Synthesis, isolation via self-assembly, and single-molecule observation of a [60]fullerene-end-capped isotactic poly(methyl methacrylate).

We report the preparation and single-molecule observation of a high molecular weight C60-end-capped, stereoregular poly(methyl methacrylate) (PMMA-C60) with a precisely controlled structure. The highly isotactic PMMA-C60 (mm = 98%) with a narrow molecular weight distribution was synthesized by the stereospecific anionic living polymerization of tert-butyl methacrylate followed by end-capping with C60, hydrolysis of the pendant esters, and methylation with CH3I. Although the functionality of the C60 (fC60) of the as-prepared isotactic PMMA was imperfect (ca. 40%), the completely C60-end-capped PMMA (fC60 approximately 100%) was successfully isolated through self-assembly of the PMMA-C60 in a polar solvent by size exclusion chromatography. Furthermore, the individual PMMA chains together with the covalently bonded terminal C60 molecules were clearly visualized by atomic force microscopy, which definitely showed the structure of the isolated PMMA-C60.