Construction of new covalent organic frameworks with benzimidazole moiety as Fe3+ selective fluorescence chemosensors

Nitrogen-rich covalent organic frameworks: a promising class of sensory materials

“…COF-BI-1 and COF-BI-2, conventionally synthesized from pyromellitic dianhydride (PMDA)/ perlin-tetracarboxylic anhydride (PTCA), 5aminoisophthalic acid and 3,3'-diaminobenzidine, to show a significant fluorescent quenching with the incremental addition of a Fe 3+ ion solution to COF-BI-1 in THF and COF-BI-2 in DMF up to the limit of 1.3 M. 254 An evident fluorescence "turn-on" mechanism was reported by Qiu and co-workers where the PL intensity of the water-stable covalent organic nanosheets Bpy-NSs, was enhanced with the incremental addition of Al 3+ ions out of several monovalent (Li + , Na + , K + , Ag + ), divalent (Zn 2+ , Mn 2+ , Cd 2+ , Cu 2+ , Mn 2+ , Ni 2+ , Co 2+ , Pb 2+ , Ba 2+ , Ca 2+ ) and other trivalent (Cr 3+ , Fe 3+ ) metal ions in aqueous media. 255 The photoluminescence intensity of the N-rich Bpy-NSs nanosheets were limited due to extensive energy dissipation by bipyridine (Bpy) moieties leading to photoinduced electron transfer to phloroglucinol centres.…”

Novel nanoscale vanillin based covalent triazine framework as a novel carrier for sustained release of imatinib

“…Covalent porous crystalline polymers named as covalent organic frameworks (COFs) represented as a new material consist of light elements that crystallize into polymeric well‐organized structures via robust covalent bonds 1 . Tenability of structure and pore size, diverse functionality, high crystallinity, great surface area and distinct molecular structure makes the COF as a good candida for applications in energy storage, gas adsorption and separation, chemical sensing, optoelectronics, capacitors, catalysis, energy conversion and batteries 2–5 . The synthesis of nanoscale COF opened the way for the use of these materials in therapeutic applications 6 .…”

“…batteries. [2][3][4][5] The synthesis of nanoscale COF opened the way for the use of these materials in therapeutic applications. 6 In fact, high loading capacity, reasonable release behavior, high stability and low structurally toxicity which are respectively related to high porosity, and multifunctionality of organic building blocks, durable covalent bond linkage and lack of metal in COFs, has proved distinct advantages of these material for nanomedical applications.…”

Post-synthetic modifications of covalent organic frameworks (COFs) for diverse applications

“…Due to the topology and linkage diversity as well as building monomers with different sizes, reactive groups, chiral centers, and docking sites, various COFs have been constructed. 2 Due to their specific attributes, these compounds have found usage in catalysis, 3,4 sensors, [5][6][7] separation, 8,9 adsorption, [10][11][12][13] energy storage, [14][15][16] drug delivery, [17][18][19][20] and electronic devices. [21][22][23] Functional groups of COFs play a key role in these applications.…”