Tian Long, Song Xiaonan, Liu Yi, Zhang Churu, Shi Lan, Chen Qinglin, Deng Yanyan, Cui Weigang, Shan Shaoyun, Hu Tianding
Faculty of Chemical Engineering, Kunming University of Science and Technology, Kunming 650500, PR China.
Faculty of Chemical Engineering, Kunming University of Science and Technology, Kunming 650500, PR China.
J Colloid Interface Sci. 2024 May 15;662:263-275. doi: 10.1016/j.jcis.2024.02.067. Epub 2024 Feb 9.
Defect-engineered metal-organic frameworks (DEMOFs) are emerging advanced materials. The construction of DEMOFs is of great significance; however, DEMOF-based catalysis remains unexplored. (E)-vinylboronates, an important building block for asymmetric synthesis, can be synthesized via the hydroboration of alkynes. However, the lack of high-performance catalysts considerably hinders their synthesis. Herein, a series of DEHKUST-1 (HKUST = Hong Kong University of Science and Technology) (Da-f) catalysts with missing occupation of linkers at Cu nodes were designed by partially replacing benzene-1,3,5-tricarboxylate (HBTC) with defective connectors of pyridine-3,5-dicarboxylate (PYDC) to efficiently promote the hydroboration of alkynes. Results showed that the Dd containing 0.8 doping ratio of PYDC exhibited remarkable catalytic activity than the defect-free HKUST-1. This originated from the improved accessibility for reactants towards the Lewis acid active Cu sites of DEHKUST-1 due to the presence of plenty of rooms next to the Cu sites and enhanced coordination ability in such 'defective' HKUST-1. Dd had high selectivity (>99 %) and yield (>96 %) for (E)-vinylboronates and extensive functional group compatibility for terminal alkynes. Density functional theory (DFT) calculations were performed to elucidate the mechanism of hydroboration. Compared with that of defect-free HKUST-1, the low energy barrier of DEHKUST-1 can be attributed to the lower coordination number of Cu sites and enhanced accessibility of Cu active sites towards reagents.
缺陷工程金属有机框架（DEMOFs）是新兴的先进材料。DEMOFs的构建具有重要意义；然而，基于DEMOFs的催化作用仍未得到探索。（E）-乙烯基硼酸酯是不对称合成的重要构建单元，可通过炔烃的硼氢化反应合成。然而，缺乏高性能催化剂严重阻碍了它们的合成。在此，通过用吡啶-3,5-二羧酸（PYDC）的缺陷连接体部分取代苯-1,3,5-三羧酸（HBTC），设计了一系列在铜节点处缺少连接体占据的DEHKUST-1（HKUST = 香港科技大学）（Da-f）催化剂，以有效促进炔烃的硼氢化反应。结果表明，含有0.8掺杂比例PYDC的Dd表现出比无缺陷的HKUST-1更显著的催化活性。这源于由于铜位点旁边存在大量空间以及这种“缺陷”HKUST-1中配位能力增强，反应物对DEHKUST-1的路易斯酸活性铜位点的可及性提高。Dd对（E）-乙烯基硼酸酯具有高选择性（>99%）和高收率（>96%），并且对末端炔烃具有广泛的官能团兼容性。进行了密度泛函理论（DFT）计算以阐明硼氢化反应的机理。与无缺陷的HKUST-1相比，DEHKUST-1的低能垒可归因于铜位点的配位数较低以及铜活性位点对试剂的可及性增强。
