10.1039/b005834n
The research focuses on the azidohydroperoxidation of pinenes, specifically α- and β-pinene, to produce 2-azidohydroperoxides with excellent regio- and diastereoselectivity. The purpose of this study is to explore the stereoselectivity pattern of these reactions and achieve the first X-ray crystal structure determination of a 2-azidohydroperoxide. The reactions are initiated by photoinduced electron transfer (PET) from azide anions in the presence of oxygen and an organic dye as a photosensitizer, leading to the formation of difunctionalized products via either trapping of cyclic peroxidic intermediates or intermediary α-azido carbon radicals by azide anions or oxygen. The researchers used visible light irradiation alongside sodium azide (NaN?), oxygen, and rhodamine B as a PET-sensitizer in methanol-water mixtures. They achieved optimal yields and selectivities for α-pinene and observed notable reactivity for β-pinene as well.
10.1039/c3ce42654h
The study examines the adsorption and photocatalytic performance of bismuth oxyiodide (BiOI) for the degradation of three dyes: methyl orange (MO), Rhodamine B (RhB), and methylene blue (MB). The adsorption performance of BiOI was found to vary depending on the dye, with the order of adsorption efficiency being MO < RhB < MB. This trend was attributed to the electrostatic interactions between the positively charged RhB and MB dyes and the negatively charged BiOI surface, while MO, being negatively charged, interacted less favorably. Under UV and visible light irradiation, the photocatalytic degradation of MO followed the order BiOI < Ag–BiOI < Ti–BiOI, indicating that Ti-doping enhanced the photocatalytic activity. For RhB, BiOI alone was more effective under UV light, but Ag and Ti-doped BiOI showed better performance under visible light, suggesting a dye-sensitized mechanism where the dye absorbs light and transfers energy to the catalyst. Methylene blue (MB), despite being efficiently adsorbed, showed poor photocatalytic degradation under both UV and visible light, indicating that its removal was primarily through adsorption rather than photocatalysis. The study also identified superoxide radicals (?O2 -) and holes (h+) as the active species responsible for dye degradation under visible light, with no significant contribution from hydroxyl radicals (?OH). These findings highlight the complex interplay between adsorption and photocatalytic mechanisms in BiOI and its doped variants for dye degradation.
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