Construction Of Several Heteropore Covalent Organic Frameworks And Study On Their Porperties

This thesis is focused on the design and construction of imine-linked heteropore covalent organic frameworks(COFs),and their properties for gas adsorption have also been investigated.In the first part,a new strategy to construct heteropore covalent organic frameworks(COFs)bearing different pore shape and size has been developed.In this strategy,heteropore SIOC-COF-5 and SIOC-COF-6 were fabricated through the condensation of a D2h symmetrical tetramine and a D2h symmetrical tetraldehyde.These heteropore COFs with eclipsed AA stacking possess two different kinds of micropores:one being quadrangle and the other being inequilateral hexagon.They exhibit good adsorption capacities for CO2 and H2,with CO2 uptake being as high as 19.8 wt%(273 K,1 bar)and H2 uptake reaching 1.66 wt%(77 K,1 bar)for SIOC-COF-5,and displaying CO2 uptake of 13.9 wt%(273 K,1 bar)and H2 uptakes of 1.79 wt%(77 K,1 bar)for SIOC-COF-6,respectively.It is a general strategy which could also be applicable to other building blocks with the same symmetry to construct heteropore COFs.In the second part,a new strategy has been developed to construct heteropore COFs with Kagome lattices.COF-BTA-DAB and COF-BTA-BZ were fabricated through the combination of D2h symmetrical tetraldehyde and C2 symmetrical diamine.To the best of our knowledge,this is the second build block that can produce COFs with Kagome structures.The structures of the dual-pore COFs have been confirmed by powder X-ray diffraction(PXRD)investigation,nitrogen adsorption-desorption study,and theoretical calculations.We also carried out CO2 adsorption experiments for the as-prepared COFs at 77 K and 1 bar.The experimental results indicated CO2 uptakes of 13.2 wt%for COF-BTA-DAB and 7.4 wt%for COF-BTA-BZ,respectively.These unique structures are not only instructive to researches in mathematics,physics and materials science,but also will enrich the family of heteropore COFs.