ZrO core cluster with formula unit [ZrO(OH)(OH)(CHCOO)(SO)]·HO obtained under mild conditions.

During attempts to synthesize zirconium-based MOFs, we have obtained a new crystal structure of the cluster with ZrO core and formula unit [ZrO(OH)(OH)(CHCOO)(SO)]·HO. Unlike other systems, mild conditions were employed in this case; no strong acids or hydrothermal conditions were required. The molecular assembly in the crystal is characterized by strong O-H⋯O hydrogen bonds connecting neighboring molecules, allowing the formation of a three-dimensional maze of tunnels with HO molecules stabilizing the framework. Noteworthy, at 100 °C, the strong ZrO core and the O-H⋯O hydrogen bonds help form a system where the molecular cluster is conserved, but the long-range order is lost. FT-IR, Raman, TGA, DSC, and X-ray diffraction techniques were used to characterize the title compound.