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 ([Zn4O{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‐1H‐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.

Mechanochemical Activation In article 2200207, Wolfgang H. Binder and co‐workers demonstrate mechanochemical activation of a Cu‐metalorganic framework (MOF), in turn triggering CuAAC of a model reaction system. Activation of the MOF generates free coordination‐sites to generate spatial proximity between the azide/alkyne and thus inducing the “click”‐reaction.

The incorporation of functional groups into unsaturated polyolefine-polymers often represent a challenging task. Based on the known cyclopropanation of double bonds with diazoesters in the presence of metal-catalysts of low molecular weight compounds, we in this article develop an approach to decorate the polymer backbone of poly(diene)s with ester as well as carboxylic groups via cyclopropanation. Therefore, predominantly cis-1,4-poly(isoprene)s are converted with ethyl or tert-butyl diazoacetate using copper(I) N-heterocyclic carbene (NHC) catalysts, while focusing on the technically relevant cyclohexane as solvent. The application of commercially available NHC-Cu(I) catalysts results in modification degrees of 4-5%, while an increased solvent polarity, like dichloromethane, results in up to 17% modification. The resulting esters were further converted to the corresponding free carboxylic groups by deprotection using trifluoroacetic acid. Thus, an introduction of functional groups along the polymer backbone with a wide variety of application, like ionic interaction or hydrogen bonding motifs, was successfully demonstrated. Its potential for upscaling makes this approach feasible for an application in large-scale production processes, such as for manufacturing of modified synthetic rubbers.