Curved Perylene Diimides Fused with Seven-Membered Rings

Curved perylene diimides fused with seven-membered rings have been synthesized using a regioselective bay-functionalization method and Pd-catalyzed intramolecular C-H/C-Br coupling reaction. X-Ray analysis and temperature-dependent NMR spectroscopy revealed the curved molecular structure with a certain degree of conformational flexibility. The curved and expanded pi-conjugation altered the electronic properties while retaining the intrinsic properties of the parent perylene diimide. Despite the absence of solubilizing N-substituents, the curved perylene diimides showed sufficient solubility for application in solution-processed organic photovoltaic devices. The devices showed superior performance with a power conversion efficiency of up to 2.76% due to suppressed charge recombination. Our detailed investigations suggest that the introduction of a curved structure enables the removal of the bulky N-substituents, which is an effective way to achieve a thin-film morphology suitable for photoelectric conversion.

Automated summary

Synthesis of curved perylene diimides fused with seven-membered rings using regioselective bay-functionalization method and Pd-catalyzed intramolecular C-H/C-Br coupling reaction was achieved. X-Ray analysis and temperature-dependent NMR spectroscopy confirmed the curved molecular structure with conformational flexibility. The introduction of curved structure enabled removal of bulky N-substituents, enhancing solubility and power conversion efficiency in organic photovoltaic devices.