Synthesis of 6,13-difluoropentacene

Abstract

6,13-Difluoropentacene was synthesized from 1,4-difluorobenzene. Friedel–Crafts annulation of the latter with phthalic anhydride and subsequent reduction of the anthraquinone gave 1,4-difluoroanthracene. After ortho-lithiation and reaction with phthalic anhydride a carboxylic acid was obtained whose Friedel–Crafts acylation and subsequent reductive removal of the oxygen-functionalities resulted in the formation of the target compound. The HOMO–LUMO gap of 6,13-difluoropentacene was determined via UV–vis spectroscopy and compared to other fluorinated pentacenes.

Chemical Doping by Fluorination and Its Impact on All Energy Levels of π-Conjugated Systems

“…All XPS and NEXAFS measurements are performed at the HE-SGM dipole beamline of the synchrotron storage ring BESSY II on in situ-prepared molecular multilayer films (for experimental details see the Supporting Information (SI)). Although the synthesis of 6,13-difluoropentacene (F 2 PEN) has recently been demonstrated, 38 the available amount was too little to enable film preparations. Therefore, Cl 2 PEN films are examined instead and F 2 PEN is analyzed only on a theoretical level for comparison.…”