MALDI Mass Spectrometry of Fullero[C60]tetrahydropyridines

Abstract

Mass spectra of positive and negative MALDI ions of the series of fullero[C₆₀] tetrahydropyridines with different substituents in a heterocycle are systematically studied for the first time. All mass spectra contain C₆₀ fullerene peaks as a result of the reduction of fullero[C₆₀]tetrahydropyridines. The intensities of the protonated molecular ions’ [M + H]⁺ peaks are highest in the mass spectra of positive ions of the studied compounds, while molecular radical ion [M]⁺ is less intense. The intensities of the peaks of molecular radical ion [M]^– are highest in the mass spectra of the negative ions. The [C₆₀C₂H₅] ions formed during the decay of the molecular ions with the detachment of neutral nitrile molecules is characteristic of all compounds. Using DFT quantum–chemical calculations (PBE/3z), the energies of the highest (HOMO) and lowest unoccupied molecular orbitals (LUMO) are determined for fullero[C₆₀]tetrahydropyridines with substituents in the heterocycle.