Reversible Nucleophilic\nRing-Opening of Tetraoxapentacene\nDerivatives: Accessing New Materials for Thermally Activated Delayed\nFluorescence

We report the unexpected nucleophilic ring-opening reaction\nof\nelectron deficient dioxins in the presence of carbazole under basic\nconditions. This nucleophilic ring-opening reaction is reversible\nunder basic conditions in the absence of nucleophiles. Further, we\ndemonstrate that this unexpected reactivity can be used to prepare\nnovel donor–acceptor compounds that are emissive in solution\nand as thin films and exhibit thermally activated delayed fluorescence\n(TADF).