Fluorescence Turn‐On Corrosion Inhibitor with a Tetraphenylethylene Framework: Corrosion Inhibition and Theoretical Calculations

Abstract Luminogens with aggregation‐induced emission (AIE) properties have received growing interest recently, due to their unique photophysical properties and wide applications. However, the adsorption and fluorescent behaviors of AIE compounds (AIEgens) have been rarely explored on metal surface. Herein, a zwitterionic compound 1 incorporating tetraphenylethylene (TPE) cation and SCN⁻ anion was developed integrating AIE and corrosion inhibition. Weight loss experiment and electrochemical studies manifest 1 is an effective corrosion inhibitor for brass in 0.5 m H₂SO₄ with inhibition efficiency achieving over 99%. Meanwhile, intensive fluorescence was observed after adsorption of 1 on brass surface, facilitating fluorescent visualization and a new strategy for corrosion inhibition with precise dosing. In contrast, compound 2 with identical TPE cation and SO₄²⁻ anion has negligible corrosion inhibition effect. The differences of adsorption and fluorescent behaviors between 1 and 2 were attributed to hard and soft acids and bases theory and electrostatic attraction. The corrosion inhibition mechanism was further investigated by comprehensive calculations. This work provides a new approach for visualization of corrosion protection, and enriches understanding of behaviors and functionalities of AIEgens on metal surface.