Core-Twisted, Cationic Perylene Diimides; Homochiral Dimerization and Chiroptical Anion Sensing

Core-twisted perylene diimides (PDIs) are chiral organic dyes that may be exploited for self-assembled chiroptical materials or for the enantioselective recognition and sensing of chiral substrates. Discrete self-assembled dimers and host-guest complexes of core-twisted perylene diimides are important for furthering our understanding of this supramolecular chemistry, yet they are rare because the twisted perylene core significantly weakens intermolecular π-π interactions with the PDI's π-surface. To address this challenge, we have installed hydrogen bond donor groups in the PDI's bay positions, which direct the formation of a robust, co-facial and homochiral intermolecular PDI dimer. The structure of this discrete dimer is distinct from previous aggregates of non-planar PDIs that utilize the imide position for hydrogen bonding. We also uncover the potential of core-twisted, dicationic PDIs for the enantioselective recognition and chiroptical sensing of chiral anions and investigate the basis of this response via chiral complementarity in the discrete host-guest complex.