Photophysical properties of hybrid porphyrin-erythrosine B fluorophore in aqueous media and PVA films

A diaxial complex of the Sn(IV)-5,10,15,20-tetra-(4-carboxyphenyl)porphyrin with a fluorescein halogen derivative– Erythrosine B (triad “luminophore-porphyrinate-luminophore”) was synthesized. Its structure was established using NMR spectroscopy and mass spectrometry. Its luminescent properties (fluorescence spectra, quantum yield and fluorescence lifetime, as well as the ability to generate singlet oxygen) were studied. It has been established that the resulting triad has the properties of a fluorescent molecular rotor, and both fragments of the triad [porphyrinate ([Formula: see text] = 420 nm) and xanthene ([Formula: see text] = 470 nm) fragments] show high fluorescent sensitivity to local viscosity. By immobilizing the triad “luminophore-porphyrinate-luminophore” into a polymer matrix of polyvinyl alcohol (PVA), hybrid film materials were obtained. It has been shown that the fixation of the triad in the polymer matrix due to the formation of hydrogen bonds between carboxyl groups and the organic polymer does not have a significant effect on its luminescent properties. It has been established that both fragments in the triad immobilized in PVA-based polymer organic films retain their properties as fluorescent “molecular rotors” in non-aqueous media.