Convenient syntheses of fullerynes for 'clicking' into fullerene polymers

Alkyne-functionalized fullerenes (fullerynes) were designed and conveniently synthesized via Bingel reaction in one step with high yields. They were used to react with azido-functionalized polystyrene (PS) via Huisgen [3 + 2] cycloaddition 'click' chemistry to form two fullerene polymers: one with C₆₀ tethered to the end of a PS chain (C₆₀-1PS) and the other with C₆₀ tethered at the junction point of two PS chains of identical molecular weight (C₆₀-2PS). The fullerene polymers were characterized by ¹H NMR, ¹³C NMR, FT-IR, MALDI-TOF mass spectrometry and SEC. The results showed that the fullerene polymers are well-defined with narrow polydispersity and high fullerene functionality. Besides, aggregation of C₆₀ in THF was observed in the SEC traces. The optical properties of the fullerene polymers were studied by UV-Vis absorption spectroscopy, and the results suggested that the PS chain(s) on the fullerene core has no remarkable effect on the optic property of C₆₀. The thermal properties of the fullerene polymers were studied by TGA and DSC, and the results indicated that the two fullerene polymers with different C₆₀ content and distinct molecular topology may have different self-assemble architectures in the solid state. The well-defined fullerene polymers can be used as model compounds to study the self-assemble architecture of shape amphiphiles based on polymer-tethered molecular nanoparticles.