No abstract

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.

No abstract

A series of sphere-rod shape amphiphiles, in which a [60]fullerene (C60) sphere was connected to the center of an oligofluorene (OF) rod through a rigid linkage (OF-C60), were designed and synthesized. Alkyl chains of various lengths were attached onto the OFs on both sides of the C60 spheres. These compounds, denoted as alkyl-OF-C60, were fully characterized by (1)H NMR, (13)C NMR, and FTIR spectroscopy and by MALDI-TOF mass spectrometry. The morphologies and structures of their crystals were elucidated by wide-angle X-ray diffraction (WAXD) and by electron diffraction in transmission electron microscopy (TEM). Butyl-OF-C60 forms a monoclinic unit cell (a=1.86, b=3.96, c=2.24 nm; α=γ=90°, β=68°; space group P2), octyl-OF-C60 also forms a monoclinic unit cell (a=2.21, b=4.06, c=1.81 nm; α=γ=90°, β=75.5°; space group C2m), and dodecanyl-OF-C60 forms a triclinic structure (a=1.82, b=4.35, c=2.26 nm; α=93.1°, β=94.5°, γ=92.7°; space group P1). The inequivalent spheres and rods were found to pack into an alternating layered structure of C60 and OF in the crystals, thus resembling a "double-cable" structure. UV/Vis absorption spectroscopy revealed an electron perturbation between the two individual chromophores (C60 and OF) in their ground states. Fluorescence spectroscopy exhibited complete fluorescence quenching of their solutions in toluene, thus suggesting an effective energy transfer from OF to C60. Cyclic voltammetry indicated that the energy-level profiles of C60 and OF remained essentially unchanged. This work has broad implications in terms of understanding the self-assembly and molecular packing of conjugated materials in crystals and has potential applications in organic field-effect transistors and bulk heterojunction solar cells.