Angewandte Chemie International Edition · 2018 · 21 citations · 23 references
Natural SciencesChemistryMaterials SciencePolymer ChemistryStructural BiologySupramolecular ChemistryIntermolecular InteractionsMacromolecular AssemblyMacromolecular StructureSelf-assemblySupramolecular MaterialsSupramolecular PolymersAromatic Molecular Self-assemblyCharge DelocalizationElectron DelocalizationExciton DelocalizationSandwich StructuresTorsional DynamicsTorsional Rigidityπ-π Interactions
Abstract Exciton and charge delocalization across π‐stacked assemblies is of importance in biological systems and functional polymeric materials. To examine the requirements for exciton and hole stabilization, cofacial bifluorene ( F 2) torsionomers were designed, synthesized, and characterized: unhindered (model) Me F 2, sterically hindered tBu F 2, and cyclophane‐like C F 2, where fluorenes are locked in a perfect sandwich orientation via two methylene linkers. This set of bichromophores with varied torsional rigidity and orbital overlap shows that exciton stabilization requires a perfect sandwich‐like arrangement, as seen by strong excimeric‐like emission only in C F 2 and Me F 2. In contrast, hole delocalization is less geometrically restrictive and occurs even in sterically hindered tBu F 2, as judged by 160 mV hole stabilization and a near‐IR band in the spectrum of its cation radical. These findings underscore the diverse requirements for charge and energy delocalization across π‐stacked assemblies.
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Long-range charge transport in single G-quadruplex DNA molecules
Gideon I. Livshits, Avigail Stern, Dvir Rotem et al. · Nature Nanotechnology · 2014 · 263 citations