Formation of buckministerfullerene phenylene derivatives in the gas phase

The gas‐phase chemistry of Fe(C6H4)n+ (n = 1–6) with C60 is studied by using Fourier transform ion cyclotron resonance mass spectrometry. The formation of some ionic phenylene derivatives and metallacyclic derivatives of C60 is observed. Specifically, Fe+, generated by laser desorption, reacts with chlorobenzene to form iron‐benzyne, FeC6H4+, which initiates further reactions with chlorobenzene to form Fe(C6H4) 2–6+ and (C6H4) 2–5+. Fe(C6H4) 1–4+ react with C60 to form metalated fullerene derivatives, C60Fe(C6H4) 1–4+. C60Fe(C6H4) 1, 2+ undergo a demetalation reaction with chlorobenzene to yield the fullerene phenylene derivatives C60(C6H4) 1, 2+, 8 and 9, through formation of CC bonds with C60. CID experiments and kinetic analysis indicate that each of the C60Fe(C6H4) 1, 2+ species consists of a single isomer, presumably the metallacycles 12 and 14. Consistent with the typical reactions of metal‐benzyne complexes with alkenes in the condensed phase, these metallacyclic structures are believed to be formed through coupling of one of the double bonds at the 6,6 ring junction in C60 with an FeC σ bond of Fe(benzyne)+. These results are consistent with the notion that C60 acts like an electron deficient alkene rather than an aromatic molecule, and suggest a possible synthetic route to prepare this type of metallo‐C60 derivatives in the condensed phase. Finally, ligand displacement reactions yield a bond dissociation energy of D°(Fe+C60) = 44 ± 7 kcal/mol.