Analytical Sciences

Diffusion Coefficients of C₆₀ and C₆₀^- in Benzonitrile and Dichloromethane Solutions Containing Tetrabutylammonium Perchlorate, Measured by Potential-step Chronoamperometry

Yukihiro HISHIDA, Minako NISHI, Yukie BABA, and Haruko IKEUCHI

Department of Chemistry, Faculty of Science and Technology, Sophia University, 7-1, Kioi-cho, Chiyoda-ku, Tokyo 102-8554, Japan

The diffusion coefficients of C₆₀ in dichloromethane and benzonitrile solutions containing 0.1 M tetrabutylammonium perchlorate were determined by single potential-step chronoamperometry at small disk electrodes. The diffusion coefficients of C₆₀ were obtained by curve fitting of the chronoamperograms to a theoretical equation by Shoup and Szabo. The values were (1.4 ± 0.3) × 10^-9 and (4.1 ± 0.3) × 10^-10 m² s^-1, respectively (the errors are 95% confidence limits). The diffusion coefficients of C₆₀^- in these solutions were measured by double potential-step chronoamperometry. The ratios of the diffusion coefficients of C₆₀ to those of C₆₀^- were obtained from theoretical curves of the ratios of the current at the second potential step to the current at the first one. The values of the ratios were 1.2 ± 0.2 and 1.0 ± 0.3, respectively.

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