Catalyst-Free Thiol-Yne Click Polymerization: A Powerful and Facile Tool for Preparation of Functional Poly(vinylene sulfide)s

The "thio-click" polymerization is a well-expanded concept of click polymerization. Among the click polymerizations, the thiol-yne click polymerization is less developed and still in its infancy stage. In general, UV light, elevated temperature, amine, or transition metal complexes is needed to catalyze the thiol-yne click polymerization, which greatly complicates the experimental operation and limits its application. In this work, a facile and powerful thiol-yne click polymerization was developed, which could be carried out under very mild conditions without using external catalyst. Simply mixing the aromatic diynes (1a-1e) and dithiols (2-4) with equivalent molar ratio in THF at 30 degrees C will readily produce soluble and regioregular functional poly(vinylene sulfide)s (PIa-PIe, PII, and PIII) with high molecular weights (M-w, up to 85 200) in excellent yields (up to 97%) after as short as 2 h. Furthermore, no double addition product of an ethynyl group was found. This catalyst-free thiol-yne click polymerization has remarkably simplified the reaction conditions and will facilitate the preparation of functional materials applied in diverse areas.