A new family of dimeric lanthanide (III) complexes: Synthesis, structures and photophysical property

A new family of lanthanide complexes with the general formula {[Ln(nphth)(Hnphth)(H2O)3·H2O]2}n (Ln = Pr, Eu, Gd, Tb, Dy, 1–5 and H2nphth = 3-nitrophthalic acid) have been synthesized under hydrothermal condition and four of them have been characterized by single-crystal X-ray diffraction and spectroscopy. These compounds are isostructural and the lanthanide ions are all nine coordinated and europium complex emits characteristic red fluorescence of Eu3+ ions at room temperature while other three lanthanide complexes exhibit the particular emission ascribed H2nphth ligand, which suggest that the different energy transfer process takes place.