A new rare-earth metal acylpyrazolonate containing the Zundel ion H5O2+stabilized by strong hydrogen bonding

A new luminescent europium derivative [H5O2][Eu(L)4] characterized by high thermal stability, ionic in acetone and ethanol solution, contains the Zundel cations H5O2+ stabilized by strong hydrogen bonding with the N atoms of the anionic heterocyclic ligand L.