Fluorescent Coating through Melanisation of Merocyanine Based on Catechol Chemistry

In this study, we present a novel approach for synthesising a merocyanine (MC) compound that integrates gallol and a near-infrared (NIR) fluorophore using a straightforward method. We conduct a comprehensive structural analysis to elucidate the specific roles of each functional group during monomer synthesis and their effects on the properties of both the spiropyran (SP) and MC forms, particularly their fluorescence. As a proof of concept, we explore the use of these compounds in formulating innovative fluorescent polymeric coatings by melanising catechol and gallol moieties on various substrates, including glass, a cupronickel coin, and an organic polymer. To our knowledge, this is the first report of a bioinspired approach utilizing the melanisation of a catechol and gallol moiety containing merocyanine.