Single Component Polymerization of Diisocyanoacetates toward Polyimidazoles

The polymerization of triple-bond building blocks will generate functional polymers owing to their unsaturated backbones, which facilitate the electron delocation within the main chains. Currently, the research focus in this area is the alkyne-based polymerization, and the carbon-nitrogen triple-bond based polymerization to produce stable nitrogen-containing polymers is rarely reported. In this paper, a new polymerization of diisocyanoacetate was successfully established. The silver acetate-catalyzed polymerization of diisocyanoacetate in the acetonitrile or DMF readily produced soluble polyimidazoles with high molecular weights (M-w up to 32500) in excellent yields (up to 94%) at room temperature after 2 h. Moreover, this polymerization performed in a single component fashion, which shows remarkable advantages over the traditional two- or multicomponent ones. In addition, the resultant polyimidazoles could be postfunctionalized to yield ionized polyelectrolytes and could feature the aggregation-induced emission (AIE) characteristics by incorporation of an AIE-active tetraphenylethene moiety in its polymer chains. This single component polymerization will become a powerful tool for the preparation of polyimidazoles and be potentially applicable in materials and biological fields.