Porphyrins Embedded in Translucent Polymeric Substrates: Fluorescence Preservation and Molecular Docking Studies

This research describes the functionalization of polymer-matrix-trapping porphyrins, considering that the transcendental properties of meso-substituted porphyrins, such as optical and chemical stability, combined with the strength of the polymers, can produce photoactive advanced polymeric networks. Polystyrene (PS) and O,O´-bis-(2-aminopropyl)-polyethyleneglycol-300 (2NH₂peg300, APEG), or their combination, were used to confine the meso-substituted porphyrin species 5,10,15,20-tetrakis(4'-carboxy-1,1'-biphenyl-4-yl)porphyrin and 5,10,15,20-tetrakis((pyridin-4-yl)phenyl)porphyrin. The samples were characterized by Fourier-transform infrared (FTIR), X-ray diffraction (XRD), ultraviolet-visible (UV-Vis) and fluorescence spectroscopies. The absorption and emission properties of the materials were compared to those of their respective porphyrin solutions. The fluorescence was preserved in the obtained composite through a mixture of polymers, PS, and APEG, yielding translucent polymeric networks. Moreover, analysis of individual polymeric assemblies by molecular docking was performed to support the understanding of the experimental findings. This analysis corroborates that the stronger the estimated binding energies, the stronger the interactions that occur between porphyrin and the polymer via non-polar covalent bonds.