A mixed‐valence copper(I/II) coordination polymer directed with a bifunctional soft‐hard pyrazolate‐carboxylate ligand

A mixed-valent, one-dimensional Cu(I/II) coordination polymer with the formula [Cu-II{Cu-3(I)(Hmpba)(mpba)(2)}DMF] . similar to 3DMF was obtained with the bifunctional ligand 4-(3,5-dimethyl-1H-pyrazol-4-yl)benzoic acid (H(2)mpba) in N,N-dimethylformamide (DMF) via solvothermal reaction. The compound exhibits a trinuclear {Cu-3(I)(Hmpba)(mpba)(2)}(2-) metallo-linker with the softer Cu(I) linearly-coordinated by the softer pyrazolate nitrogen donor atom. This metallo-linker connects the harder Cu(II) ions through its harder carboxylate groups into a chain structure. Two Cu(II) ions form a paddlewheel unit and are, thus, surrounded by four carboxylate groups. Cu(II) is five-coordinated with a terminal DMF ligand. Parallel chains are connected into supramolecular layers through the common R-2(2)(8) hydrogen-bond motif of the singly-deprotonated carboxyl groups of the Hmpba ligand. These layers are further organized by Cu(I)-Cu(I) interactions into a 3D supramolecular array.