CAU-10-PDC metal-organic framework readily absorbs Br₂ vapors forming a new mild brominating agent. Rietveld refinement is used to determine the positions of the trapped bromine species in the MOF pore. Activated aromatics bromination is shown. The MOF reversible bonding nature with Br₂ and the side-forming HBr makes the MOF a useful and reusable container for Br₂ and allows trapping HBr .

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 are 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 have 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 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.