Attachment of a 1,8‐Naphthalimide Moiety to a Conjugated Polythiophene Efficiently Improves the Sensing Abilities of Naphthalimide‐Based Materials

Abstract

AbstractA novel polythiophene‐based conjugated polymer bearing 1,8‐naphthalimide‐based pendants is prepared by a two‐step modification of regioregular poly[3‐(6‐bromohexyl)thiophene] involving a nucleophilic substitution reaction of the bromide end‐groups with sodium azide followed by a robust, copper‐catalyzed Huisgen click reaction with a novel 1,8‐naphthalinmide derivative containing an active, N‐substituted propyne group. Both the polymer and the highly luminescent‐active synthesized dye are extensively studied in solution by UV–vis spectroscopy, photoluminescence, NMR, light‐scattering and isothermal titration calorimetry. The materials prepared are considered potential chemosensors for different transition metals, such as Fe2+, Co2+, Ni2+, Cu2+, Zn2+, and Cd2+. Luminescence quenching shows that these materials have a higher sensitivity to Fe2+ than to the other metal ions tested. Moreover, the 1,8‐naphthalimide‐based conjugated polymer is more efficiently quenched by Fe2+ metal ions, at a significantly lower concentration and with a higher binding constant than its parent 1,8‐naphthalimide derivative, thus indicating a high potential for sensor development.