Dissociative electron attachment to some spinochromes: Fragment anion formation.

Resonance attachment of low-energy (0–14 eV) electrons to a series of natural polyphenolic naphtho-quinones (so-called spinochromes) derived from sea urchins is studied by means of dissociative electronattachment (DEA) spectroscopy. The experimental findings are interpreted using quantum-chemical cal-culations of the empty level structure to predict the energies of negative ion resonant states as well asthe thermodynamic energy thresholds for formation of fragments by DEA. A variety of fragment speciesis found to be formed at very low energies of incident electrons, thus modeling reductive conditionsin living cells near the pathways of cellular electron transfer. In particular, the temporary molecularanions of the compounds under investigation dissociate efficiently through elimination of neutral Hatoms or diatomic hydrogen molecules (in analogy with previous findings in flavonoids), this processbeing energetically possible owing to the presence of multiple hydroxyl groups usually associated withradical scavenging activity. A likely correlation between dehydrogenation of spinochromes stimulated byelectron attachment and their well-documented antioxidant protective properties is briefly discussed.