A Mechanochemically Active Metal‐Organic Framework (MOF) Based on Cu‐Bis‐NHC‐Linkers: Synthesis and Mechano‐Catalytic Activation
Kshitij Sanjay Shinde, Philipp Michael, D. Fuhrmann, Wolfgang H. Binder
Abstract
Abstract Porous coordination polymers, more commonly known as metal‐organic frameworks (MOFs), are constructed from metal ions and organic linkers which form a robust network‐like structure similar to very dense polymeric networks. In this work the mechanochemical activation of a MOF is reported, based on the previous results on the mechanochemical activation of latent Cu(I)‐based N ‐heterocyclic carbenes (NHCs) embedded covalently in various polymers. A mechanochemically triggered copper‐catalyzed azide‐alkyne cycloaddition (CuAAC) is achieved using an NHC‐MOF, constructed from 1,3‐bis(4‐carboxyphenyl)imidazolium chloride as organic linker. A Cu(I) bis(NHC) is embedded into the MOF analogous to ([Zn 4 O{Cu( L ) 2 } 2 ]) using the organic bis‐NHC ligand, in turn generating a largely amorphous MOF. On activation by ultrasound, the MOF containing 4.66% of Cu shows mechanochemical activation to obtain Cu(I), subsequently triggering a CuAAC with conversions up to 26.5% as monitored by the reaction of benzylazide and phenylacetylene to yield 1‐benzyl‐4‐phenyl‐1 H ‐1,2,3‐triazole over a period of 20 sonication cycles. With this knowledge in solution, there are prospects to transfer this mechanochemical activity into polymer networks with embedded MOFs to detect stress in hybrid materials.