Squarephaneic Tetraanhydride: A Macrocyclic Building Block for Conjugated Porous Organic Materials

Abstract

Conjugated macrocycles provide an exciting playing field for the discovery of effects and properties that cannot usually be attained. In contrast to other organic molecules, they can sustain global aromatic or antiaromatic ring currents, which offers exciting opportunities for fundamental and applied research. Utilizing such ring currents occurring in paracyclophanetetraene (PCT), we have presented a molecular design concept that addresses the issues of degradation and unsatisfying long-term cycling performance of organic electrode materials by switching between local and global aromaticity upon redox reactions. However, for a broader use of PCT as a (sub)structure in organic electronic materials, a suitable reactive building block for the synthesis of such materials was missing. Considering the high reactivity and widespread use of aromatic carboxylic anhydrides in the synthesis of organic materials, we therefore aimed to develop a building block that features PCT as a substructure as well as carboxylic anhydride groups for a facile functionalisation. The molecule resulting from this design process, squarephaneic tetraanhydride (SqTA), will be presented in this talk. The building block can be obtained in a three-step synthesis and functionalised efficiently to give materials with highly interesting properties. Considering the short synthesis and the unique properties of SqTA and the materials obtained from its further conversion, we expect widespread use of SqTA in the synthesis of organic materials.