Non-covalent interactions between halopyridine substrates and catalytically inert building blocks, namely zinc(II)-porphyrins and zinc(II)-salphens, influence the catalytic outcome of Suzuki-Miyaura and Mizoroki-Heck palladium-catalysed cross-coupling reactions. The weak Zn⋅⋅⋅N interactions between halopyridine substrates and zinc(II)-containing porphyrins and salphens, respectively, were studied by a combination of H NMR spectroscopy, UV/Vis studies, Job-Plot analysis and, in some cases, X-ray diffraction studies. Additionally, the former studies revealed unique supramolecular polymeric and dimeric rearrangements in the solid state featuring weak Br⋅⋅⋅N (halogen bonding), C-H⋅⋅⋅π, Br⋅⋅⋅π and π⋅⋅⋅π interactions. The reactivity of halopyridine substrates in homogeneous palladium-catalysed cross-coupling reactions was found to correlate with the binding strength between the zinc(II)-containing scaffolds and the corresponding halopyridine. Such observation is explained by the unfavourable formation of inactive over-coordinated halopyridine⋅⋅⋅palladium species. The presented approach is particularly appealing for those cases in which substrates and/or products deactivate (or partially poison) a transition-metal catalyst.

Weak Zn⋅⋅⋅N interactions have been exploited in homogeneous palladium catalysis. The selective binding between pyridine‐containing compounds and zinc‐containing scaffolds (porphyrin or salphen) prevents undesired catalyst inhibition, thus increasing the activity of the palladium‐phosphane catalyst. The picture illustrates how a magician uses the “Zn⋅⋅⋅N weak interactions” trick to increase the performance of the palladium catalyst inside an Erlenmeyer flask under the watchful eye of a bunny. More information can be found in the Full Paper by R. Gramage‐Doria et al. on page 5033 ff.