Synthesis, Crystal Structure, and Modelling of a New Tetramer Complex of Europium

Abstract

A new compound with the formula [Eu4(ETA)9(OH)3(H2O)3)], where ETA is ethyl 4,4,4-trifluoroacetoacetate, has been synthesized and investigated by photoluminescence spectroscopy. The compound was characterized by means of chemical analysis, vibrational (IR), UV-vis absorption, and luminescence spectroscopies, and X-ray crystallography. The crystal structure of the [Eu4(ETA)9(OH)3(H2O)3)] complex in the solid state, determined by X-ray diffraction analysis, revealed that it crystallizes in the triclinic crystal system, space group P, with four crystallographically independent europium centers. From these structural data, the ground-state geometry of the tetramer has been calculated by using the Sparkle/AM1 model. The emission spectrum shows the characteristic transitions of the Eu3+ ion. The features displayed by the5D0-->7F0 transition in the emission spectrum are consistent with the Eu3+ ion occupying four different sites in chemical environments of low symmetries, in agreement with the X-ray data and the optimized geometry obtained from the Sparkle/AM1 model. These structural results have allowed the theoretical calculation of 4f-4f intensity parameters, including the forced electric dipole and dynamic coupling mechanisms as well as ligand singlet and triplet states, in good agreement with experiment.

Hydrothermal synthesis, crystal structure and luminescence of two new 2D coordination polymers [Ln(IN)(CO3)(H2O)] (LnLa, Eu) constructed by interesting flat lanthanide carbonate layers

“…The coordination environment of the Eu(III) ion is asymmetry and have no inversion center, which can be confirmed by the appearance of the emission 5 D 0 → 7 F 0 (symmetry-forbidden) at 580 nm [24][25][26]. The intensity of 5 D 0 → 7 F 2 transition (electric dipole) is higher than the 5 D 0 → 7 F 1 transition (magnetic dipole), and the ratio of about 3.46 for I( 5 D 0 → 7 F 2 )/I( 5 D 0 → 7 F 1 ) further confirms the view above [27]. Interestingly, the very strong characteristic emission spectrum associated with the Eu(III) ion is observed, while the IN − based emission is absent.…”

Two New Series of Potentially Triboluminescent Lanthanide(III) β‐Diketonate Complexes

“…An X‐ray diffraction study revealed the presence of the nonanuclear mixed‐valent Eu III /Eu II cluster Eu 9 (μ 4 ‐OH) 2 (μ 3 ‐OH) 8 (bnac) 16 ( 5 ). A number of related penta‐, octa‐, and nonanuclear europium hydroxo cluster complexes containing β‐diketonate ligands have already been reported in the recent literature . The experimentally determined magnetic moments are μ/μ B = 3.36 ( 4 ) and also 3.36 for each Eu 3+ ‐ion in the nonanuclear compound 5 .…”

Hydrothermal Synthesis, Structural Determination, and Properties of a New Family of Mononuclear Lanthanide Complexes with Pyridines Bearing More Flexible Pendant-Arm Carboxylate Substituents

“…The 5 D 0 → 7 F 2 transition and 5 D 0 → 7 F 1 transition are electronic dipole transition and magnetic dipole, respectively, and the intensity of the former is stronger than that of the latter, which indicates that the coordination environment of the Eu(III) ion is asymmetric. [21] With excitation at 320 nm, the emission lines of complex 6 are respectively assigned to the 5 D 4 → 7 F 6 (489 nm) and 5 D 4 → 7 F 5 (545 nm) transitions of Tb(III) labeled in Figure 3c, and the fluorescence intensity at 545 nm is stronger. For complex 7, two characteristic bands excited at 311 nm can be seen in the emission spectra peaking at 482 nm and 574 nm, which are respectively attributed to transitions of 4 F 9/2 → 6 H 15/2 and 4 F 9/2 → 6 H 13/2 recorded in Figure 3d.…”