Preparation And Application Of Chiral TAPB-PDA Covalent Organic Frameworks

Covalent organic frameworks(COFs),a type of porous framework material,have attracted wide attention owing to their high specific surface area,high degree of crystallization,tunable pore sizes,and low density.Up to now,the main ways,bottom-up approach and post-synthesis strategy,have been developed for the preparation of chiral COFs.Therefore,the main work of this thesis focused on the preparation of a series of chiral COFs based on TAPB-PDA.The separation ability of these COFs was also studied.The results indicated that chiral COFs could be prepared using L-(or D-)tartaric acid as the catalyst.Moreover,the optical activity of these COFs mainly originated from the tartaric acid residue.However,chiral COFs were failed to be prepared using L-(or D-)lactic acid as the catalyst,using(R)-1-phenylethanol,1-(2-naphthyl)ethanol,(S)-β-citronellol,and(R)-2-methyl-1-butanol as chirality inducers,and using Fmoc-L-Phe for modification.Chiral COFs were also failed to be prepared by partially replacing of 1,3,5-tris(4-aminophenyl)benzene using(R)-1-phenylethylamine and(R)-1-(2-naphthyl)-ethylamine.Finally,the obtained chiral COFs were used as stationary phase of capillary gas chromatography column.Due to poor coating performance,the theoretical plate numbers of them were quite low.Up to now,a series of normal-alkanes and a series of normal-alcohols had been separated.In addition,the optical activity of single-handed twisted mesoporous silica nanoribbons was characterized using optical rotation spectroscopy.Left-and right-handed twisted silica nanoribbons exhibited identical optical rotation spectra and ultraviolet-visible spectra.This result was proposed to be caused by the heterogeneity of the samples.Carbonaceous nanofibers were prepared by the carbonization of the templates within the pore channels of silica nanoribbons.However,only carbonaceous particles were obtained,which were proposed to be formed by the accumulation of carbonaceous nanofibers.The length of 4,4’-biphenylene-bridged polybissilsesquioxane nanotubes was successfully controlled by tuning the ethanol/water volume ratio.Optically active carbon nanotubes were tried to be prepared using iron nanoparticles trapped in chiral mesopores.However,the obtained nanotubes were not optically active.