On the redox reactions of radicals with AlIII(phthalocyaninate) pendants covalently bonded to poly(ethyleneamide). Mechanistic alterations when radicals are formed inside pockets of micelle-like polymer aggregates

Abstract The mechanisms of the redox reactions between a polymer containing Al(III) sulfonated phthalocyanine pendants, (Al III ( ⌊ NHS(O 2 )trspc) 2− ) 2 , and radicals have been investigated in this work. Pulse radiolysis and photochemical methods were used for these studies. Oxidizing radicals, OH • , HCO 3 • , (CH 3 ) 2 COHCH 2 • , and N 3 • , as well as reducing radicals, e aq − , CO 2 •− , and (CH 3 ) 2 C • OH, respectively accept or donate one electron forming pendent phthalocyanine radicals, Al III ( ⌊ NHS(O 2 )trspc • ) − or 3− . The kinetics of the redox processes is consistent with a mechanism where the pendants react with radicals formed inside aggregates of five to six polymer strands. Electron donating radicals, that is, CO 2 •− and (CH 3 ) 2 C • OH, produce one‐electron reduced phthalocyanine pendants that, even though 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 CO 2 were respectively reduced to propane and CO. The reaction of SO 3 •− 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 SO 3 •− radical to the Al(III), was subsequently followed by the formation of a SO 3 •− ‐ phthalocyanine ligand adduct. The decay of the SO 3 •− ‐ phthalocyanine ligand adduct in a ∼10 2 ms time domain regenerates the polymer, and it was attributed to the dimerization/disproportionation of SO 3 •− radicals escaping from the aggregates of polymer. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012