Synthesis And Properties Of Sp~2 C-COFs Containing Bistriazine Units

Covalent organic frameworks（COFs）are a novel class of porous crystalline materials with regular two-dimensional（2D）or three-dimensional（3D）network structures formed by covalently linking organic building blocks.Due to their ideal crystallinity,low density,superior specific surface area,desirable pore size and designable functionalities,COFs have been widely used in chiral catalysis,electrochemistry,drug loading and delivery,photocatalysis,energy storage,and other fields.In this paper,ten new 2D sp~2 c-COFs were synthesized and characterized by a series of characterization methods.These ten 2D sp~2 c-COFs were constructed by Knoevenagel condensation reaction of bistriazine containing active methyl groups and linear dialdehydes.The properties of these materials were studied in the meantime.The main work of this paper is as following:In chapter 1,the classification of common COFs and their synthesis methods are described,and the basis and significance of this paper are clarified.In chapter 2,using 2,4,6-trimethyl-1,3,5-triazine（TMT）as raw material and rigid benzene as linear linker,a nitrogen rich symmetrical planar monomer 1,4-bis（4,6-dimethyl-1,3,5-triazine-2-yl）benzene（TMTA）with excellent conjugate structure and multiple redox active sites was designed and synthesized.Ten novel 2D sp~2 c-COFs were successfully constructed by Knoevenagel condensation reaction of the monomer and a variety of linear dialdehydes.The obtained COFs have widerπ-delocalization structure,higher crystallinity,larger specific surface area and more ordered pore structure.In chapter 3,a series of performance studies were carried out on the above 2D sp~2 c-COFs.The results showed that the supercapacitors（MSCs）based on them could show good electrochemical performance and cycle stability.Meanwhile,most COFs have acid-sensitive fluorescence activity.In addition,under the conditions of low loading and short reaction time,some COFs are suitable for photocatalytic hydrogen production from water splitting under visible light irradiation.In chapter 4,this paper is general overviewed and the future adhibition and development of COFs materials are predicted.