山西师大张献明课题组：三苯胺基MOF中光生载流子迁移路径的调控及光催化氧化硫醇制备二硫醚-上海善施科技

Concise Report

Immobilizing Triphenylamine with Photoredox Inert Sr2+ Forming Sr-MOF with Controlled Electron Migration for Photocatalytic Oxidation of Thiols to Disulfides

Ying-Xia Wang, Fang Zheng, Dong-Xia Song, Bao-Yue Niu, Lu-Qian Deng, and Xian-Ming Zhang*

The photocatalytic oxidative coupling of thiols is one of the most popular methods to synthesize the disulfides. Triphenylamine and its derivatives (TPAs) are promising for the above reaction, but suffer from the easy polymerization and difficult separation. To overcome these obstacles while controlling the photogenerated electrons transfer directly to target substrates, herein, we constructed one TPA-based metal-organic framework (MOF), (Me2NH2)[Sr(TCBPA)]·DMA·3H2O (1), by direct self-assembly of tris(4′-carboxybiphenyl)amine (H3TCBPA) and photoredox inert strontium ion (Sr2+). DFT calculations revealed that the valence band maximum (VBM) and the conduction band minimum (CBM) are mainly located on TCBPA3‒, successfully inhibiting the undesirable electron migration to metal nodes. Experimental results indicated that 1displays superior performance than homogeneous H3TCBPA, which may result from the abundant π···π and C—H···π interactions between the well-arranged TCBPA3‒ and the build-in electric field between the anionic framework and the Me2NH2+. This work highlights that immobilizing TPAs into MOFs is one promising approach to designing heterogeneous photocatalysts for the synthesis of disulfides by oxidative coupling of thiols.

三苯胺基MOF中光生载流子迁移路径的调控及光催化氧化硫醇制备二硫醚

二硫醚是一类结构中含有S-S键的化合物，在生物、医药、农药等领域具有广泛应用。硫醇的光催化氧化是制备二硫醚化合物的一种常用方法。其中，三苯胺及其衍生物等有机染料是该方法中常用的一类光催化剂，但存在均相催化易失活、难分离，异相催化更倾向于充当光敏中心而非催化中心的缺点。

图1. 三苯胺与氧化还原惰性的Sr2+配位实现光生载流子的可控迁移

针对这一问题，山西师范大学的张献明教授、王映霞副教授等人通过将三(4´-羧基联苯)胺(H3TCBPA)与光氧化还原惰性的锶离子自组装，得到了具有可控光生载流子迁移路径的与框架材料(Me2NH2)[Sr(TCBPA)]，并将其应用于硫醇的光催化氧化制备二硫醚。DFT计算表明，该框架材料中价带和导带均来自三(4´-羧基联苯)胺的贡献，TCBPA3–作为光催化剂直接将光生电子传递给分子氧，生成的空穴能将硫醇高效率、高选择性地氧化为二硫醚。实验结果表明，由于该材料中具有丰富的π···π和C-H···π相互作用以及客体二甲基胺阳离子和框架阴离子间的内建电场，该材料表现出比母体三(4´-羧基联苯)胺更优异的催化性能。该项研究成果对有机合成中异相光催化剂的设计与合成具有重要指导意义。

上述研究结果作为封面文章发表于Chin. J. Chem. 2024, 42, 1093—1099. DOI: 10.1002/cjoc.202300677。该项工作得到了国家自然科学基金委、山西省“1331”工程、山西省回国留学人员科研资助项目、山西师范大学的资助。

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