Fluorescent bowl-shaped nanoparticles from ‘clicked’ porphyrin–polymer conjugates

We report the synthesis and post-synthetic modification of a library of hydrophilic and hydrophobic ‘clicked’ triazole-linked porphyrin–polymer conjugates (PPCs). A detailed study of the reaction conditions was undertaken, revealing a competition between copper(I)-catalysed and thermal Huisgen azide–alkyne cycloaddition pathways. Remarkably, porphyrin–polystyrene conjugates assembled into fluorescent bowl-shaped nanoparticles whose morphology depended on the porphyrin–polystyrene ratio of constituent PPC. Nanoparticles prepared from freebase PPCs exhibited colorimetric aqueous pH sensing, indicating that the PPC nanoparticles may be a useful platform for chemical sensing applications.