Synthesis and Luminescence Properties of Lanthanide Complexes of a Novel Polyaminopolycarboxylate Ligand

Abstract

A novel polyaminopolycarboxylate ligand with many coordination sites, N,N,N 1 ,N 1 ,N 2 ,N 2 -[( 2,4,6-tri(aminomethyl)-pyridine]hexakis(acetic acid) (TPHA), was designed and synthesized and its lanthanide complexes Na6Tb2(TPHA)Cl6· 14H2O, Na6Eu2(TPHA)Cl6·8H2O, Na6Gd2(TPHA)Cl6·11H2O and Na6Sm2(TPHA)Cl6·9H2O were successfully prepared. The ligand and the complexes were characterized by elemental analysis, IR, mass, NMR and TG-DTA. The TG-DTA studies indicated that the complexes had a high thermal stability, whose initial decomposition temperature was over 270 o C. The luminescence properties of the complexes in solid state were investigated and the results suggested that Tb 3+ and Eu 3+ ions could be sensitized efficiently by the ligand, especially the Tb(III) complex displayed a very strong luminescence intensity (> 10000) and only displayed characteristic metal-centered luminescence. Also, the correlative comparison between the structure of ligand and luminescence properties showed how the number of the coordination atoms of ligand can be a prominent factor in the effectiveness of ligand-to-metal energy transfer.

Synthesis, luminescence properties of a novel aromatic carboxylic acid (L) and corresponding Eu(III) and Tb(III) compounds as well as the binding characteristics of L with bovine serum albumin (BSA)

“…The structures of the ligands are very similar and the primary difference between them is that the novel ligand has more coordination sites. Thus, it can be explained that the increase of the number of the coordination atoms resulted in the energy transfer from ligand to metal ion more effective, and it is also in agreement with our former study [15]. Interestingly, we find that the luminescence intensity of the complexes reported in this paper is much stronger than that of our former reported complexes [15].…”

“…Thus, it can be explained that the increase of the number of the coordination atoms resulted in the energy transfer from ligand to metal ion more effective, and it is also in agreement with our former study [15]. Interestingly, we find that the luminescence intensity of the complexes reported in this paper is much stronger than that of our former reported complexes [15]. It may be attributed to that the ligand L has a pyridine ring as well as two pyrazole rings, while the former ligand has only a pyridine ring.…”

Designing Near‐Infrared and Visible Light Emitters by Postsynthetic Modification of Ln+3–IRMOF‐3

“…Energy‐dispersive X‐ray spectroscopy analysis gives a 2:1 Cl/Ln molar ratio and reveals the presence of three DMSO molecules. The FTIR evidence (Figures 2, a and S15) is clear and, upon complexation, (1) the carbonyl band shifts from $\tilde {\nu}$ = 1714 (free carbonyl) to 1623 cm –1 , (2) the bands at 1006 and 960 cm –1 are due to S–O and C–S stretching, respectively, of a coordinated DMSO molecule22 and (3) the bands at $\tilde {\nu}$ = 568 and 412 cm –1 are attributed to Ln–N and Ln–O stretching vibrations, respectively 23…”