Development of Rigid Aromatic Building Blocks for the Application in Material Sciences

Climate change has received an increasing attention in the recent years; however, in the scientific community, intensive research has already been conducted for several years on the transition from fossil fuels to more environmentally friendly, renewable energies. One of the main interests is a more efficient storage method for gaseous energy carriers such as hydrogen or methane. Porous materials with an outstanding specific surface area, high stability, and a low density, are highly interesting candidates for this task. COFs represent such a class of materials and are assembled of rigid, symmetric, highly functionalized building blocks. The nitroxide exchange reaction between multifunctional alkoxyamines and nitroxides represents a new approach to generate these materials. Therefore, a robust procedure for the synthesis of multifunctional alkoxyamines with different geometries was successfully established in this thesis. As counterparts, several nitroxides were synthesized, resulting in more than 50 possible combinations for the generation of porous materials. In addition to COFs, non-crystalline frameworks such as POPs can also serve as storage platforms for gaseous energy carriers. Therefore, in a second project, multifunctional azides were prepared and subsequently converted into strongly expanded, porous polymers. The specific surface area of these materials could be controlled with the reaction temperature, while the appearance changed with the geometry of the azide building blocks.