Proprietăți fotofizice și fotochimice a ftalocianinei de Zn conjugate cu nanoparticule de metal nobil (AuNPs și AgNPs) [Articol]

Abstract

In this study, zinc phthalocyanines (ZnPcs) substituted with tetracarboxy groups were synthesized and characterized using UV–VIS spectroscopy, fluorescence spectroscopy, NMR, and mass spectrometry. The photophysical properties depend on the peripheral substituents and the presence of noble metal nanoparticles. The UV–VIS spectra of ZnPcs 15–19 showed Soret bands at 348–352 nm and Q bands at 615–683 nm, typical of nanostructured phthalocyanines. The emission spectra, upon excitation at 616 nm, displayed two main bands at 688–692 nm and 757–759 nm, assigned to the Q(x)(0–0) and Q(x)(0–1) transitions. The fluorescence quantum yields (ΦF) varied significantly: ZnPc 16 exhibited the highest ΦF, while ZnPc 19 showed reduced values in the increased presence of AgNPs. Samples 16–18 presented higher yields than the reference sample. Fluorescence lifetimes indicated energy transfer to the triplet state for some compounds. The solvent effect study revealed a decrease in fluorescence intensity with increasing water content in DMSO, suggesting aggregation and quenching. The results demonstrate the influence of peripheral substitution and the surrounding medium on the photophysical behavior of zinc phthalocyanines.