Metal‐4,4′‐azobis(3,5‐dimethyl‐1H‐pyrazole) Complexes with Seven‐ and Nine‐membered Hydrogen‐bonded Rings Originating from the Pyrrolic NH Function

The metal complexes Cu(NO₃)₂(H₂O)₂(H₂azbpz)₂] · 2H₂O ( 1 ) and Ni(H₂O)₄(H₂azbpz)₂](NO₃)₂ · 2H₂O ( 2 ) of 4,4′‐azobis(3,5‐dimethyl‐1H‐pyrazole) (H₂azbpz) incorporate the bipyrazole as a monodentate ligand and are associated into supramolecular architectures by hydrogen bonds and azo‐pz π interactions in the solid state. In 1 a cis configuration is integrated and the NH function adjacent to the metal‐coordinating nitrogen atom gives rise to a seven‐membered anion‐assisted hydrogen‐bonded ring around the central metal atom bringing the NH function in endo‐position to the azo‐bridge. The interplay of hydrogen‐bonds and dimeric azo‐pz π interactions in 1 forms one‐dimensional supramolecular chains, which are further interconnected by a heterodromic D_2h symmetric tetrameric water ring. In 2 a trans form of H₂azbpz is mono‐coordinated and the synergy of hydrogen‐bonded rings around the central metal atom and continuous azo‐pz π interactions form a two‐dimensional supramolecular network structure. The supramolecular packings of 1 and 2 is further underpinned by the analysis of their Hirshfeld surface areas.