From the Decks to the Bridges: Optoelectronics in [2.2]Paracyclophane Chemistry

In this microreview, we highlight optical properties of [2.2]paracyclophanes (pCps). We demonstrate how the spectroscopic properties that stem from the strained and pi-stacked structure have resulted in pCps being incorporated in materials science and polymer synthesis. As a result of chromophore substitution, internal charge transfer (ICT) between the two rings of the cyclophane core produce frameworks with unique optical properties. Deck-substituted mole-cules and polymers have beensynthesized that possess donor and acceptor groups that affect internal charge transfer (ICT). We also demonstrate that bridge-substituted [2.2] paracylophanes, although not well studied in this context, display unexpected optical properties owing to nonconventional ICT. A highlight is a recent templated solid-state synthesis that affords a pCp that exhibits dramatic red-shifted fluorescence.