Anionic lanthanide complexes with 3-methyl-1-phenyl-4-formylpyrazole-5-one and hydroxonium as counter ion

AbstractA series of [H3O]+[LnL4]−·nH2O complexes (n=1–3, Ln=Nd, (1), Sm (2), Eu (3), Tb (4); HL=3-methyl-1-phenyl-4-formylpyrazole-5-one) were synthesized and characterized. The structures of the SmIII and EuIII complexes were investigated by X-ray diffraction. The isostructutal crystalls 2 and 3 consist the tetrakis [LnL4]− anions which are linked by H-bonding with the hydroxonium counter-ion and water molecules. The lanthanide ion is situated in the center of distorted tetragonal antiprism formed by eight oxygen atoms of 4-formyl-5-hydroxypyrazolonate anions. The TbIII and SmIII complexes show strong luminescence in solid state, whereas the EuIII and NdIII complexes show low luminescence activity