Construction Of Spiro-Based Covalent Organic Frameworks

Covalent organic frameworks(COFs)are a new class of crystalline porous materials,which are constructed with organic building units through dynamic covalent bonds.Due to their low density,large surface area,and controllable functions,COFs show good potentials in the fields of gas storage,photoelectricity,catalysis,and sensing.Possessing the rigid structure,spiro compounds have many applications in catalysis and photoelectricity.Accordingly,in this thesis,we focus on the construction of spiro-based COFs.The main work was summarized as follows:By using the spiro compounds as the precursors,five novel 3D COFs(LZU-160,LZU-161,LZU-162,LZU-163,LZU-164)were constructed through the imine-bonds.The effects of solvent,acidity,temperature,and reaction time were investigated.Meanwhile,the properties of these materials were characterized and indicated that these materials are crystalline and display non-porous.To incorporate the functionalities and increase the stability of these spiro-based materials,the hydroxyl groups in the ortho position of the aldehydes were synthesized as the precursors.And another five novel spiro-based 3D COFs(LZU-165,LZU-166,LZU-167,LZU-168,LZU-169)were synthesized and characterized.The results indicate that these are nonporous materials.