On the redox reactions occurring between radicals and AlIII(phthalocyaninate) pendants inside pockets of micelle-like aggregates of an AlIII(phthalocyaninate) - decorated polymer

G.T. RUIZ; A.G. LAPPIN; G. FERRAUDI

JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY

JOHN WILEY & SONS INC

Lugar: New York ; Año: 2012 p. 2507 - 2515

0887-624X

The mechanisms of the redox reactions between a polymer containing Al(III) sulfonated phthalocyanine pendants, (AlIII(└NHS(O2)trspc )2-)2, and radicals were investigated in this work using the pulse radiolysis technique and photochemical methods. Oxidizing radicals, OH•, HCO3•, (CH3)2COHCH2• and N3•, and reducing radicals, eaq-, CO2•- and (CH3)2C•OH, respectively accept or donate one electron forming pendent phthalocyanine radicals, AlIII(└NHS(O2)trspc •)- or 3-,  in such processes. The kinetics of the redox processes is consistent with a mechanism where the pendants react with radicals formed inside aggregates of 5 to 6 polymer strands. Electron donating radicals, i.e., CO2•- and (CH3)2C•OH, produce one-electron reduced phthalocyanine pendants that, even thought they were stable under anaerobic conditions, donated charge to a Pt catalyst. While the polymer was regenerated in the Pt catalyzed processes, 2-propanol and CO2 were respectively reduced to propane and CO. The reaction of SO3•- radicals with the polymer stood in contrast with the reactions of the radicals mentioned above. A first step of the mechanism, the coordination of the SO3•- radical to the Al(III), was followed by the formation of a SO3•- - phthalocyanine ligand adduct. The decay of the SO3•- - phthalocyanine ligand adduct in a ~102 ms time domain regenerates the polymer and it was attributed to the dimerization/disproportionation of SO3•- radicals escaping from the aggregates of polymer.