New [2,2]fluorenophanes Give Insights into Asymmetric Charge Transfer‐Mediated Exciton Delocalization along the Π‐π Packing Direction

A series of new [2,2]fluorenophanes has been synthesized and characterized; among them, molecules of crystallographically asymmetric anti-[2.2](1,4)(4,1)fluorenophane (K2C-2) aggregate to form one-dimensional supramolecular chain structures through effective intermolecular pi-pi overlapping. This, in combination with the synergistic intramolecular pi-pi interaction, leads to prominent dual emission mediated by charge transfer (CT) exciton delocalization. Support of this new insight is given by mapping the transition density along the pi-pi packing direction where the intramolecular excitation and intermolecular CT coexist in K2C-2.