Reluctant cocrystal growth of fullerenes with nickel dithiolene complexes

Abstract

Attempts to form covalent CS bonds between fullerenes and dithiolene complexes, Ni(S2C2R2)2, lead only to the formation of the cocrystals C60·Ni(S2C2Ph2)2·0.5C7H8 and 2C70·2Ni(S2C2Ph2)2·C7H8. Both cocrystals contained pairs of Ni(S2C2Ph2)2 molecules that make offset face-to-face contact with Ni⋯Ni distances of 3.8793(5) Å in the C60 crystal and 3.7529(9) and 3.7983(9) Å in the C70 crystal. The fullerenes are nestled near the NiS4 portion of the Ni(S2C2Ph2)2 molecules. In 2C70·2Ni(S2C2Ph2)2·C7H8 there are two distinctly different interactions between the fullerene and the nickel complex. In one C70·Ni(S2C2Ph2)2 pair, the long axis of the fullerene is nearly parallel to the long axis of the nickel complex, while in the other pair, the long axis of the C70 cage is oriented nearly perpendicular to the long axis of the nickel complex. Thus, the immediate intimate contact between molecules such as fullerenes and flat molecules like Ni(S2C2Ph2)2 is not fixed, but can be altered by other aspects of crystal packing. The structure of a new solvated form of Ni(S2C2Ph2)2, Ni(S2C2Ph2)2·2C6H6, is also reported.