Incorporation of the Similarly Sized Molecules, Diiodine and Carbon Disulfide, into Cocrystals Formed with the Fullerenes, C60 or C70

Cocrystallization of diiodine and carbon disulfide with the two common fullerenes, C60 and C70, has been examined. The binary cocrystal, C70·I2, readily formed when a solution of diiodine in diethyl ether was layered over C70 dissolved in toluene, chlorobenzene, or 1,2-dichlorobenzene, but no binary cocrystal of diiodine and C60 could be obtained despite persistent efforts. The ternary cocrystal, C70·0.85I2·0.15CS2, which was grown from a carbon disulfide solution of C70 and a benzene solution of diiodine, is isostructural with C70·I2 but has 15% of the diiodine sites replaced with carbon disulfide. In contrast, C70·0.68I2·0.32CS2, which was obtained from diffusion of a cyclohexane solution of diiodine into a carbon disulfide solution of C70, is a unique ternary cocrystal that is not related to any binary cocrystal of C70 with diiodine or carbon disulfide. Crystals of 2C60·2.46CS2·0.54I2 were obtained from a saturated carbon disulfide solution of diiodine and C60. Black crystals of 2C60·2.46CS2·0.54I2 form in a different space group from those of the solvate 2C60·3CS2 but have a very similar structure. Remarkably, diiodine molecules fractionally replace carbon disulfide in only two of the three independent sites within this crystal.