Influence of the halide and exposed facets on the visible-light photoactivity of bismuth oxyhalides for selective aerobic oxidation of primary amines
Influence of the halide and exposed facets on the visible-light photoactivity of bismuth oxyhalides for selective aerobic oxidation of primary amines
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DOI：
10.1016/j.apcatb.2017.07.050
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发表时间：
2017-12
影响因子：
22.1
通讯作者：
Aijuan Han;Hongwei Zhang;G. Chuah;S. Jaenicke
中科院分区：
文献类型：
--
作者：
Aijuan Han;Hongwei Zhang;G. Chuah;S. Jaenicke
双卤氧化合物BiOX（X = Cl，Br，I）作为光催化剂在有机合成中应用较少。在此，我们研究了它们的潜在的好氧氧化偶联苄胺到N-亚苄基苄胺，亚胺是重要的合成中间体的药物和生物活性的含氮有机化合物。研究了卤化物和暴露的晶面对光活性的影响。BiOBr表现出优异的光活性，超过了光吸收和氧化能力分别较差的BiOCl和BiOI。合成了三种不同小面的BiOBr光催化剂。由于有效的电荷分离，{001}面化的BiOBr表现出比{010}或{110}-样品更高的固有活性。然而，表面积起着重要的作用，因为反应通常发生在催化剂表面。由于它们的大得多的表面积，溶剂热合成的BiOBr微球具有{110}-主导暴露面显示出最高的光氧化活性，在室温下使用来自大气的氧气照射14 h后，具有100%的转化率和100%的N-亚苄基苄胺选择性。本工作为亚胺的合成提供了一种经济、可行、可持续的绿色工艺，并说明卤氧化铋作为光催化剂在有机合成中的巨大潜力。
Bismuth oxyhalides BiOX (X = Cl, Br, I) are seldom applied as photocatalysts in organic synthesis. Herein, we investigated their potential for the aerobic oxidative coupling of benzylamine toN-benzylidenebenzylamine, as imines are important synthetic intermediates of pharmaceuticals and biologically active nitrogen-containing organic compounds. The influence of the halide and the exposed crystal facets on the photoactivity was investigated. BiOBr showed excellent photoactivity, surpassing BiOCl and BiOI, which have poor light absorption and oxidation ability, respectively. Three differently facetted BiOBr photocatalysts were synthesized. The {001}-facetted BiOBr exhibited higher intrinsic activity than the {010}- or {110}-samples due to efficient charge separation. However, surface area plays an important role as reactions usually occur at the catalyst surface. Because of their much larger surface area, the solvothermally-synthesized BiOBr microspheres with {110}-dominant exposed facet showed the highest photooxidative activity, with 100% conversion and 100% selectivity toN-benzylidenebenzylamine after 14 h visible light irradiation at room temperature using oxygen from atmospheric air. This work provides an economical, feasible, sustainable and green process for the synthesis of imines and illustrates the great potential of bismuth oxyhalides as photocatalysts for organic synthesis.