Synthesis, structure and luminescence properties of samarium (III) and dysprosium (III) complexes with a new tridentate organic ligand

A novel organic ligand, 6-diphenylamine carbonyl 2-pyridine carboxylic acid (HDPAP), and the corresponding lanthanide complexes, tris(6-diphenylamine carbonyl 2-pyridine carboxylato) samarium (III) (Sm-DPAP) and tris(6-diphenylamine carbonyl 2-pyridine carboxylato) dysprosium (III) (Dy-DPAP) have been designed and synthesized. The crystal structures and photoluminescence of Sm- DPAP and Dy-DPAP have been studied. The results showed that the lanthanide complexes have electroneutral structures, and the solid samarium complex emits characteristic red fluorescence of Sm (III) ions at room temperature while the dysprosium complex emits the DPAP ligand phosphorescence. The lowest triplet level of DPAP ligand was calculated from the phosphorescence spectrum of Gd-DPAP in N,Ndimethyl formamide dilute solution determined at 77 K, and the energy transfer mechanisms in the lanthanide complexes were discussed. q 2003 Elsevier B.V. All rights reserved