years (current editions: November 2019) are the joint work of the European Observatory on Health Systems and Policies and the OECD, in cooperation with the European Commission. They are designed to support the efforts of Member States in their evidence-based policy making and to contribute to health care systems' strengthening. In addition to short syntheses of population health status, determinants of health and the organisation of the health system, the Country Profiles provide an assessment of the health system, looking at its effectiveness, accessibility and resilience. The idea of resilient health systems has been gaining traction among policy makers. The framework developed for the Country Profiles template sets out three dimensions and associated policy strategies and indicators as building blocks for assessing resilience. The framework adopts a broader definition of resilience, covering the ability to respond to extreme shocks as well as measures to address more predictable and chronic health system strains, such as population ageing or multimorbidity. However, the current framework predates the onset of the novel coronavirus pandemic as well as new work on resilience being done by the SoHEU project partners. This workshop aims to present resilience-enhancing strategies and challenges to a wide audience and to explore how using the evidence from the Country Profiles can contribute to strengthening health systems and improving their performance. A brief introduction on the SoHEU initiative will be followed by the main presentation on the analytical framework on resilience used for the Country Profiles. Along with country examples, we will present the wider results of an audit of the most common health system resilience strategies and challenges emerging from the 30 Country Profiles in 2019. A roundtable discussion will follow, incorporating audience contributions online. The Panel will discuss the results on resilience actions from the 2019 Country Profiles evidence, including: Why is resilience important as a practical objective and how is it related to health system strengthening and performance? How can countries use their resilience-related findings to steer national reform efforts? In addition, panellists will outline how lessons learned from country responses to the Covid-19 pandemic and new work on resilience by the Observatory (resilience policy briefs), OECD (2020 Health at a Glance) and the EC (Expert Group on Health Systems Performance Assessment (HSPA) Report on Resilience) can feed in and improve the resilience framework that will be used in the 2021 Country Profiles. Key messages Knowing what makes health systems resilient can improve their performance and ability to meet the current and future needs of their populations. The State of Health in the EU country profiles generate EU-wide evidence on the common resilience challenges facing countries’ health systems and the strategies being employed to address them.

sp2 carbon-conjugated covalent organic frameworks: synthesis, properties, and applications

2021 ◽  
Vol 5 (7) ◽  
pp. 2931-2949
Author(s):  
Xinle Li
Keyword(s):  
Chemical Stability ◽  
Optoelectronic Properties ◽  
Covalent Organic Frameworks ◽  
High Crystallinity ◽  
Synthesis Properties

sp2 carbon-conjugated COFs (sp2c-COFs) featuring an unparalleled combination of sp2 carbon linkages, extended π-conjugation, high crystallinity, permanent porosity, unique optoelectronic properties, and extraordinary chemical stability, have garnered enormous attention recently.

Covalent Organic Frameworks for Electrochemical Sensors: Recent Research and Future Prospects

2021 ◽  
Vol 17 ◽  
Author(s):  
Linyu Wang ◽  
Shasha Hong ◽  
Yuxi Yang ◽  
Yonghai Song ◽  
Li Wang
Keyword(s):  
Specific Surface ◽  
Electrochemical Sensors ◽  
Gas Adsorption ◽  
Low Cost ◽  
High Sensitivity ◽  
Crystalline Polymer ◽  
Synthesis Methods ◽  
High Porosity ◽  
Covalent Organic Frameworks ◽  
Covalent Bonds

Background: In recent years, electrochemical sensors are widely preferred because of their high sensitivity, rapid response, low cost and easy miniaturization. Covalent organic frameworks (COFs), a porous crystalline polymer formed by organic units connected by covalent bonds, have been widely used in gas adsorption and separation, drug transportation, energy storage, photoelectric catalysis, electrochemistry and other aspects due to their large specific surface, excellent stability, high inherent porosity, good crystallinity as well as structural and functional controllability. The topological structure of COFs can be designed in advance, the structural units and linkage are diversified, and the structure is easy to be functionalized, which are all beneficial to their application in electrochemical sensors. Methods: The types, synthesis methods, properties of covalent organic frameworks and some examples of using covalent organic frameworks in electrochemical sensors are reviewed. Results: Due to their characteristics of a large specific surface, high porosity, orderly channel and periodically arranged π electron cloud, COFs are often used to immobilize metal nanoparticles, aptamers or other materials to achieve the purpose of building electrochemical sensors with high sensitivity and good stability. Since the structure of COFs can be predicted, different organic units can build COFs with different structures and properties. Therefore, organic units with certain functional groups can be selected to build COFs with certain properties and used directly for electrochemical sensors. Conclusion: COFs have a good application prospect in electrochemical sensors.

Smart covalent organic frameworks: dual channel sensors for acid and base

2021 ◽  
Author(s):  
Jia Xin Koh ◽  
Keyu Geng ◽  
Donglin Jiang
Keyword(s):  
Pore Wall ◽  
Covalent Organic Frameworks ◽  
Luminescent Sensors ◽  
Dual Channel ◽  
Acid And Base

The fully π-conjugated sp2 carbon covalent organic frameworks upon integration with carboxylic electrolyte sites on the pore wall develop highly luminescent sensors. The sensors feature dual channel responsiveness and enable...

scholarly journals Flexible monomer-based covalent organic frameworks: design, structure and functions

CrystEngComm ◽  
2017 ◽  
Vol 19 (33) ◽  
pp. 4868-4871 ◽  
Author(s):  
Lanfang Zou ◽  
Xinyu Yang ◽  
Shuai Yuan ◽  
Hong-Cai Zhou
Keyword(s):  
Gas Adsorption ◽  
Adsorption Properties ◽  
Covalent Organic Frameworks ◽  
Design Structure ◽  
Structure And Functions

A new flexible monomer-based COF has been designed and synthesized and its structure and gas adsorption properties have been carefully investigated.

scholarly journals Covalent organic framework based microspheres as an anode material for rechargeable sodium batteries

2018 ◽  
Vol 6 (34) ◽  
pp. 16655-16663 ◽  
Author(s):  
Bidhan Chandra Patra ◽  
Sabuj Kanti Das ◽  
Arnab Ghosh ◽  
Anish Raj K ◽  
Parikshit Moitra ◽  
...  
Keyword(s):  
Anode Material ◽  
Gas Adsorption ◽  
Optoelectronic Devices ◽  
Covalent Organic Frameworks ◽  
Covalent Organic Framework ◽  
Sodium Batteries ◽  
Organic Framework

Covalent organic frameworks (COFs) promise several benefits as materials in terms of gas adsorption, for use in optoelectronic devices, etc.

A design strategy for the construction of 2D heteropore covalent organic frameworks based on the combination of C2v and D3h symmetric building blocks

2018 ◽  
Vol 9 (3) ◽  
pp. 279-283 ◽  
Author(s):  
Cheng Qian ◽  
En-Cheng Liu ◽  
Qiao-Yan Qi ◽  
Kaijia Xu ◽  
Guo-Fang Jiang ◽  
...  
Keyword(s):  
Building Blocks ◽  
Design Strategy ◽  
Covalent Organic Frameworks

A strategy to construct heteropore covalent organic frameworks has been developed based on a desymmetrization design which takes advantage of the combination of C2v and D3h symmetries.

Sign in / Sign up

Export Citation Format

Share Document