An international team of scientists has tethered palladium to a metal–organic framework (MOF) support using thiol groups normally associated with catalyst poisoning. In doing so, the metal centre becomes neither too soluble nor too crowded, but is instead just right for lossless catalysis.
The modified MOF catalyses a coupling reaction between a boronic acid and 4-bromo-2-fluorobenzonitrile
Heterogeneous catalysts, where metal catalysts are supported on an insoluble structure, are easier to recover than soluble homogeneous catalysts. Leaching of the metal catalyst from a support into solution is however a central problem in heterogeneous catalysis. Metals lost to the supernatant can be costly, either in catalyst replacement or additional purification and recovery processes. In drug synthesis there are strict limits on residual metals in active pharmaceutical ingredients. Palladium levels must, for example, be less than 10 ppm for oral intake, and an order of magnitude lower for parenteral exposure.
Read the full article in Chemistry World»
Read the original journal article in ChemComm – it’s free to access until 13th May 2015:
Tackling poison and leach: catalysis by dangling thiol–palladium functions within a porous metal–organic solid
Bo Gui, Ka-Kit Yee, Yan-Lung Wong, Shek-Man Yiu, Matthias Zeller, Cheng Wang and Zhengta Xu
Chem. Commun., 2015,51, 6917-6920
DOI: 10.1039/C5CC00140D, Communication
