Aqueous-Phase Synthesis of Cyclic Trinuclear Cluster-Based Metal–Organic Frameworks
Kun Wu, Wei Zhao, Ling Huang, Wenting Zeng, Qiang Zhu, Haobo Wang, Qinhong Wang, Xiansong Shi, He Li, Weigang Lu, Guo‐Hong Ning, Dan Zhao, Dan Li
Abstract
The synthesis of metal–organic frameworks (MOFs) often involves high-boiling-point organic solvents, which can have extensive environmental impact and limit their large-scale applications. Here, we present a one-pot aqueous-phase approach for the rapid preparation of 33 trinuclear-copper-cluster-based MOFs ( 1 to 33 ) with different pyrazoles under ultrasonic irradiation. To address the water-solubility challenge of organic linkers, we employ aromatic amines/aldehydes and pyrazole aldehydes/amines to in situ generate imine-based pyrazoles. This linker dismantling strategy enables the formation of low-concentration pyrazoles, which are essential for the assembly of trinuclear-copper-cluster-based MOFs in the aqueous phase. The use of preassembled trinuclear gold complexes instead of aromatic amines affords an Au–Cu-based MOF ( 34 ) of alternating gold and copper clusters, a rare example of MOFs with mixed yet precise arrangement of metal compositions. Additionally, the direct addition of pyruvic acid to the reaction mixture results in the facile synthesis of a carboxylic-acid-functionalized MOF ( 35 ), eliminating the need for preinstallation or postmodification steps in traditional MOF synthesis. Furthermore, we demonstrate 11-AA as an efficient photocatalyst for cross-dehydrogenative coupling (CDC) reactions, exploiting the synergetic effect of substrate activation on the copper sites and subsequent coupling initiated by the photosensitive organic linkers. This work offers a simple solution for making MOFs with minimal environmental impact; it also opens up possibilities for developing multifunctional MOFs for diverse applications.