Photochemical and photophysical properties of tetracarboxylic acid phthalocyanines from glycolic and lactic acids in homogeneous and micro heterogeneous media

Glycolic acid and lactic acid substituted zinc phthalocyanines were studied concerning their photophysical and photochemical properties in eight organic solvents (homogeneous medium) and in aqueous media with the presence of CTAB and PVP 360 surfactants. Solvent effects were investigated according to several physical solvent parameters, including studies that used more than one parameter at a time, such as the E_T(30) scale and the Lippet-Mataga equation. Computational studies were realized and was found in good agreement with experimental data indicating J-type dimers' formation through hydrogen bonds, which may not affect the spectroscopic properties. Fluorescence lifetimes were recorded using a time-correlated single-photon counting setup (TCSPC) technique. The direct method (analyzing the phosphorescence decay curves of singlet oxygen at 1270 nm) was employed to study singlet oxygen quantum yields. Phthalocyanine macrocycle with lactic acid substituent showed better solvation arrangement than the glycolic derivative, which can be explained based on the presence of the methyl group bonded to the chain. The water solvation of Pc's in the presence of cationic surfactant (CTAB) and biocompatible polymer PVP 360 increses the importance of this study for appliance in photodynamic therapy (PDT).

Synthesis and photophysical properties of silicon(IV) tetrapyrazinoporphyrazines axially substituted with ethylene glycol chains as potential photosensitizer

Photodynamic therapy involves administration of a tumor-localizing photosensitizer, which may require metabolic conversion, followed by activation of the photosensitizer with light of a specific wavelength. In this paper, we report the design and synthesis of silicon(IV) tetrapyrazinoporphyrazines derived from 5,9,9-trimethyl-5,6,7,8-tetrahydro-5,8-methanoquinoxaline-2,3-dicarbonitrile. The HO –( CH 2 CH 2 O )n– CH 3 groups were introduced at axial positions to give a specific functionality. In particular, poly(ethylene glycol) groups were expected to increase water solubility without changing the λmax.