Based on the pioneering work of Lin Wenbins group over the past ten years, metal organic framework (MOF) photochemistry has shown great potential in the fields of photodynamic therapy, solar energy utilization and conversion, and photocatalysis, and has received extensive attention from scientists. Through reasonable ligand design, it is easy to introduce metal molecular photosensitizers into the MOF framework to achieve high-efficiency photocatalysis. Organic dye molecules with good photochemical properties are cheap and easy to obtain, but due to their large size and low symmetry, it is difficult to be introduced into a three-dimensional MOF. Metal organic ultra-thin layer material (MOL) is a two-dimensional analog of three-dimensional MOF. They not only retain the advantages of MOF structure order, adjustability and good stability, but also their special monolayer configuration can provide fully accessible active sites. Professor Lin Wenbins team took the lead in researching and developing two-dimensional metal organic ultra-thin layer materials (MOL) (Angew. Chem. Int. Ed., 2016, 55, 4962; Angew. Chem. Int. Ed., 2017, 56, 12102) Chem. Soc., 2019, 141, 15767; J. Am. Chem. Soc., 2020, 142, 1746; Angew. Chem. Int . Ed., 2021, 60, 3115).


Figure 1. Design of the first column of metal organic catalysts loaded with organic dyes
Based on the above research, the metal-organic ultra-thin layer material may be used as a good two-dimensional carrier to introduce the photosensitive center of organic dyes. Not only that, its two-dimensional configuration also provides the possibility of catalyzing the functionalization of large-scale and complex molecules. Professor Lin Wenbins team developed the first series of bifunctional MOL catalysts containing organic dyes and metallic iron active centers. The team first synthesized Hf-MOL with Hf6-secondary building unit and TPY ligand. Through post-modification synthesis, eosin Y organic dye and Fe(OTf)2 center were introduced into Hf6-secondary building unit and TPY ligand, respectively. A series of characterizations proved its monolayer configuration, photophysical properties and Fe center structure. Experiments have shown that Hf-EY-Fe can efficiently catalyze the trifluoromethyl bifunctionalization of olefins and the later functionalization of large-sized drug molecules. In the three-dimensional MOF structure, these biologically active molecules are large in size (1.4-2.2). nm) Difficult to pass through its pores. Mechanism studies have proved that the separation of EY dye and Fe sites but close to each other (~1.0 nm) inhibits the deactivation of the catalytic center, and promotes the transfer of electrons and free radical intermediates, resulting in excellent synergistic catalytic performance (up to 1840 Conversions). These research results reflect the versatility of MOL catalyst and its potential application prospects in drug synthesis.


Figure 2. Synthesis and characterization of the catalyst
Compared with metal organic framework (MOF) materials, metal organic ultra-thin layer materials (MOL) exhibit the advantages of high dispersion, easy modification and easy access. It can be expected that they have broader application potential in the fields of organic collaborative catalysis and drug molecule development.


Figure 3. Difunctionalization of olefins catalyzed by Hf-EY-Fe
This work was recently published in the Journal of the American Chemical Society. Quan Yang Jian and Shi Wenjie from the Department of Chemistry at the University of Chicago are the co-first authors of the article. This article is Professor Lin Wenbins 100th academic paper published in JACS. We congratulate him on his achievements and pay tribute to his outstanding contributions in the field of metal organic materials! Paper link:
DOI: 10.1021/jacs.1c01083