Morphology and radical reactions of Cu(II) and Co(II) sulfonated phthalocyanines covalently linked to poly(ethyleneamide)

Abstract

The tetrasulfonated CuII(tspc)4-, tspc = 4,4´,4",4"´-phthalocyaninetetrasulfonate, and the trisulfonated CoII(trspc)3-, trspc = n,n´,n"-phthalocyanine- trisulfonate and n, n’ and n” indicate the sulfonated positions of the various isomers, were covalently linked to a polyethyleneimine, Mn ~ 10000 and Mw ~ 25000, backbone. A fraction of the amine groups in a strand was converted to CuIIpc(-SO3)3(-SO2N<)– or CoIIpc(-SO3)2(-SO2N<)- pendants and the remaining were acetylated. Strands of the polymers, poly(K3CuIItspc) and poly(K2CoIItrspc), formed spherical bundles with diameters ~ 1000 nm for poly(K3CuIItspc) and ~ 100 nm for poly(K2CoIItrspc). The stability of the bundles is metal dependent. Poly(K2CoIItrspc) forms the most stable bundles with respect to hydrolytic and redox reactions. ESR and optical spectroscopies as well as reactions of the pendants with pulse radiolytically generated radicals, namely e-sol, C•H2OH, (CH3)2COHC•H2, CO2•-, N3• and SO4•-, revealed a distribution of pendants between isolated and aggregated forms in a bundle. The reduction of the Cu(II) to Cu(I) in aqueous solutions of the poly(K3CuIItspc) was associated with pendants present in a mostly hydrophobic environment. Unstable phthalocyanine pendants with CoIII-Carbon bonds are formed when CoIIpc(-SO3)2(-SO2N<)- reacted with C-centered radicals, (CH3)2COHC•H2 and C•H2OH. The species with CoIII-Carbon bonds were precursors in the formation of CoIpc(-SO3)2(-SO2N<)- pendants. The redox reactions of the pendants in these polymers are compared with those of the K4CuIItspc and K3CoIItrspc.