Triphenylamine-Based Ordered Mesoporous Polymer as a Metal-Free Photocatalyst for Oxidation of Thiols to Disulfide

Abstract

Disulfides are widely present in biologically active natural products and pharmaceuticals, and they also have a wide range of applications in life sciences. The visible light-induced oxidative coupling of two thiols is one of the most efficient, atomically economical and green method for the preparation of symmetric disulfides. However, the photocatalysts used in these reactions (metal complexes, small organic molecules and inorganic semiconductors, etc.) are facing problems such as expensive, poor photostability, limited visible-light absorption and photocorrosion. Thus, it is still highly desirable to develop efficient heterogeneous photocatalysts that are free of precious metals, inexpensive, stable and recyclable, to decrease the processing costs in large-scale synthesis. Herein, a triphenylamine-based ordered mesoporous polymers (TPA-MPs) as a metal-free photocatalyst for oxidation of thiols to disulfide was reported. This protocol provides a facile means for the rapid synthesis of a series of disulfides at room temperature under air atmosphere. TPA-MPs can be easily recovered with good retention of photocatalytic activity and reused at least six times. This approach is operationally simple, mild, green, and scalable, providing a facile and efficient access to disulfides. Keywords disulfides; photoredox catalysis; heterogeneous catalysis; ordered mesoporous polymer 有机二硫化物是生物领域中普遍存在的结构单元, 是蛋白质结构形成的关键因素, 可以作为一个独特的反 应片段参与调节多种生化反应过程 [1] . 二硫化物还广泛 存在于活性天然产物及药物分子中, 此类活性物质的生 物活性通常取决于蛋白质中二硫键的交换反应 [2][3] . 硫 醇的氧化偶联是最直接的制备对称二硫化物的方法 [4] .