A combined experimental and computational approach was used to investigate the spectroscopic properties of three different aniline derivatives (aniline, N,N-dimethylaniline, and N,N-diethylaniline) in aqueous solutions and at the air–ice interface in the temperature range of 243–298 K. The absorption and diffuse reflectance spectra of ice samples prepared by different techniques, such as slow or shock freezing of the aqueous solutions or vapor deposition on ice grains, exhibited unequivocal bathochromic shifts of 10–15 nm of the absorption maxima of anilines in frozen samples compared to those in liquid aqueous solutions. DFT and SCS-ADC(2) calculations showed that contaminant–contaminant and contaminant–ice interactions are responsible for these shifts. Finally, we demonstrate that irradiation of anilines in the presence of a hydrogen peroxide/O₂ system by wavelengths that overlap only with the red-shifted absorption tails of anilines in frozen samples (while having a marginal overlap with their spectra in liquid solutions) can almost exclusively trigger a photochemical oxidation process. Mechanistic and environmental considerations are discussed.

中文翻译：

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苯胺衍生物的光氧化可通过冻结其水溶液而被激活

结合实验和计算方法来研究三种不同苯胺衍生物（苯胺，N，N-二甲基苯胺和N，N-二乙基苯胺）在水溶液中以及在243-298 K的温度范围内的空气-冰界面。通过不同技术制备的冰样品的吸收和漫反射光谱，例如水溶液的缓慢或冲击冷冻或气相沉积在冰粒上，与液体水溶液相比，在冷冻样品中苯胺的吸收最大值表现出明确的红移10-15 nm。DFT和SCS-ADC（2）的计算表明，污染物-污染物和污染物-冰的相互作用是造成这些转变的原因。最后，我们证明在过氧化氢/ O ₂存在下辐照苯胺通过仅与冷冻样品中苯胺的红移吸收尾巴重叠的波长（虽然与液体溶液中的光谱略有重叠）重叠的波长系统几乎可以完全触发光化学氧化过程。讨论了机械和环境方面的考虑。