An Organodiphosphate-Containing Polyoxoniobate Ring and Its Assembly into a Three-Dimensional Framework through Hydrogen Bonding.

In this work, a novel organodiphosphate-containing inorganic-organic hybrid polyoxoniobate (PONb) ring {(POCHCHPOH)NbO} () has been achieved by a one-pot hydrothermal method. The ring is constructed from a tetragonal {NbO} motif and four {POCHCHPOH} ligands. Interestingly, can be joined together via K-HO clusters {K(HO)(OH)} to form one-dimensional chains {[K(HO)(OH)]} and further linked by {Cu(en)} (en = ethylenediamine) complexes, resulting in a three-dimensional supramolecular framework {[Cu(en)][K(HO)(OH)]}·3en·HO (). exhibits good chemical and thermal stability and has a high water vapor adsorption capacity of ≤224 cm g (22.71 mol·mol) at 298 K, outperforming most of the known polyoxometalate-based materials. Impedance measurements prove that can transfer protons with moderate conductivity. This study not only contributes to the structural diversity of organodiphosphate-containing PONbs and PONb rings but also provides a reference for the development of PONb-based materials with unique performance.