POLYHYDROGENATION OF [60]FULLERENES AND [70]FULLERENES WITH ZN HCL AND ZN/DCL/

Previous work on polyhydrogenation of fullerenes leading to C60H36 and C70H36 as the main products is reviewed. The most probable structures of these species, based on their aromaticities, are presented. Zinc/c oncentrated HCl is shown to be an excellent and rapid reducing agent f or benzene or toluene solutions of fullerenes at room temperature. The polyhydrogenated species are unstable towards light and undergo oxida tive degradation, with, in the case of C60H36, formation of C60H18 as an intermediate. Reduction of these fullerenes by zinc/concentrated DC l gives C60H44 and C70H48 as the highest hydrogenated products; the gr eater incorporation of deuterium is attributed to the greater C-D bond energy. In the absence of light and oxygen, C60H36 exhibits high ther mal stability. Attempted further reduction of C60H36 leads to formatio n of trimethylene adducts; these are also formed on reduction of [84] fullerenes which gives C84H48 as the main product.