Crystal structure of the 4 + 2 cyclo-adduct of photooxidized anthracene and C60 fullerene.

The structure of the title compound, 5,6-[(1R,10S)-2,9-dioxatri-cyclo-[8.6.0(3,8).0(11,16)]hexa-decane-1,10-di-yl]-(C60-Ih)[5,6]fullerene methane-dithione 0.1-solvate, C74H10O2·0.1CS2, has tetra-gonal (P42/n) symmetry at 100 K. It has a unique eight-membered ring, with two incorporated O atoms in place of the original central ring of the anthracene. The distortion of the mol-ecular geometry around the cyclo-adduct bonds corresponds to that seen in related fullerene derivatives. Close packing of the adduct forms cavities partially filled with disordered carbon di-sulfide solvent mol-ecule. The 41% occupancy of the cavities yields an overall 1:0.103 adduct-solvent ratio. Reaction steps are described as light-assisted singlet-oxygen generation, peroxide, epoxide and dioxocin derivative formation and the final step of thermally activated cyclo-addition.