Functionalization of covalent organic frameworks [thesis]

Mirjam Dogru
Covalent Organic Frameworks (COFs) are a novel class of highly stable, purely organic crystalline frameworks made of molecular building blocks. For example, the condensation of boronic acids with appropriate polyols in principle allows the design of precisely controllable structures since their chemical and physical properties can be easily tuned through the selection of the building blocks. The young research field of COFs has attracted scientists due to their extraordinary and versatile
more » ... ties, however, strategies to control the topology and the properties of the backbone as well as the inner surface are still not well established. With support of Prof. Knochel and his group, who contributed numerous new organic COF linkers, this thesis aims to extend the functionalization strategies for the design of Covalent Organic Frameworks. Investigation of the structural modification and the associated change in physical and chemical properties should lead to progress regarding the applicability of these materials. Employing the concept of reticular chemistry in combination with High Throughput Synthesis Techniques, the formation of a very large Covalent Organic Framework BTP-COF with 4 nm open pores was successfully carried out. The solvothermal co-condensation of 1,3,5-benzenetris(4-phenylboronic acid) (BTPA) and 2,3,6,7-tetrahydroxy-9,10-dimethyl-anthracene (THDMA) was carried out using microwave irradiation instead of conventional synthesis in an oven, thus synthesis time of BTP-COF was reduced from initially 72 h to 5 min. Extending the open pore diameter of a crystalline material to 4 nm, in combination with the resulting high accessible surface area of 2000 m2/g offers great potential to exploit organic reactions in the pores and enables the incorporation of large functional guests, such as polymers or dyes. Bearing these results in mind the scope of functionalization possibilities was expanded from the geometric extension to the chemical modification of the inner surface of COFs. Decorating the organic buildi [...]
doi:10.5282/edoc.14096 fatcat:sxozvptjanhlhd3eixytznhloe