Catechol and its derivatives are model compounds used to investigate the binding dynamics and photo-induced interfacial charge transfer events between an organic molecule and TiO₂. However, the practical potential of this process has received little attention in part due to the conceived instability of these molecules on TiO₂ under light irradiation. Herein, we present a new paradigm for selective oxidation of amines into imines with atmospheric O₂ by exploring the surface complexation of catechol derivatives on TiO₂ which gives rise to visible-light-induced events of charge transfer. Our success depends on the merger of visible light photocatalysis of catechol surface-complexed TiO₂ with TEMPO catalysis. With 5 mol% of TEMPO as the co-catalyst and the catechol–TiO₂ complex (containing 0.8 mol% of catechol) as the photocatalyst, amines can be efficiently oxidized into imines with atmospheric O₂ under irradiation of blue light emitting diodes. Our work suggests that a suitable co-catalyst is the key to significantly expand the scope of visible light photocatalysis for selective chemical transformations.

中文翻译：

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将儿茶酚-TiO ₂复合光催化剂与TEMPO合并，将胺选择性好氧氧化成亚胺† ‡

邻苯二酚及其衍生物是用于研究有机分子与TiO ₂之间的结合动力学和光诱导界面电荷转移事件的模型化合物。然而，该方法的实际潜力很少受到关注，部分是由于这些分子在光照射下在TiO ₂上的不稳定性。在本文中，我们通过探索邻苯二酚衍生物在TiO ₂上的表面络合，产生可见光诱导的电荷转移事件，提出了一种将胺与大气O ₂选择性氧化为亚胺的新范例。我们的成功取决于对邻苯二酚表面络合的TiO ₂可见光光催化的合并TEMPO催化。用5 mol％的TEMPO作为助催化剂和邻苯二酚-TiO ₂络合物（包含0.8 mol％的邻苯二酚）作为光催化剂，在蓝色发光二极管的照射下，胺可以与大气O ₂有效地氧化为亚胺。我们的工作表明，合适的助催化剂是显着扩大可见光光催化范围以进行选择性化学转化的关键。