Reaction of hydrogen gas with C ₆₀ at elevated pressure and temperature: Hydrogenation and cage fragmentation

Products of the reaction of C ₆₀ with H ₂ gas have been monitored by high-resolution atmospheric pressure photoionization Fourier transform ion cyclotron resonance mass spectrometry (APPI FT-ICR MS), X-ray diffraction, and IR spectroscopy as a function of hydrogénation period. Samples were synthesized at 673 K and 120 bar hydrogen pressure for hydrogenation periods between 300 and 5000 min, resulting in the formation of hydrofullerene mixtures with hydrogen content ranging from 1.6 to 5.3 wt%. Highly reduced C ₆₀H _x (x > 36-40) and products of their fragmentation were identified in these samples by APPI FT-ICR MS. A sharp change in structure was observed for samples with at least 5.0 wt% of hydrogen. Low-mass (300-500 Da) hydrogenation products not observed by prior field desorption (FD) FT-ICR MS were detected by APPI FT-ICR MS and their elemental compositions obtained for the first time. Synthetic and analytical fragmentation pathways are discussed.