Synthesis of Sulfur-Containing Polyacetylenes and Fabrication of Their Hybrids with ZnO Nanoparticles

It has been a challenge to synthesize thiol-functionalized polyacetylenes because of the poisoning effect of mercapto group on the early transition-metal catalysts. Rhodium complexes such as [Rh(cod)Cl]2 can catalyze the polymerizations but the products are insoluble and intractable. In this work, we tackled this challenge. Sulfur-containing polyacetylenes with macroscopic processability were successfully synthesized by separating thiol pendant from polyene backbone with a flexible spacer (in P1), capping free mercapto group with acetyl or alkyl group (in P2 or P3), and using a zwitterionic complex Rh+[η6-C6H5(nbd)B–(C6H5)3] as catalyst. The soluble polymers were characterized by NMR, IR, UV, PL, and TGA analyses. Due to the specific interactions between thiol group and zinc cation, ZnO nanoparticles were chemisorbed onto the surfaces of polymer films, as verified by AFM analysis. Polymer P2 and ZnO nanoparticles could be readily hybridized by simply mixing the two components in an organic solvent such as chloroform, THF, or DMF. SEM images revealed that the morphology of the film cast from the solution of the P2/ZnO hybrid was dominated by well-dispersed nanoparticles and smooth surface.