Synthesis of tuneable amphiphilic-modified polyketone polymers, their complexes with 5,10,15,20-tetrakis-(4-sulfonatophenyl)porphyrin, and their role in the photooxidation of 1,3,5-triphenylformazan confined in polymeric nanoparticles

A series of amphiphilic polymers bearing aliphatic secondary amines and hydroxyl groups have been synthesized showing different hydrophilic/hydrophobic balance. The synthesis is performed through the Paal-Knorr modification of a polyketone comprising both ethylene and propylene comonomers with N-(2-hydroxyethyl)ethylenediamine. The values of dicarbonyl conversion achieved were 19, 35, 51, and 63%, which allowed controlling the amphiphilia of the polymers: a lower carbonyl conversion degree implies a higher hydrophobia. On the other hand, photodegradation studies of a model nanosized pollutant pigment comprised of 1,3,5-triphenylformazan nanoparticles stabilized by poly(sodium 4-styrenesulfonate) have been performed in the absence and in the presence of the photocatalyst 5,10,15,20-tetrakis-(4-sulfonatophenyl)porphyrin, showing no catalytic action, since electrostatic repulsion minimize molecular contacts between the reactants. However, the synthesized polymers allow overcoming this problem. Due to their amphiphila, the polymers showing dicarbonyl conversion values of 35, 51, and 63% form complexes with the porphyrin and stabilize its non-self-aggregated tetraanionic form in water from basic pH up to pH 1.74, 1.82, and 2.76, respectively, the differences related with the polymeric relative hydrophilic/hydrophobic balance. Only the amphiphilic polymer showing a conversion degree of 35% acts as an adequate vehicle for the dye to photocatalyze the oxidation of 1,3,5-triphenylformazan confined in the nanoparticles, highlighting the potential of the Paal-Knorr modification of polyketones to achieve a fine Cunning of polymeric properties to obtain a specific functionality: the positive charge of the complex and the high hydrophobia of the tuned polymer allow, respectively, attractive long-range electrostatic interactions with the nanoparticles and diffusion of the reactants into the nanoparticle hydrophobic environment.