Stabilization of a new type of water octamer in the crystalline hydrate of an inorganic-organic hybrid material: Synthesis and characterization of [{Cu(phen)(H2O)2}2(Mo8O26)] · 8H2O

Abstract

A supramolecular water octamer, (H2O)8 has been crystallographically observed to be formed in the crystalline hydrate of an inorganic-organic hybrid compound [{Cu(phen)(H2O)2}2(Mo8O26)] · 8H2O (1). Compound 1 consists of an octamolybdate isopolyanion, two mono(phenanthroline)copper(II) complex cations and eight lattice water molecules per formula unit. The formation of such unusual (H2O)8 cluster is believed to be stabilized by its non-covalent O-H⋯O type hydrogen bonding interactions with the isopolyanion in the solid state. To the best of our knowledge, this is the first instance of a discrete water octamer found in a polyoxometalate-based system.