Multicomponent Polymerization of Alkynes, Isocyanides, and Isocyanates toward Heterocyclic Polymers

Multicomponent polymerization (MCP) based on isocyanides, among the tremendous synthetic methodologies, is a powerful tool for the synthesis of functional heterocyclic polymers such as poly(maleimide)s (PMDs), which should be further developed. In this work, an atom-economic and catalyst-free MCP of activated alkynes, diisocyanides, and diisocyanates was fully explored. PMDs with high weight-average molecular weights (M-w up to 29,000) were facilely produced in satisfactory yields (up to 85%). The resultant polymers show excellent solubility, high thermal stability, and good film-forming ability, and their thin films possess high refraction indices in a range of 1.614-1.710 at 632.8 nm. Therefore, this work not only supplements the isocyanide-based MCPs but also enriches the family of polymerization reactions based on triple-bond building blocks.