Covalent Organic Frameworks (COFs) and Related Porous Organic Materials

A special issue of Polymers (ISSN 2073-4360). This special issue belongs to the section "Polymer Chemistry".

Deadline for manuscript submissions: closed (31 May 2019) | Viewed by 26656

Special Issue Editor

Department of Chemistry, Center for Ordered Materials, Organometallics and Catalysis (COMOC), Faculty of Sciences, Ghent University, Krijgslaan 281 (S3), 9000 Ghent, Belgium
Interests: metal–organic frameworks; covalent organic frameworks; (electro)catalysis; adsorption
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Special Issue Information

Dear Colleagues,

In 2005, a prominent discovery was made by Omar Yaghi, who showed that it is possible to assemble organic building units into crystalline porous materials—since then referred to as covalent organic frameworks (COFs). Linking together organic monomers into polymers is obviously widely known, but the creation of well-defined crystalline nanoporous frameworks based merely on organic (metal-free) monomers was a new concept. COFs have similar characteristics in comparison to the well-known metal organic frameworks (MOFs). In general, COFs possess very low densities and high surface areas, and have an inherent porosity and pore aperture which can be tuned by using bigger/smaller building units. Nevertheless, in contrast to MOFs, COFs possess a higher thermal and chemical stability allowing pre- or post-synthetic modifications for specific applications without introducing a significant change in the porosity or loss in crystallinity.

This Special Issue aims to report the recent progress in covalent organic frameworks and related materials ranging from new synthesis routes to new structures and properties, which can be applied in (but not limited to) catalysis, adsorption, luminescence, and sensing applications.

Dr. Karen Leus
Guest Editor

Keywords

  • covalent organic frameworks
  • catalysis
  • adsorption
  • luminescence
  • sensing

Published Papers (5 papers)

