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 I 3 (Hmpba)(mpba) 2 }DMF] ⋅ ∼3DMF was obtained with the bifunctional ligand 4‐(3,5‐dimethyl‐1 H ‐pyrazol‐4‐yl)benzoic acid (H 2 mpba) in N,N ‐dimethylformamide (DMF) via solvothermal reaction. The compound exhibits a trinuclear {Cu I 3 (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.