Synthesis of New [2.2]Paracyclophane Derivatives for Application in Material Sciences

Since the first discovery of [2.2]paracyclophane 70 years ago, this molecule has sparked tremendous interest in the scientific community. The two coplanar phenyl rings are fixed in close proximity by two short ethyl bridges in para-position resulting in a ``bent and battered'' molecular skeleton which is unknown in conventional aromatic chemistry. The key features of this molecule are the unique electronic situation including transannular communication, the presence of planar chirality upon substitution, and the considerable spherical bulk. Despite these unique features, the unusual conformation and therefore electronic situation influences the chemistry of this molecule dramatically, making synthetic derivatizations a challenging endeavor. This work focuses on establishing synthetic accesses to [2.2]paracyclophane-based derivatives for different applications in materials sciences and supramolecular chemistry in order to exploit transannular communication, steric demand and chirality. In this regard, the first [2.2]paracyclophane-based thermally activated delayed fluorescence (TADF) emitters were developed, chiral chemical vapor deposition (CVD) monomers were synthesized and a new supramolecular guest was synthetically established. During these synthetic endeavors, chemical peculiarities of the [2.2]paracyclophane were observed and investigated, leading to the discovery of para-selective C–H activation and a synthetic access to the novel (1,7)carbazolophane.