Spontaneous Multicomponent Polymerization of Imidazole, Diacetylenic Esters, and Diisocyanates for the Preparation of Poly(β-aminoacrylate)s with Cluster-Induced Emission Characteristics

Multicomponent polymerization (MCP) is an efficient and rapid method for obtaining multifunctional polymeric materials that have been widely developed in recent years. In this work, poly(β-aminoacrylate)s were obtained by spontaneous MCP with the assistance of the C2-amidation of 1-methylimidazole together with diacetylenic esters and diisocyanates. This process can be carried out under mild conditions, such as in a catalyst-free and roomerature environment. Through the systematic optimization of the polymerization conditions, the resultant poly(β-aminoacrylate)s could have molecular weights of up to 24100 g/mol and excellent yields (up to 94%). All the polymers were well-characterized by gel permeation chromatography (GPC), nuclear magnetic resonance (NMR), and Fourier transform infrared spectroscopy (FT-IR), and all the collected data illustrated that the polymerization mechanism corresponds to a model reaction of small molecules. The photophysical property of these obtained polymers indicated that one of the polymers (polymer P1b2a) demonstrated a luminescence capability that was unconventional because no fluorescent emitters were present in its main chains or side chains. A further study suggested that the clustering of diverse subgroups with subsequent electron cloud overlapping, which resulted in molecular conformation rigidification, was primarily responsible for this emission. Thus, the current MCP method will provide guidance for preparing new nonconjugated polymers with cluster-induced emissive functional materials for easily tailored specific applications.