Synthesis Of Porphyrin Based Chiral Covalent Organic Frameworks And Their Application In Enantioseparation

Covalent organic frameworks(COFs)represent an emerging class of porous crystalline polymers composed of light-weight elements(C,O,N,B,Si)and constructed via strong covalent bonds.Synthesis of COFs relies on reversible polymerization of thermodynamic control.COFs possess lots of unique properties such as low densities,high thermal stabilities,large surface areas,permanent porosity,regular structure,which make COFs potential in various fields.However,the applications of COFs in chiral separation are underexplored due to the limited chiral COFs available.In this paper,a series of chiral COFs were prepared by post-synthetic modification,and their chiral separation properties were studied.We chose porphyrin based[OH]-H2P COFs with larger planar ? electron systems and more modifiable sites as basic backbones.The hydroxyl groups in the pore channels can be used for functionalization.Chiral COFs were obtained by channel modification of four[OH]-H2P COFs with(S)-O-acetylmandehc acid chloride,R-(-)-2-phenylpropionyl chloride or(+)-diacetyl-L-tartaric anhydride.Chiral COFs was obtained by esterification reaction with acyl chloride in the channels of COFs,and chiral anhydride was adsorbed in the channels of COFs for the case of(+)-diacetyl-L-tartaric anhydride.Chiral COFs were used as gas chromatography stationary phase to prepare gas chromatography column.[S-MA]100%-H2P COF-bound capillary column and[R-HTA]100%-H2P COF-bound capillary column have certain separation and recognition ability for 1-phenylethanol,dichlorobenzene,dibromobenzene and nitrotoluene,and baseline separation for n-alkanes and n-alcohols can be achieved.[R-HTA]75%-H2P COF-bound capillary column has certain separation effect for dichlorobenzene,and baseline separation can be achieved for benzene homologues,n-alkanes and n-alcohols.The(+)-DIA-L-TA-[OH]25%-H2P COF-bound capillary column has certain separation and recognition effect for five low boiling point alkanes.