Electronic Materials: An Antiaromatic Propeller Made from the Four‐Fold Fusion of Tetraoxa[8]circulene and Perylene Diimides. (25th October 2022)

• Record Type: Journal Article
• Authors: Pedersen, Viktor B. R.; Pedersen, Stephan K.; Jin, Zexin; Kofod, Nicolaj; Laursen, Bo W.; Baryshnikov, Glib V.; Nuckolls, Colin; Pittelkow, Michael
• Is Part Of: Angewandte Chemie. Volume 134:Number 48(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-10-25
• Subjects: Antiaromaticity -- Aromaticity -- DFT -- Solar Cells -- Spectroscopy; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.202212293
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: The synthesis of an antiaromatic tetraoxa[8]circulene annulated with four perylene diimides (PDI), giving a dynamic non‐planar π‐conjugated system, is described. The molecule contains 32 aromatic rings surrounding one formally antiaromatic planarized cyclooctatetraene (COT). The intense absorption ( ϵ =3.35×10 5 M −1 cm −1 in CH2 Cl2 ) and emission bands are assigned to internal charge‐transfer transitions in the combined PDI‐circulene π‐system. The spectroscopic data is supported by density functional theory calculations, and nuclear independent chemical shift calculation indicate that the antiaromatic COT has increased aromaticity in the reduced state. Electrochemical studies show that the compound can reversibly reach the tetra‐ and octa‐anionic states by reduction of the four PDI units, and the deca‐anionic state by reduction of the central COT ring. The material functions effectively in bulk hetero junction solar cells as a non‐fullerene acceptor, reaching a power conversion efficiency of 6.4 %. Abstract : Annelating the antiaromatic tetraoxa[8]circulene with four perylenediimide units yields an intensely absorbing and emissive charge‐transfer molecule. The aromatic/antiaromatic character of neutral and charged species and the incorporation in bulk hetero junction solar cell (power conversion efficiency of 6.4 %) is described.