A cyclic water octamer in a binuclear copper(II) complex: synthesis, crystal structure, and properties

A cyclic octameric water cluster is trapped in a 3-D supramolecular architecture [Cu2(H2O)2(bpca)2L] 8H2O, where bpca = bis(2-pyridylcarbonyl)amide and L = sebacic acid. The striking feature of the octameric cluster is that each water donates one hydrogen to adjacent waters to form a circular water ring in a (O–H O–H )4 connecting fashion, with the same orientations of OH bonds in the ring. Thermogravimetric and magnetic properties are also reported.