For product inquiries, please use our online system or send an email to .

chemistry partner
  • Home
  • Products
  • COFs Linkers
  • Halogen COFs Linkers
  • Halogen COFs Linkers


    Halogen COFs linkers are the monomers containing halogen atoms such as fluorine, chlorine, bromine and iodine for synthesis of COFs. And they can also be known as halogenated COFs linkers or halogenated COFs monomers. Among them, the organic linkers containing fluorine, bromine and chlorine are often used to construct COFs. Because they have high reactivity and can perform different reactions with other functional groups (e.g. phenol, phenyl, alkyne, imino, etc.) of monomer which commonly used in COF, such as nucleophilic substitution reaction, Friedel−Crafts reaction, Schiff base reaction, coupling reaction, etc. Through these reactions, COFs with different linkages can be synthesized. Therefore, halogen-containing compound can also be regarded as a kind of important linker in COFs. In addition, halogen atoms as typical electron-absorbing groups exhibit good electronegativity, which can regulate the localized electron cloud density and delocalization of conjugated building blocks and promote the separation transfer of electrons. Thus, halogen hybrid linkers whose structures also contain other functional groups such as amines and boric acid groups are frequently used to bring unexpected photoelectric properties to COFs materials. In this process, amines and boric acid functional groups are reacted to form the COFs structure, while halogen atoms are not directly involved in the synthesis reaction of COFs.

    Fig. 1. Chemical structure of two common halogen linkers.Fig. 1. Chemical structure of two common halogen linkers.


    Halogen-containing linkers can be used to construct different types of COFs. Here, some of typical synthesis application of halogen COFs linkers are briefly introduced.

    • Synthesis of dioxin-linked COFs: The fluorine-containing monomers can perform nucleophilic aromatic substitution (SNAr) reaction with phenol containing monomers to synthesize dioxin-linked COFs. Fluorine atoms on the monomers are electron-withdrawing moieties, which tend to increase the extent of nucleophilic attack by the hydroxyl group, resulting in a SNAr reaction. In 2018, two 2D COFs, COF-316 and COF-318, were synthesized by this strategy in which the triangular monomer 2,3,6,7,10,11-hexahydroxytriphenylene (HHTP) combines with either the linear tetrafluorophthalonitrile (TFPN) or 2,3,5,6-tetrafluoro-4-pyridinecarbonitrile (TFPC), respectively [1]. In addition, a series of dioxin-linked metallophthalocyanine COFs, MPc-TFPN COFs (M = Ni, Co, and Zn), were also prepared by this strategy using tetrafluorophthalonitrile (TFPN) and 2,3,9,10,16,17,23,24-octahydroxyphthalo -cyaninato metal (MPc-8OH; M = Ni, Co, and Zn). Dioxin-linked COFs are a family of stable materials due to the strong nature of their covalent bonds [2].

    Fig. 2. Schematic of the synthesis and structure of MPc-TFPN COFs through the condensation of MPc-8OH and TFPN.Fig. 2. Schematic of the synthesis and structure of MPc-TFPN COFs through the condensation of MPc-8OH and TFPN.

    • Synthesis of C–C coupling based COF: C–C coupling reactions between tetrabromopolyaromatic monomers can be used to prepare the 2D COF. One typical example of this was reported by Liu et al. in 2017, where a highly ordered 2D-CAP COF from the exceptionally rigid 2,7,13,18-tetrabromodibenzo[a,c]dibenzo [5,6:7,8] quinoxalino[2,3-i]phenazine (2-TBQP) building block was successfully engineered. The 2D-CAP was formed via metal-surface-mediated polymerization at an elevated temperature of ~250 ℃, where the debromination of 2-TBQP and aryl–aryl coupling reaction occurred. The obtained 2D-CAP has a highly uniform pore size of ∼0.6 nm and well-defined channels, which can be exploited for energy storage in sodium ion batteries (NIBs) [3]. A similar example was reported the next year, in 2018, CAP-1 and CAP-2 were synthesized.

    Fig. 3. Synthesis of 2D-CAP by the metal-surface-mediated polymerization of 2-TBQP.Fig. 3. Synthesis of 2D-CAP by the metal-surface-mediated polymerization of 2-TBQP.

    • Synthesis of triazine-linked COFs (CTFS): The synthesis methods of CTFs are classified into two categories based on the way the triazine unit is incorporated, i.e., synthesis of CTFs by constructing triazine units and synthesis of CTFs by directly introducing triazine unit containing monomers. In the latter strategy, halogen-containing linkers are widely used and various reactions have been developed based on them. These reactions include nucleophilic substitution between cyanuric chloride and nucleophilic reagents, a Friedel-Crafts alkylation reaction between cyanuric chloride and aromatic rings, Sonogashira cross coupling between bromine and alkyne groups, and a Ni-catalyzed Yamamoto coupling reaction of aromatic bromine [4].

    Fig. 4. Typical synthesis of CTFs through the direct introduction of triazine units based on halogen-containing linkers.Fig. 4. Typical synthesis of CTFs through the direct introduction of triazine units based on halogen-containing linkers.

    Alfa Chemistry offers a series of halogenated monomers for synthesis of various types of COFs such as dioxin-linked COFs, C–C coupling based COF, triazine-linked COFs (CTFS), etc. In addition, these halogen-containing monomers can also be used as intermediates for the synthesis of COFs linkers. You can click on our product list for a detailed view. At the same time, we also offer product customization according to customer's detailed requirements. If you are interested in our products or have any questions or needs, please feel free to contact us. We will be happy to provide you with support and services.


    1. Zhang B., et al. Crystalline dioxin-linked covalent organic frameworks from irreversible reactions[J]. Journal of the American Chemical Society, 2018, 140(40): 12715-12719.
    2. Lu M., et al. Stable Dioxin‐Linked Metallophthalocyanine Covalent Organic Frameworks (COFs) as Photo‐Coupled Electrocatalysts for CO2 Reduction[J]. Angewandte Chemie, 2021, 133(9): 4914-4921.
    3. Liu W., et al. A two-dimensional conjugated aromatic polymer via C–C coupling reaction[J]. Nature chemistry, 2017, 9(6): 563-570.
    4. Liao L., et al. Advances in the Synthesis of Covalent Triazine Frameworks[J]. ACS omega, 2023, 8(5): 4527-4542.

    Quick Inquiry

    Verification code


    Interested in our Services & Products?
    Need detailed information?

    Contact us