Photoelectroactive Corrole Monomer Functionalized with a Triphenylamine–Chalcone Derivative: Synthesis, Electropolymerization, and Electrochromic Applications

In this work, we report a divergent synthesis of a novel corrole macrocycle featuring a T-shaped geometry and peripheral functionalization with triphenylamine (TPA) units. The synthesis began with 5-(pentafluorophenyl)dipyrromethane, prepared via a green protocol by Dehaen. This aryldipyrromethane was condensed with pentafluorobenzaldehyde in a MeOH/HCl aqueous mixture to yield a bilane intermediate, which was subsequently oxidized with DDQ to afford the target corrole bearing three pentafluorophenyl groups at the meso positions. In parallel, a TPA-based chalcone derivative was synthesized through Claisen–Schmidt condensation. Finally, a regioselective nucleophilic aromatic substitution in dry DMF using K₂CO₃ as base displaced the para-fluorine atoms, delivering the functionalized monomer in high yield. This molecule features a photoactive corrole core covalently linked to the electron-donating and electropolymerizable TPA moiety, making it a promising building block for photoactive and electroactive materials. The TPA groups were selected to promote electrochemical radical coupling: upon anodic oxidation, TPA radical cations dimerize to form tetraphenylbenzidine (TPB) linkages, producing covalently connected corrole films on Pt and ITO electrodes. Electropolymerization by cyclic voltammetry showed steadily increasing redox currents, consistent with conductive polymer growth. CV and UV–Vis spectroelectrochemistry confirmed retention of the corrole macrocycle (Soret and Q bands) and revealed additional absorptions at 300–350 nm from TPA/TPB species. Spectroelectrochemical switching exhibited reversible green-to-blue color changes, demonstrating strong electrochromic behavior and potential for electrochromic device applications.