Reversible alkali-metal reduction of C60 in liquid ammonia; first observation of near-infrared spectrum of C5–60

Abstract

A new method for the homogeneous redox manipulation of alkali-metal fullerides with a solution of rubidium in liquid ammonia at –40 °C has been used to prepare the C^2–₆₀, C^3–₆₀, C^4–₆₀ and C^5–₆₀ ions, the near IR spectra being recorded at various stages of the titration; the excitation energy of the main band in C^5–₆₀(10 500 cm^–1) is close to that of C^1–₆₀ and the principal band in the C^2–₆₀ spectrum.