Sulfanyl Porphyrazines with Morpholinylethyl Periphery—Synthesis, Electrochemistry, and Photocatalytic Studies after Deposition on Titanium(IV) Oxide P25 Nanoparticles

The syntheses, spectral UV–Vis, NMR, and electrochemical as well as photocatalytic properties of novel magnesium(II) and zinc(II) symmetrical sulfanyl porphyrazines with 2-(morpholin-4-yl)ethylsulfanyl peripheral substituents are presented. Both porphyrazine derivatives were synthesized in cyclotetramerization reactions and subsequently embedded on the surface of commercially available P25 titanium(IV) oxide nanoparticles. The obtained macrocyclic compounds were broadly characterized by ESI MS spectrometry, 1D and 2D NMR techniques, UV–Vis spectroscopy, and subjected to electrochemical studies. Both hybrid materials, consisting of porphyrazine derivatives embedded on the titanium(IV) oxide nanoparticles’ surface, were characterized in terms of particle size and distribution. Next, they were subjected to photocatalytic studies with 1,3-diphenylisobenzofuran, a known singlet oxygen quencher. The applicability of the obtained hybrid material consisting of titanium(IV) oxide P25 nanoparticles and magnesium(II) porphyrazine derivative was assessed in photocatalytic studies with selected active pharmaceutical ingredients, such as diclofenac sodium salt and ibuprofen.

Development of UV absorbers for sun protective fabrics

The textiles for protection against harmful UV radiation have become the focus of great interest in the present time. However, not all apparel is well-protected against UV light. Therefore, the application and improvement of UV absorbers for sun protective fabrics is being sought. In this study, various benzophenone UV absorbers containing benzotoriazolyl groups were prepared, and the Ultraviolet Protection Factors (UPF) and improving the light fastness of dyes was examined. A series of hydroxybenzophenones bearing a built-in benzotriazole moiety showed a very high UPF, and played a very important role in the improvement of light fastness of dyes. It was found that 2,2’,4,4’-tetrahydroxy-5,5’-dibenzotriazolylbenzophenonesulfonic acid or the methyl derivative shows very high UPF, and plays an important role in improving the light fastness of dyes. It was further demonstrated that the combined use of these UV absorbers and singlet oxygen quencher, NTS (Nickel p-toluenesulfonate), can be applied as effective stabilizers against the photofading of dyes.

The role of reactive oxygen species in Staphylococcus aureus photoinactivation by methylene blue

Methylene blue (MB) has been shown to photoinduce the direct inactivation of Gram-positive bacteria Staphylococcus aureus (S. aureus) in water. We have investigated the mechanism of S. aureus photoinactivation conducting firstly sodium azide (reactive ion N3−), as a good physical singlet oxygen quencher, then the amino acids tryptophan (Trp), as a non-specific singlet oxygen quencher and the mannitol, as an hydroxyl free radical scavenger. Inactivation of MB photosensitization is the antioxidants type dependent. When the bacteria was treated with MB (20 μM) under light during 10 min of exposure, it was found that survival fraction had decreased dramatically to about 31.27±5.39%. The presence of sodium azide and Trp failed to shown any protection from the MB photodynamic activity. In the presence of mannitol, S. aureus could be protected, reaching a protection level of about 27%. It is possible that the photodynamic activity of MB occurred in part, via a Type I mechanism in which •OH was produced. The interactions between MB and S. aureus were studied spectrophotometrically. This demonstrated that a metachromatic reaction took place between MB and S. aureus bacteria. Furthermore, S. aureus bacteria induced additional dimerization of MB.