Diselenide–yne polymerization for multifunctional selenium-containing hyperbranched polymers

Abstract

Exploration of new strategies for the preparation of novel polymer materials with diverse topological structures and functions is a subject of enduring interest in the area of polymer science. In this work, diselenide–yne polymerization for the efficient preparation of selenium-containing hyperbranched polymers (Se-HBPs) was established, which could proceed with 100% atom efficiency under blue light irradiation without any external catalyst. Through systematic optimization of the reaction conditions, a series of Se-HBPs with controllable molecular weights and well-defined structures were obtained in high yield (up to 99%) and stereoselectivity (E/Z = 93 : 7). This type of polymer has degrees of branching (DB) almost as high as that of dendrimers because each unit is either terminal or fully branched. During the mild and efficient diselenide–yne polymerization, the molecular weight and terminal group of the hyperbranched polymer could be adjusted by an AB₂ + A type copolymerization strategy, providing a powerful tool to tailor the properties of hyperbranched polymers. Fluorescent, aggregation-induced emission (AIE) and amphipathic Se-HBPs could be prepared in a one-pot reaction. Notably, the AIE-terminal Se-HBPs showed a “see-saw” fluorescence performance via the combination of AIE and aggregation-caused quenching (ACQ). The amphipathic Se-HBPs could self-assemble to give nanoparticles, which showed good oxidation-responsive properties. Moreover, colloid gold nanoparticles could be prepared by utilizing these Se-HBPs as both stabilizers and reductants, which exhibited sensitive oxidative response to 0.01 wt% H₂O₂. We believe that the simplicity and versatility of diselenide–alkyne polymerization will open up enormous opportunities for preparing multifunctional smart polymeric materials.