Synthesis And Applications Of Functionalized 3D COF

Covalent organic frameworks?COF?,as an exciting new type of crystallineporous polymers,are made from lightelements,typically H,B,C,N,and O,which crystallize into periodic networks by the formation of reversible covalent bonds.Owing to their high porosity,large specific surfacearea,and good thermal/chemical stability,the COF materials have attracted much attention for considerable potential in gas storage and separation,catalysis,organic electronics,and many others.Over the past decade,most of the reported work on COF,however,were focused on 2D COF with layered eclipsed structures.Especially functionalized 3D COF,have recently attracted extensive interest due to their unique porous features and excellent performances.Owing to the design and synthesis of 3D COF are more difficult than those of 2D COF.Firstly,the crystallization problems are more significant for 3D COF and the synthesis conditions are more rigid and precise for 3D frameworks,especially for those monomers with functional moieties.Besides,the phenomenon of interpenetration is universal in 3D COF'structures and the chemical stabilities of 3D COF are generally weak,resulting in the limited applications of 3D COF.Therefore,designing 3D functionalized COF is very important for expanding their structural types amd applications.Based on the questions mentioned above,We used different strategies to prepare a series of functionalized 3D COF with three different topos?dia,ctn,pts?.And their performances in one-pot cascade catalysis,the seperation of CO₂ and electrochemistry were discussed in this thesis.This thesis includes the following three parts:?1?Covalent organic frameworks?COF?are anemerging class of porous crystalline polymers with broad potential applications.So far,the availability of 3D COF is limited and more importantly only one type of covalent bond has been successful used for 3D COF materials.Here,we report a new synthetic strategy based on dual linkages that leads to 3D COF.The obtained 3D COF show high specific surface areas and large gas uptake capacities,which makes them the top COF material for gasuptake.Furthermore,we demonstrate that the new 3D COF comprise both acidic and basic sites,and act as excellent bifunctional catalysts for one-pot cascade reactions.The new synthetic strategy provides not only a general and versatile approach to synthesize 3D COF with sophisticated structures but also expands the potential applications of this promising classof porous materials.?2?Covalent organic frameworks?COF?are an emerging class of porous crystalline polymers with widerange of potential applications.However,the availability of 3D COF is still limited,and their synthesis is confined to the high-temperature solvothermal method.Here,we report for the first time a general andsimple strategy to produce a series of 3D ionic liquid?IL?-containing COF?3D-IL-COF?by using IL as a greensolvent.The syntheses are carried out at ambient temperature and pressure accompanied by a high reaction speed?e.g.,only three mins for 3D-IL-COF-1?,and the ILcan be reused without activity loss.Furthermore,the 3DIL-COFs show impressive performance in the separation of CO₂/N₂ and CO₂/CH₄.This research thus presents a potential pathway to green large-scale industrial production of COF?3?The functionalization of three-dimensional covalent organic frameworks?COF?is essential to broaden their applications.However,the introduction oforganic groups with electroactive abilities into 3D COF is still very limited.Herein we report the first case of tetrathiafulvalene-based 3D COF?3D-TTF-COF?withnon-or 2-fold interpenetrated pts topology and tunableelectrochemical activity.The obtained COF show highcrystallinity,permanent porosity,and large specific surfacearea(up to 3000m²g^-1).Furthermore,these TTF-based COF are redox active to form organic salts that exhibit tunable electric conductivity(as high as 1.4×10^-22 S cm^-1at 120°C)by iodine doping.These results open a way toward designing electroactive 3D COF materials and promote their applications in molecular electronics andenergy storage.