What is it about?
The sulfate anion is one of the most important ligands for transition-metal compounds such as polyoxometalates, metal sulfates, polynuclear complexes. In contrast, transition-metal complexes having a protonated sulfate anion ligand are still rare, because this type of anion more often acts as a counter-anion than as a ligand. However, it is reported that a protonated sulfate group in metal oxide catalysts plays an important role in the catalytic activity. Therefore, a transition-metal complex having a protonated sulfate anion ligand is expected to be an appropriate model compound to understand the active site of sulfated metal oxide catalysts at the molecular level. In this paper, we have successfully revealed the crystal structure of a new dinuclear vanadium complex having a unique protonated sulfate anion as its ligand.