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Research

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12 pages, 2701 KiB  
Article
Ionic Porous Organic Polymers Based on Functionalized Tetraarylborates
by Patryk Tomaszewski, Marcin Wiszniewski, Krzysztof Gontarczyk, Piotr Wieciński, Krzysztof Durka and Sergiusz Luliński
Polymers 2019, 11(6), 1070; https://doi.org/10.3390/polym11061070 - 21 Jun 2019
Cited by 3 | Viewed by 4080
Abstract
Lithium tetrakis(4-boronatoaryl)borates were subjected to polycondensation reactions with selected polyhydroxyl monomers such as 2,3,6,7,10,11-hexahydroxytriphenylene (HHTP) and 2,3,6,7-tetrahydroxy-9,10-dimethylanthracene (THDMA). Obtained boronate-type ionic porous polymers TAB1–4 were characterized by PXRD, 6Li and 11B magic-angle spinning nuclear magnetic resonance (MAS NMR), FT-IR, SEM, and [...] Read more.
Lithium tetrakis(4-boronatoaryl)borates were subjected to polycondensation reactions with selected polyhydroxyl monomers such as 2,3,6,7,10,11-hexahydroxytriphenylene (HHTP) and 2,3,6,7-tetrahydroxy-9,10-dimethylanthracene (THDMA). Obtained boronate-type ionic porous polymers TAB1–4 were characterized by PXRD, 6Li and 11B magic-angle spinning nuclear magnetic resonance (MAS NMR), FT-IR, SEM, and TGA. They exhibit relatively good sorption of H2 (up to 75 cm3/g STP), whereas N2 uptake at 77 K for lower pressure range is relatively poor (up to 50 cm3/g STP below P/P0 = 0.8). In addition, the effect of elongation of aryl arms in the tetraarylborate core on the materials’ properties was studied. Thus, it was found that replacement of the 4-boronatophenyl with 4-boronatobiphenylyl group has a negative impact on the sorption characteristics. Full article
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10 pages, 2215 KiB  
Article
Room-Temperature Fabrication of a Nickel-Functionalized Copper Metal–Organic Framework (Ni@Cu-MOF) as a New Pseudocapacitive Material for Asymmetric Supercapacitors
by Yi Wang, Shengqiang Nie, Yuan Liu, Wei Yan, Shaomin Lin, Gang Cheng, Huan Yang and Jun Luo
Polymers 2019, 11(5), 821; https://doi.org/10.3390/polym11050821 - 07 May 2019
Cited by 38 | Viewed by 6095
Abstract
A nickel-functionalized copper metal–organic framework (Ni@Cu-MOF) was prepared by a facile volatilization method and a post-modification synthesis method at room temperature. The obtained Ni@Cu-MOF electrode delivered a high capacitance of 526 F/g at 1 A/g and had a long-term cycling stability (80% retention [...] Read more.
A nickel-functionalized copper metal–organic framework (Ni@Cu-MOF) was prepared by a facile volatilization method and a post-modification synthesis method at room temperature. The obtained Ni@Cu-MOF electrode delivered a high capacitance of 526 F/g at 1 A/g and had a long-term cycling stability (80% retention after 1200 cycles at 1 A/g) in a 6 M KOH aqueous solution. Furthermore, an asymmetric supercapacitor device was assembled from this Ni@Cu-MOF and activated carbon electrodes. The fabricated supercapacitor delivered a high capacitance of 48.7 F/g at 1 A/g and a high energy density of 17.3 Wh/kg at a power density of 798.5 kW/kg. This study indicates that the Ni@Cu-MOF has great potential for supercapacitor applications. Full article
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11 pages, 1410 KiB  
Article
Adamantane-Based Micro- and Ultra-Microporous Frameworks for Efficient Small Gas and Toxic Organic Vapor Adsorption
by Wenzhao Jiang, Hangbo Yue, Peter S. Shuttleworth, Pengbo Xie, Shanji Li and Jianwei Guo
Polymers 2019, 11(3), 486; https://doi.org/10.3390/polym11030486 - 13 Mar 2019
Cited by 8 | Viewed by 2963
Abstract
Microporous organic polymers and related porous materials have been applied in a wide range of practical applications such as adsorption, catalysis, adsorption, and sensing fields. However, some limitations, like wide pore size distribution, may limit their further applications, especially for adsorption. Here, micro- [...] Read more.
Microporous organic polymers and related porous materials have been applied in a wide range of practical applications such as adsorption, catalysis, adsorption, and sensing fields. However, some limitations, like wide pore size distribution, may limit their further applications, especially for adsorption. Here, micro- and ultra-microporous frameworks (HBPBA-D and TBBPA-D) were designed and synthesized via Sonogashira–Hagihara coupling of six/eight-arm bromophenyl adamantane-based “knots” and alkynes-type “rod” monomers. The BET surface area and pore size distribution of these frameworks were in the region of 395–488 m2 g−1, 0.9–1.1 and 0.42 nm, respectively. The as-made prepared frameworks also showed good chemical ability and high thermal stability up to 350 °C, and at 800 °C only 30% mass loss was observed. Their adsorption capacities for small gas molecules such as CO2 and CH4 was 8.9–9.0 wt % and 1.43–1.63 wt % at 273 K/1 bar, and for the toxic organic vapors n-hexane and benzene, 104–172 mg g−1 and 144–272 mg g−1 at 298 K/0.8 bar, respectively. These are comparable to many porous polymers with higher BET specific surface areas or after functionalization. These properties make the resulting frameworks efficient absorbent alternatives for small gas or toxic vapor capture, especially in harsh environments. Full article
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14 pages, 5092 KiB  
Article
Enzymes@ZIF-8 Nanocomposites with Protection Nanocoating: Stability and Acid-Resistant Evaluation
by Yuxiao Feng, Le Zhong, Muhammad Bilal, Zhilei Tan, Ying Hou, Shiru Jia and Jiandong Cui
Polymers 2019, 11(1), 27; https://doi.org/10.3390/polym11010027 - 25 Dec 2018
Cited by 59 | Viewed by 5931
Abstract
Zeolitic imidazole framework-8 (ZIF-8) with tunable pore sizes and high surface areas have recently emerged as a promising support for immobilizing enzymes. However, the instability in the aqueous acidic environment and difficulty of recovery has limited their practical applications in some cases. In [...] Read more.
Zeolitic imidazole framework-8 (ZIF-8) with tunable pore sizes and high surface areas have recently emerged as a promising support for immobilizing enzymes. However, the instability in the aqueous acidic environment and difficulty of recovery has limited their practical applications in some cases. In this study, catalase/ZIF-8 composites with a protective nanocoating were prepared by the controlled self-assembly of silanes or coordination complexes (tannic acid (TA) and Fe3+). The properties of the catalase (CAT)/ZIF-8 composites with a protective nanocoating were also determined. The recovered activity of CAT/ZIF-8 and CAT/ZIF-8 with protective nanocoating was 70% and 65%, respectively. Compared with the conventional CAT/ZIF-8 composites, CAT/ZIF-8 with protective nanocoating exhibited excellent acid resistance. For example, after treatment for 60 min in phosphate buffer solution (pH 3.0), CAT/ZIF-8 composites only maintained 20% of their initial activity (about 12 U/mg). However, CAT/ZIF-8 with a protective nanocoating could still retain about 50% of its initial activity (about 10 U/mg). Meanwhile, the thermostability and storage stability of the CAT/ZIF-8 composites was enhanced significantly due to the presence of nanocoating compared with conventional CAT/ZIF-8. More importantly, the CAT/ZIF-8 with a protective nanocoating retained 40% of its initial activity after 7 cycles, whereas CAT/ZIF-8 only retained 8% of the initial activity. The approach in this study could be an efficient strategy to prepare enzyme/ZIF-8 composites with both high acid resistance and excellent recyclability. Full article
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Review

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24 pages, 12039 KiB  
Review
Development of Covalent Triazine Frameworks as Heterogeneous Catalytic Supports
by Norini Tahir, Chidharth Krishnaraj, Karen Leus and Pascal Van Der Voort
Polymers 2019, 11(8), 1326; https://doi.org/10.3390/polym11081326 - 09 Aug 2019
Cited by 39 | Viewed by 6786
Abstract
Covalent triazine frameworks (CTFs) are established as an emerging class of porous organic polymers with remarkable features such as large surface area and permanent porosity, high thermal and chemical stability, and convenient functionalization that promotes great potential in heterogeneous catalysis. In this article, [...] Read more.
Covalent triazine frameworks (CTFs) are established as an emerging class of porous organic polymers with remarkable features such as large surface area and permanent porosity, high thermal and chemical stability, and convenient functionalization that promotes great potential in heterogeneous catalysis. In this article, we systematically present the structural design of CTFs as a versatile scaffold to develop heterogeneous catalysts for a variety of chemical reactions. We mainly focus on the functionalization of CTFs, including their use for incorporating and stabilization of nanoparticles and immobilization of molecular complexes onto the frameworks. Full article
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