Iron Sulfido Derivatives of the Fullerenes C₆₀ and C₇₀

Toluene solutions of C₆₀ react upon UV irradiation with Fe₂S₂(CO)₆ to give C₆₀[S₂Fe₂(CO)₆]_n where n = 1-6. C₆₀[S₂Fe₂(CO)₆]_n where n = 1-3 have been isolated and characterized. Crystallographic studies of C₆₀S₂Fe₂-(CO)₆ show that the S-S bond of the Fe₂ reagent is cleaved to give a dithiolate with idealized C_2v symmetry. The addition occurred at a 6,6 fusion, and the metrical details show that the Fe₂ portion of the molecule resembles C₂H₄S₂Fe₂(CO)₆. IR spectroscopic measurements indicate that the Fe₂(CO)₆ subunits in the multiple-addition species (n > 1) interact only weakly. UV-vis spectra of the adducts show a shift to shorter wavelength with addition of each S₂Fe₂(CO)₆ unit. Photoaddition of the phosphine complex Fe₂S₂(CO)₅(PPh₃) to C₆₀ gave C₆₀-[S₂Fe₂(CO)₅(PPh ₃)]_n, where n = 1-3. ³¹P{¹H} NMR studies show that the double adduct consists of multiple isomers. Photoaddition of Fe₂S₂(CO)₆ to C₇₀ gave a series of adducts C₇₀[S₂Fe₂(CO)₆]_n where n = 1-4. HPLC analyses show one, four, and three isomers for the adducts, respectively.