Fullerenes as Metal-Free Hydrogenation Catalysts

Significance

A highly efficient C₆₀-fullerene-catalyzed hydrogenation of nitrobenzene is reported. The reaction pathway could be either driven by light, utilizing UV irradiation and atmospheric hydrogen, or by pressure, affording the aniline at elevated temperatures and 5 MPa hydrogen. In the latter case a mixture of C₆₀ and its corresponding monoanion C₆₀ ^- proved to be a more efficient catalyst. During the pressure-driven reaction process azo- and azoxybenzene could be observed as side products; however, the separated catalytic hydrogenations of those species were not successful compared to the original transformation, proposing a direct ­reaction route without intermediates rather than a sequential reduction mechanism.