Self-assembly of polyoxometalate-based metal organic frameworks based on octamolybdates and copper-organic units: from [Cu.sup.II], [Cu.sup.I,II] to [Cu.sup.I] via changing organic amine

Six polyoxometalate (POM)-based hybrid materials are designed and prepared based on octamolybdate building blocks and copper-organic units at different pH values under hydrothermal conditions. The successful isolation of these species has provided clue for the supramolecular isomerism in POMs-based MOFs, which has helped in understanding the structure-property relationship of POMs-based MOFs.