Ma Yuanyuan, Peng Haiyue, Liu Jianing, Wang Yonghui, Hao Xiuli, Feng Xiaojia, Khan Shifa Ullah, Tan Huaqiao, Li Yangguang
Key Laboratory of Polyoxometalate Science of Ministry of Education Faculty of Chemistry , Northeast Normal University , Changchun 130024 , China.
School of Chemical and Biological Engineering , Taiyuan University of Science and Technology , Taiyuan 030021 , China.
Inorg Chem. 2018 Apr 2;57(7):4109-4116. doi: 10.1021/acs.inorgchem.8b00282. Epub 2018 Mar 13.
Polyoxometalates (POMs) show considerable catalytic performance toward the selective oxidation of alkenes to aldehydes, which is commercially valuable for the production of pharmaceuticals, dyes, perfumes, and fine chemicals. However, the low specific surface area of POMs as heterogeneous catalysts and poor recyclability as homogeneous catalysts have hindered their wide application. Dispersing POMs into metal-organic frameworks (MOFs) for the construction of POM-based MOFs (POMOFs) suggests a promising strategy to realize the homogeneity of heterogeneous catalysis. Herein, we report two new POMOFs with chemical formulas of [Co(BBTZ)][HBWO]·10HO (1) and [Co(HO)(BBTZ)][BWO]·NO·4HO (2) (BBTZ = 1,4-bis(1,2,4-triazol-1-ylmethyl)benzene) for the selective oxidation of alkenes to aldehydes. Compound 1 possesses a non-interpenetrated three-dimensional (3D) cds-type open framework with a 3D channel system. Compound 2 displays a 3D polyrotaxane framework with one-dimensional channels along the [100] direction. In the selective oxidation of styrene into benzaldehyde, compound 1 can achieve a 100% conversion in 4 h with 96% selectivity toward benzaldehyde, which is superior to that of compound 2. A series of control experiments reveal that the co-role of [BWO] and Co active center as well as a more open framework feature co-promote the catalytic property of the POMOFs in this case. This work may suggest a new option for the development of POMOF catalysts in the selective oxidation of alkenes.
多金属氧酸盐（POMs）对烯烃选择性氧化为醛表现出可观的催化性能，这在药物、染料、香料和精细化学品的生产中具有商业价值。然而，POMs作为多相催化剂时比表面积低，作为均相催化剂时可回收性差，这阻碍了它们的广泛应用。将POMs分散到金属有机框架（MOFs）中以构建基于POM的MOFs（POMOFs），为实现多相催化的均相性提供了一种有前景的策略。在此，我们报道了两种新的POMOFs，其化学式分别为[Co(BBTZ)][HBWO]·10HO（1）和[Co(HO)(BBTZ)][BWO]·NO·4HO（2）（BBTZ = 1,4 - 双（1,2,4 - 三唑 - 1 - 基甲基）苯），用于烯烃选择性氧化为醛。化合物1具有非互穿的三维（3D）cds型开放框架和3D通道系统。化合物2展示了沿[100]方向具有一维通道的3D聚轮烷框架。在苯乙烯选择性氧化为苯甲醛的反应中，化合物1在4小时内可实现100%的转化率，对苯甲醛的选择性为96%，优于化合物2。一系列对照实验表明，在这种情况下，[BWO]和Co活性中心的协同作用以及更开放的框架结构共同促进了POMOFs的催化性能。这项工作可能为开发用于烯烃选择性氧化的POMOF催化剂提供了一种新选择。
