Photo- and redoxfunctional cyclophanes, macrocycles, and catenanes based on aromatic bisimides

Publication date: Available online 27 March 2017 Source:Journal of Photochemistry and Photobiology C: Photochemistry Reviews Author(s): Peter Spenst, Frank Würthner Aromatic bis(dicarboximides), abbreviated as bisimides or diimides, are interesting building blocks for the construction of electro- and photofunctional architectures. The possibility of reversible reduction of aromatic molecules equipped with imide units at modest redox potentials between about –1.3 and –1.0V vs. the ferrocenium/ferrocene redox couple could be exploited by a broad variety of electroactive cyclophanes, macrocycles and catenane scaffolds to direct molecular motions by charging the systems with electrons. Whilst most of the work in this field has been accomplished for the smaller pyromellitic (PyBI) and naphthalene bisimides (NBI), the larger perylene bisimides (PBI) offered an entry into the field of photofunctional systems. Here cyclophanes with closely stacked PBI units provided insight into exciton coupling in homo and hetero dye dimers or ultrafast loss of coherence of the initially populated exciton states to give excimers or symmetry-broken charge separated states. In contrast for PBI cyclophanes with larger cavities, guest encapsulation could efficiently modulate the photophysical properties of highly fluorescent host-guest complexes (upon incorporation of electron-poor aromatic guest molecules) to fully quenched systems (upon incorporation of electron-rich molecules). For larger PB...

Source: Journal of Photochemistry and Photobiology C: Photochemistry Reviews - March 28, 2017 Category: Chemistry Source Type: research