Solvent-dependent 4^4 square grid and 6^4.8^2 NbO frameworks formed by Cu(Pyac)2(bis[3-(4-pyridyl)pentane-2,4-dionato] copper(II))

The title compound crystallizes from anhydrous solvents in a simple square-grid topology, but when water is present, crystals form with an unusual interpenetrated 3D NbO topology whose pores contain hydrogen-bonded solvent molecules.