Bulk Production of a Strong Covalently Linked (C60H x )2 Dimer

The high-pressure treatment of C60 in an H2 atmosphere at high temperatures leads to the efficient formation of a covalently bound dimer and some oligomeric species. The resulting hydrogenated C120 is an example of the bulk production of covalently bound derivatized fullerene cores. Matrix-assisted laser desorption/ionization in conjunction with reflectron time-of-flight mass spectrometry has been applied to the product analysis. The dissociation pattern of selected C120H2 x + ions (x > 30) indicates the dimeric structure of (C60H x )2, as opposed to a giant hydrofullerene species possessing a fused C120 core. However, the results also clearly indicate a much stronger bonding (multiple σ bonding) between the C60H x units than present in cycloaddition products. Evidence of a covalently linked dimer was obtained in labeling experiments, on the basis of which any laser-induced gas-phase aggregation of the C60H x monomer during the analysis is discounted.