Synthetic eumelanin produced using 5,6-dihydroxyindole-2-carboxylic acid as precursor and H2O2/horseradish peroxidase as oxidative reagent, in form of dry powder, has been investigated under photoexcitation by TR-EPR spectroscopy. The formation of spin polarized radical pairs from triplet excited states of melanin has been obsd. both in absence and in presence of oxygen and has been followed as a function of the temp. in the range 140-290 K. The triplet mechanism explains the obsd. polarization pattern in net emission. In the presence of oxygen new radical pairs are formed by interaction of melanin with mol. oxygen.
Time-resolved EPR investigation of oxygen and temperature effects on synthetic eumelanin / Conti, F.; Panzella, Lucia; Napolitano, Alessandra; D'Ischia, Marco; Toffoletti, A.. - In: SPECTROSCOPY. - ISSN 0712-4813. - STAMPA. - 24:3,4(2010), pp. 289-295. [10.3233/SPE-2010-0430]
Time-resolved EPR investigation of oxygen and temperature effects on synthetic eumelanin
PANZELLA, LUCIA;NAPOLITANO, ALESSANDRA;D'ISCHIA, MARCO;
2010
Abstract
Synthetic eumelanin produced using 5,6-dihydroxyindole-2-carboxylic acid as precursor and H2O2/horseradish peroxidase as oxidative reagent, in form of dry powder, has been investigated under photoexcitation by TR-EPR spectroscopy. The formation of spin polarized radical pairs from triplet excited states of melanin has been obsd. both in absence and in presence of oxygen and has been followed as a function of the temp. in the range 140-290 K. The triplet mechanism explains the obsd. polarization pattern in net emission. In the presence of oxygen new radical pairs are formed by interaction of melanin with mol. oxygen.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
