Syntheses, Structures, and Luminescent and Magnetic Properties of Novel Three-Dimensional Lanthanide Complexes with 1,3,5-Benzenetriacetate

Abstract

Five novel lanthanide complexes with the formulas [Nd(bta)(H2O)2·4.35H2O] n (1), [Sm(bta)(H2O)2·4.5H2O] n (2), [Eu(bta)(H2O)·1.48H2O] n (3), [Tb(bta)(H2O)·1.31H2O] n (4), and [Yb(bta)(H2O)·H2O] n (5) (H3bta = 1,3,5-benzenetriacetic acid) have been prepared by using the corresponding lanthanide salt and H3bta. The results of an X-ray crystallographic analysis revealed that all the complexes have three-dimensional channel-like structures, in which the bta3- ligands adopt different coordination modes: monodentate and μ2-η2:η1-bridging coordination modes in 1, 2, and 5 and μ2-η1:η1-bridging and μ2-η2:η1-bridging coordination modes in 3 and 4, respectively. Complexes 1 and 2, as well as 3 and 4, are isostructural, respectively, in which all the LnIII (Ln = Nd, Sm, Eu, and Tb) atoms are nine-coordinated, while the YbIII atoms in complex 5 are eight-coordinated. Both complexes 3 and 4 showed strong luminescence upon excitation, and their luminescence decay curves fit well with single exponential decays of which the lifetime is 0.45 ms for 3 and 1.0 ms for 4. The magnetic properties of the complexes were investigated in the temperature range of 1.8−300 K.

Three‐Dimensional Open‐Frameworks Based on LnIIIIons and Open‐/Closed‐Shell PTM Ligands: Synthesis, Structure, Luminescence, and Magnetic Properties

“…The first one is responsible for the green luminescence observed in 4'. [65,66] Photoemission/-excitation spectra for compound 2' are shown in Figure 6. The low-resolution PL spectrum obtained at 298 K was improved by working at 10 K (Figure 6a) F n metal transitions (for n = 0-5, respectively).…”

“…This is supported by numerous examples of Ln-based coordination polymers magnetically characterized in the literature. [66,72,73] Despite the predictability of the magnetic behavior, such data for compounds 1', 3', 4', and 5' were of interest to investigate the nature of the {Ln-radical} interaction in 1, 3, 4, and 5, but also to obtain more precise information concerning {Gd-Gd} interactions in 3, and help to confirm the occurrence of {radical-radical} interactions in 2. Since coordination polymers 1'-5' and 1-5 are isostructural, the ligand field effect is the same whether PTMTC 3À or aH-PTMTC…”

Syntheses, structures, and magnetic properties of new rare earth coordination polymers constructed by 1,3,5-benzenetriacetic acid

“…4, respectively, in which χ M is the corrected molar magnetic susceptibility per [Gd 2 ] or [Dy 2 ] unit. As for 1, the orbital contribution of Gd(III) ion, with a half-filled 4f shell, to magnetic moment is almost entirely quenched, thus an isolated Gd(III) ion has an 8 S 7/2 ground state, which prevents the use of a spin-only Hamiltonian for isotropic exchange [21,27,28]. The product of χ M T is practically constant over the entire temperature range, and the observed value is 16.06 emu K mol −1 at room temperature which corresponds to two isolated Gd(III) ions (the calculated value of χ M T for two Gd free ions is 15.75 emu K mol −1 , g = 2), and the plot of χ −1 M vs. T over the whole temperature range obeys the Curie-Weiss law with C = 16.07 emu mol −1 K and θ = − 0.79 K. All these indicate that the magnetic coupling interaction between the nearest Gd(III) ions in 1 is very weak.…”

“…The polymers of transition and alkaline-earth metals with the flexible multicarboxylate ligands 1,3,5-benzenetriacetic acid (H 3 bta) have also been investigated recently [18,19]. Considering the high coordination numbers and the variable geometry of the rare earth metals and the diversity of the binding modes of the flexible carboxylate groups, we selected H 3 bta as ligand and hope to construct novel rare earth coordination polymers with fascinating structures and/or interesting properties [20,21]. Herein we describe the syntheses, structural characterizations and magnetic properties of three rare earth complexes [Gd(bta) ( …”

Synthesis, crystal structure and magnetic property of a two‐dimensional herringbone‐like network with praseodymium(III) nitrate and 1‐bromo‐ 3,5‐bis(imidazol‐1‐ylmethyl)benzene (bib)

“…The Pr-N and Pr-O bond distances are similar to those observed in the reported Pr(III) complexes with nitrogen donors 24 and oxygen donors. 14 The coordination geometry of each Pr(III) atom is distorted bicapped square antiprism, which is a common coordination geometry for the 10-coordinated lanthanide ions. 25,26 It is clear that in the title complex, each bib acts as a bidentate-bridging ligand to connect two Pr(III) atoms using its two flexible arms, as shown in Fig.…”