Journal of Photochemistry and Photobiology A: Chemistry ( IF 4.1 ) Pub Date : 2022-06-28 , DOI: 10.1016/j.jphotochem.2022.114111
Vlasta Brezová , Zuzana Barbieriková , Michal Zalibera , Karol Lušpai , Andrea Tholtová , Dana Dvoranová
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Cyclic nitrone spin trap 5,5-dimethyl-1-pyrroline N-oxide (DMPO) and its derivatives were applied in an EPR study of paramagnetic intermediates generated by in situ photoexcitation of TiO2 nanoparticles dispersed in acetonitrile with fluorinated ions. The UVA irradiation of deoxygenated acetonitrile titania suspensions containing the spin traps in the presence of fluoride or tetrafluoroborate, and Ag(I) or Cu(II) as photoelectron acceptors, resulted in the generation of the corresponding fluorine spin-adducts with well-resolved EPR signals. The EPR spectra of β-fluorine spin-adducts of the DMPO analogs, featuring ethoxycarbonyl (EMPO), diethoxyphosphoryl (DEPMPO), or diisopropoxyphosphoryl (DIPPMPO) groups at position 5 of the pyrroline ring, are reported for the first time. The reaction mechanisms leading to the β-fluorine spin-adduct formation in the given photocatalytic system are discussed.
中文翻译:
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二氧化钛介导的乙腈中硝酮自旋阱的光致氟化(EPR 研究)
环状硝酮自旋阱 5,5-二甲基-1-吡咯啉N-氧化物 (DMPO) 及其衍生物应用于TiO 2原位光激发产生的顺磁性中间体的 EPR 研究含氟离子的纳米颗粒分散在乙腈中。在存在氟化物或四氟硼酸盐以及 Ag(I) 或 Cu(II) 作为光电子受体的情况下,对含有自旋陷阱的脱氧乙腈二氧化钛悬浮液进行 UVA 照射,导致产生具有良好分辨的 EPR 的相应氟自旋加合物信号。首次报道了 DMPO 类似物的 β-氟自旋加合物的 EPR 光谱,其特征在于吡咯啉环 5 位上的乙氧基羰基 (EMPO)、二乙氧基磷酰基 (DEPMPO) 或二异丙氧基磷酰基 (DIPPMPO) 基团。讨论了在给定的光催化体系中导致β-氟自旋加合物形成的反应机制。