Modified Dipicolinic Acid Ligands for Sensitization of Europium(III) Luminescence

Citations Over TimeTop 10% of 2006 papers

Abstract

The effect of substitution at the 4 and 3,5 positions in the pyridine ring of europium(III) pyridine-2,6-dicarboxylate complexes has been investigated with particular emphasis on sensitization of the Eu3+ ion. Sensitization of the Eu3+ 615-nm emission was achieved through excitation of the ligands in which the 4 substituent was -H, -OH, and -Cl and the 3,5 position was -H. In these cases, the ligand-to-Eu3+ ratio was confirmed as being 3:1. The sensitization was found to increase following substitution of the 4 position in the order Cl > H > OH. This is attributed to energy transfer occurring from the ligands into different Eu3+ intra-atomic energy levels, with spin selection rules governing the efficiency of this process. The Eu3+ luminescence lifetime was measured and found to vary from 1.16 to 2.90 ms depending on the excitation energy, ligand, and solvent. For the case of the 3,5-dibromo-4-hydroxy derivative, no sensitization was observed and a ligand-to-Eu3+ ratio of 1:1 was found. The solubility of these complexes in water and their long emission lifetime make them attractive for use as probes in biological systems.

Related Papers

• → Fluorescent Properties of 8-Substituted BODIPY Dyes: Influence of Solvent Effects(2015)37 cited
• → Synthesis of 1-Substituted and 1-Unsubstituted 4-Sulfonamid0-1H-pyrazol-5(2H)-ones(1996)9 cited
• → Photoreaction of 2-morpholinoacrylonitrile with substituted 1-acetonaphthones. Part II(2001)8 cited
• → ChemInform Abstract: Toward the Synthesis of Caraphenol C (VI): Substituent Effect on the Nazarov Cyclization of 2‐Arylchalcones.(2008)2 cited
• → ChemInform Abstract: Substituent Effects on η2‐Coordinated Arene Complexes of Pentaammineosmium(II).(1988)