New dendritic porphyrins: Synthesis, spectroscopic and antibacterial evaluation

In this work, a new porphyrin-dendrimer (Pf-PPI) was synthesized, which can form complex Ag⁺ leading to a Pf-PPI-Ag⁺ stable compound. The molecular structure of the dendrimers was characterized by ¹H NMR and ¹³C NMR, FT-IR, TGA and UV–vis. The metal complexation capacity of dendritic nanostructures was evaluated using filtration followed by atomic absorption, and the binding sites were elucidated by FT-IR spectrometry and TGA analysis. The results show that the functional groups in dendrimer branches are involved in the retention rate of cations. Transient studies proved good capacity for singlet oxygen generation even in the presence of the cation, showing that both complexing and sensitizing properties are compatible with each other. The antibacterial effect of the compounds on E. coli was also evaluated. Although some dark toxicity was observed, a complete and faster bacterial inactivation was recorded under visible light irradiation, demonstrating high photodynamic efficiency of the tested compounds.