Design,Construction,and Modelization Of Functional-Oriented Covalent Organic Framework Materials

Covalent organic frameworks（COFs）are rapidly being developed as a new crystalline porous material.Compared with traditional materials,COFs have attracted more attention because of their excellent properties,such as ultra-high porosity,high specific surface area,regular pore structure,ultra-low density,and high stability.Thus,COFs exhibit considerable potential for application in heterogeneous catalysis,gas separation and transformation,molecular recognition,and biomedicine,among others.Although considerable efforts have been invested to design the physical or chemical properties of COFs materials,the importance of processability for their applications should be accounted for.Based on the design and construction of a functional and stable covalent organic framework,four functional COF-based device-type composites were successfully fabricated using a covalent crosslinking or self-assembly strategy.Their CO₂adsorption selectivity,catalytic conversion,and antibacterial and antiviral properties are investigated in this thesis.This paper presents a new concept for the synthesis and design of functional COFs matrix composites and broadens the application prospects of COFs matrix composites in biomedicine and environmental energy.Ⅰ.A novel COF material（COF-IL）with a modified alkyl imidazolium ionic liquid was successfully synthesized,which has a high adsorption selectivity for CO₂under environmental conditions,via a solvothermal method.As a highly active heterogeneous catalyst,COF-ILs also promote the cycloaddition of CO₂.For the gram-level treatment of CO₂,a novel chitosan composite aerogel（COF-IL@chitosan）was prepared via the covalent cross-linking of COF-IL and chitosan-SH through the click reaction.The crystalline structure,highly selective CO₂adsorption,and catalytic conversion features of COF-IL were well maintained in the composite aerogel.Meanwhile,the generated covalently coupled COF-chitosan composite material,COF-IL@chitosan,was robust,uniform,and processable even with a remarkably high COF loading（up to 80 wt%）.More importantly,the processable COF-IL@chitosan aerogel was readily shaped into a simplified fixed-bed reactor model via a facile templated freeze-drying procedure,and a scalable recyclable CO₂cycloaddition reaction was realized.Ⅱ.A porphyrin and imidazolium-ionic liquid（IL）-decorated quinoline-linked covalent organic framework（COF-P1-1）was successfully constructed via a three-component one-pot Povarov reaction.After the post-synthetic metallization of COF-P1-1 with Co（II）ions,metallized COF-PI-2 was generated.The stable COF-PI-2 exhibits not only a high CO₂adsorption selectivity but also a good visible-light-induced photothermal conversion ability（ΔT=26°C）.The high activity of COF-PI-2 for the CO₂cycloaddition reaction was verified owing to the coexistence of metal porphyrins and imidazole ionic liquids.Notably,the thermal energy required for the reactions was derived from the photothermal conversion of the Co（II）-porphyrin COF upon visible light or natural light irradiation.In addition,the COF-PI-2@chitosan aerogel-based fixed model reactor was prepared by a simple freeze-drying method,which can easily realize CO₂gram-level process transformation driven by clean energy.This paper presents a new,environment-friendly,and energy-saving method for COF-based greenhouse gas treatment.Ⅲ.We obtained a homogeneous and self-supporting porphyrin-based covalent organic framework membrane material via in situ interfacial polymerization.After encapsulation with ibuprofen（IBU）,an IBU@Dha Tph membrane material was successfully prepared.Because of the advantages of the synergistic photoinduced production of singlet oxygen（¹O₂）and the controllable release of IBU,in vitro experiments confirmed the hypothesis that the IBU@Dha Tph membrane exhibits high antibacterial and anti-inflammatory effects.In addition,an IBU@Dha Tph-membrane-based biocompatible“band-aid”type dressing was fabricated,and its excellent anti-infection and tissue remodeling activities were fully evidenced by in vivo chronic wound healing experiments.This study is expected to promote the preparation of significant COF-based multifunctional skin injury biomaterials in clinical medicine.Ⅳ.We successfully prepared quinolin-4-carboxylic acid-linked hydroxyl-rich porphyrin-based COFs using a three-component one-pot in situ Doebner reaction,and the nanoscale COFs composite Ag@Dha Tph-COOH was constructed through sequential solution impregnation and Na BH₄.After mixing the hydroxyl-enriched COF NPs with isocyanate-terminated polyurethane oligomers,the covalently cross-linked COF dispersion was sprayed onto the outer layer of the non-woven PET fabric surface to yield a face mask with the deposited Ag@Dha Tph-COOH NPs.Owing to the triple mode of chemotherapy/PDT/PTT under natural sunlight irradiation,the prepared mask exhibits a high killing efficiency for bacteria and viruses that can be transmitted in air and is reusable.