Monodentate Coordination of 4,4′‐Bipyridine Leading to a Supramolecular Network – Synthesis and Crystal Structure of [H2bpp][{Cu(Hbpy)2}{α‐HP2W18O62}]·4H2O

The new supramolecular compound H₂bpp]{Cu(Hbpy)₂}{α‐HP₂W₁₈O₆₂}]·4H₂O ( 1 ) (bpy = 4,4′‐bipyridine, bpp = 1,3‐bis(4‐pyridyl)propane) was synthesized hydrothermally and characterized byelemental analysis, IR spectroscopy, thermogravimetric analysis and single‐crystal X‐ray diffraction. In compound 1 , the cationic fragment Cu(Hbpy)₂]⁺ connects to the Dawson anion through a coordinating Cu←O bond, and the copper atom is coordinated by another polyoxoanion through a weak covalent bond with a Cu1–O26 distance of 2.879(2) Å, forming a polymeric chain. The bpy ligand in Cu(Hbpy)₂]⁺ adopts a monodentate coordination mode, the other nitrogen atom of the bpy ligand is protonated. The protonated Hbpy⁺ acts as hydrogen‐bond donor and constructs a two‐dimensional double‐sheet supramolecular network involving the one‐dimensional chains through the hydrogen bonds. The H₂bpp²⁺ ion connects twoα‐HP₂W₁₈O₆₂^6– clusters from two supramolecular networks through hydrogen bonds and creates a three‐dimensional supramolecular architecture. The thermal decomposition of 1 happens over a wide temperature range (450–800 °C), which indicates that it might include complicated oxidation–reduction processes.