Introducing substituents onto SWNT sidewalls increases their solubility and tunes their properties. Controlling the degree of functionalization is important because the addition of numerous functional groups on the sidewall degrades their intrinsic useful electronic properties. We examined the synthesis and characterization of sidewall-functionalized SWNTs in this study. The functionalized SWNTs ((1)R-SWNTs-(2)R) were prepared in a one-pot reaction of SWNTs with alkyllithium ((1)RLi) followed by alkyl bromide ((2)RBr). The functionalized SWNTs were characterized by the absorption and Raman spectroscopy and thermogravimetric analysis. Not only the total number of functional groups introduced on the SWNT sidewall (formula mass: (1)R = (2)R) but also the ratio of (2)R to (1)R in the functionalized SWNTs (formula mass: (1)R ≠ (2)R) having two different substituents were clarified using the relation between results of Raman spectroscopy and thermogravimetric analysis. Results show that the degree of functionalization of (2)R to (1)R in (1)R-SWNTs-(2)R can be well controlled by the bulkiness of the alkyl groups of (1)RLi and (2)RBr. Moreover, substituent effects of reductive alkylation and reductive silylation of SWNTs via Birch reduction were investigated.

A visible-light-sensitive Ir–Pd photocatalyst is effective for coordination copolymerization of styrene and vinyl ethers. The catalyst drastically accelerates styrene polymerization under visible light irradiation and allows sequence-controlled copolymerization of styrene and vinyl ethers by appropriate switching of the irradiation sequence. The reaction rates of the monomers under irradiated and nonirradiated conditions were compared. Mechanistic studies suggested that the reactions proceeded via a nonradical coordination–insertion mechanism.

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We performed bending tests on crystalline whiskers composed of fullerene C60 molecules by in situ transmission electron microscopy with simultaneous measurement of the applied force by an optical deflection method. A C60 nanowhisker with a diameter of 123 nm was fixed on two fulcra and a concentrated force was applied on the midpoint between the fulcra by the piezomanipulation of a silicon nanotip. The Young's modulus of the nanowhisker was estimated to be 53–69 GPa, 72% smaller than that of C60 nanotubes. The estimated Young's modulus was plotted against the outer diameter along with the moduli estimated previously by buckling tests on C60 nanowhiskers. In this relationship, Young's modulus increased as the outer diameter decreased. The result was in agreement with the core–shell model for C60 nanowhiskers.

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