A Mild Recyclable MOF-based Brominating Agent Br2@CAU-10-PDC with HBr Trapping Function.

Abstract

A wide range of brominating agents and heterogeneous brominating systems indicates a demand in the field of organic compounds bromination. A new mild and recyclable metal-organic framework (MOF) - based brominating agent, Br2@CAU-10-PDC (CAU = Christian-Albrechts-University), has been synthesized and successfully applied to the bromination of activated aromatics, such as phenols, amines and amides. Infrared and Raman spectroscopy, as well as powder X-ray diffraction were used to characterize the obtained composite. Rietveld refinement of the composite structure has also been performed, as a result, the positions of bromine species associated with pyridine nitrogen and specific interactions with each other has been determined. The agent synthesis and recycling steps are straightforward. The recyclability of the agent is achieved due to the reversible nature of the linker bonding with Br2 and HBr. This unique feature makes the composite the first, to our knowledge, brominating agent that readily traps HBr without losing its properties. The presented composite can become a valuable addition to the group of mild, reusable and multifunctional brominating agents.