Gas-Phase Reactivity of Polycyclic Aromatic Hydrocarbon Radical Cations with Compounds that are Models of DNA Bases

Radical cations are known to take part in biological chemistry. For example, polycyclic aromatic hydrocarbons (PAH) may be activated to radical cations enroute to damaging DNA and causing cancer. Mass spectrometry can be used to generate radical cations in the gas phase and study their inherent reactivity. It follows that mass spectrometry can play a role in establishing the reactivity of the radical cations of carcinogenic PAH. The strategy of this work is to react PAH radical cations with nucleophiles that are volatile and serve as models for DNA bases. Gas-phase reactivity of PAH will be evaluated in terms of adduct formation and the structure of reaction products. Once the PAH gas-phase reactivity is established, the possibility that gas-phase reactivity correlates with biological activity can be assessed. Molecular orbital calculations will also be used to investigate the theoretical charge localization of PAH radical cations. Theoretical sites of charge localization will then be compared with sites of adduct formation between the PAH and DNA fragments to investigate further the inherent reactivity of PAH radical cations.