Unilaterally Fluorinated Acenes: Synthesis and Solid‐State Properties

The rapid development of organic electronics is closely related to the availability of molecular materials with specific electronic properties. Here, we introduce a novel synthetic route enabling a unilateral functionalization of acenes along their long side, which is demonstrated by the synthesis of 1,2,10,11,12,14‐hexafluoropentacene (1) and the related 1,2,9,10,11‐pentafluorotetracene (2). Quantum chemical DFT calculations in combination with optical and X‐ray absorption spectroscopy data indicate that the single‐molecule properties of 1 are a connecting link between the organic semiconductor model systems pentacene (PEN) and perfluoropentacene (PFP). In contrast, the crystal structure analysis reveals a different packing motif than for the parent molecules. This can be related to distinct F⋅⋅⋅H interactions identified in the corresponding Hirshfeld surface analysis and also affects solid‐state properties such as the exciton binding energy and the sublimation enthalpy. Regioselective functionalization of acenes: A novel synthetic strategy is introduced that enables a regioselective functionalization of acenes, which is demonstrated using the example of unilaterally substituted fluoroacenes. The packing motif and optoelectronic solid‐state properties of these new materials are compared to the properties of their parental acenes.