info:eu-repo/semantics/article
Application of metal complexes as biomimetic catalysts on glycerol oxidation
Fecha
2018-11Registro en:
Parodi, Adrián Rodrigo; Merlo, Carolina; Córdoba, Agostina; Palopoli, Claudia Marcela; Ferreyra, Joaquín; et al.; Application of metal complexes as biomimetic catalysts on glycerol oxidation; Elsevier; Molecular Catalysis; 11-2018; 1-12
2468-8231
CONICET Digital
CONICET
Autor
Parodi, Adrián Rodrigo
Merlo, Carolina
Córdoba, Agostina
Palopoli, Claudia Marcela
Ferreyra, Joaquín
Signorella, Sandra Rosanna
Ferreira, María Luján
Magario, Ivana
Resumen
Two biomimetic complexes were evaluated as catalysts in the H2O2 mediated oxidation of glycerol, namely a peroxidase mimetic Fe(III) protoporphyrin complex (hematin) and the superoxide-dismutase mimetic complex of Mn(III) with 1,3-bis(5-sulphonatesalycilidenamino) propane (MnL−). Catalysis was targeted to glyceraldehyde since antimicrobial power was proved for it. Glyceraldehyde evolved at a higher rate than the uncatalyzed reaction only with hematin acid treated solutions and kinetics were typical of a radical mechanism. Nonetheless, glycerol conversions were low. H2O2 bleached hematin and the immobilization on a porous matrix could not prevent this. Meanwhile, the catalatic activity of hematin was high but its peroxidatic activity was inhibited at pH > 8. Thus, the coordination of hematin compound I to H2O2 over glycerol may be the preferred route with the accumulation of peroxy radicals, able to degrade the porphyrinic ring -with probable iron releasing- but also contributing to glycerol oxidation. On the other hand, a prompt decay with time of the catalatic and peroxidatic activities of MnL− was observed, which was improved by the addition of dimethylsulfoxide (DMSO), dimethylformamide (DMF) or acetone to the basic buffer system. Finally, EPR spectroscopy of MnL− supported the hypothesis of the formation of an inactive bis-oxo-bridged Mn(IV)Mn(IV) dimer upon addition of H2O2.