Economic Sulfur Conversion to Polythioamides through Multicomponent Polymerizations of Sulfur, Dibromides, and Diamines

Polythioamides, as a new group of sulfur-containing polymer materials with unique optical property and metal coordination ability, have garnered increasing research interests recently, whose cost-effective synthetic approaches with potential scale-up production are highly desired. In this work, the efficient N-methylpiperidine (NMP)-assisted reaction of elemental sulfur, benzyl bromide, and amine was demonstrated to produce thioamides in 85-89% yields. The NMP-assisted multicomponent polymerization of elemental sulfur, dibromides, and diamines were hence developed to provide the economic access to a series of polythioamides with high molecular weights (Mws up to 16 900 g/mol) and excellent yields (up to 97%). The MCP was featured with high efficiency, mild condition in air, simple procedure, robustness, and all three monomers were facilely available commercial raw materials, enabling 10 gram-scale synthesis of these polythioamides. These polythioamides showed high glass transition temperatures, high refractivity index at 589 nm at 1.7135-1.7771, which can also be used to enrich Au3+ from aqueous solution with high enrichment capacity (up to 495 mgAu3+/g), high selectivity and efficiency, demonstrating their potential economic values. The MCP of elemental sulfur, dibromides, and diamines hence offer a versatile synthetic strategy to produce cost-effective, sustainable functional polythioamides, accelerating the development of the profitable polymer materials originated from sulfur.