Odd And Even Rare Earth Complexes Of Aromatic Carboxylic Acid, Crystal Structure And Luminescence Properties

Ten ternary complexes of Tb(III), fourteen quaternary complexes of Tb(III) doped with Y(III) and four quaternary complexes of Tb(III) doped with Gd(III) have been synthesized. In these complexes, eight aromatic carboxylic acids were as the first ligand, and 1,10-phenanthroline (or 2,2'-bipyridine) as the second ligand. The compositions of these complexes were confirmed by elemental analysis (C, H, N) and EDTA titration for rare earth.The ternary complexes of Tb(III) were characterized by means of IR, UV, TG-DTG and SEM methods. In these complexes, the Tb(III) ions bond to the oxygen atoms of carboxylate and the nitrogen atoms of neutral ligands. The complexes with phen coligand are more stable than those with bipy coligand. The structures of two ternary complexes Tb(o-MOBA)₃ phen·H₂O (1) and Tb(m-MOBA)₃ phen·C₂H₅OH (2) have been determined using X-ray diffraction. Both complexes exist as binuclear molecules, and crystallize in triclinic, space group P1. Relevant crystallographic parameters are as follows: 1, a = 11.4300(19) A, b = 12.752(2) A, c = 13.147(2) A, α = 66.717(3)°, β = 83.435(3)°, γ = 70.488(3)°; 2, a =11.7540(15) A, b =12.0794(15) A, c =14.0423(18) A, α =106.791 (2)°, ,β = 99.249(3)°, γ = 104.405(2)°.The luminescence spectra of the Tb(III) complexes show that the positions of emission peaks remain unchanged. However, the emission intensity of the complexes is different for the different ligands or different doped metal ions. The major works are as follows in this paper: (i) the best luminescent complex is chosen in each series; (ii) the influences of different doped metal ions on the luminescence of Tb(III) complexes are compared; (iii) the optimum doped proportion of the same sensitive metal ions in the complexes is concluded. These results will provide some valuable materials for the synthesis of new effective rare earth luminescent materials.