A Mixed Covalent–Supramolecular Interpenetrated Copper–Phosphonate Network

A novel copper‐based coordination network Cu(1,4‐DPB)(H 2 NBP) was synthesized via a hydrothermal process using 1,4‐di(pyridin‐4‐yl)benzene (1,4‐DPB) and naphthalene‐1,4‐diylbis(hydrogenphosphonate) (H 2 NBP 2– ) as organic linkers. Single‐crystal structure analysis shows that the Cu(II) center exhibits a square‐planar coordination and is surrounded by three oxygen atoms from different hydrogenphosphonate groups as well as a nitrogen atom from the 1,4‐DPB linker. The structure is based on zigzag‐shaped Cu–bisphosphonate double strands that are connected by the organic linkers to form a two‐dimensional coordination network. These layers are organized via hydrogen bonds into a three‐dimensional, two‐fold interpenetrated hydrogen‐bonded framework as a mixed covalent–supramolecular copper–phosphonate network. Thermogravimetric studies reveal a higher thermal stability of the network compared to the free linkers. Photophysical measurements demonstrate complete quenching of the free linker luminescence upon metal coordination in the network.