Assembly Chemistry between Lanthanide Cations and Monovacant Keggin Polyoxotungstates: Two Types of Lanthanide Substituted Phosphotungstates [{(α-PW₁₁O₃₉H)Ln(H₂O)₃}₂]⁶⁻ and [{(α-PW₁₁O₃₉)Ln(H₂O)(η²,μ-1,1)-CH₃COO}₂]¹⁰⁻

Abstract

Two 2:2 types of monolanthanide substituted polyoxometalates [{(R-PW 11 O 39 H)Ln(H 2 O) 3 } 2 ] 6-(Ln=Nd III for 1 and Gd III for 2) and [{(R-PW 11 O 39 )Ln(H 2 O)(η 2 ,μ-1,1)-CH 3 COO} 2 ] 10-(Ln=Sm III for 3, Eu III for 4, Gd III for 5, Tb III for 6, Ho III for 7 and Er III for 8) have been synthesized in aqueous solution and characterized by elemental analyses, IR spectra, UV-vis-NIR spectra, thermogravimatric analyses and single-crystal X-ray diffraction. The common structural features are that they are constructed from monovacant Keggin-type polyoxoanions [R-PW 11 O 39 ] 7and trivalent lanthanide cations. Both 1 and 2 are essentially isomorphous, and the molecular structure is built by two symmetrically related monolanthanide substituted Keggin units [R-PW 11 O 39 Ln(H 2 O) 3 ] 4linked via two Ln-O-W bridges, representing the first monovacant Keggin polyoxotungstate dimers constituted by two [R-PW 11 O 39 ] 7polyoxoanions and two lanthanide cations in polyoxometalate chemistry. 3-8 are also isostructural and display another dimeric structure constructed from two monolanthanide substituted units [(R-PW 11 O 39 )Ln(H 2 O)(η 2 ,μ-1,1)-CH 3 COO] 5bridged by two (η 2 ,μ-1,1)-acetato ligands. The photoluminescence properties of 4 and 6 were investigated at room temperature. Magnetic susceptibility measurements of 1, 3, 4, 7 and 8 between 2 and 300 K exhibit that their magnetic behaviors mainly result from the spin-orbital coupling interactions as well as weak antiferromagnetic exchange interactions within magnetic centers. The electrochemical properties of 1, 3, 4, 5, 7 and 8 were studied by means of cyclic voltammetry in aqueous solution with 0.5 M Na 2 SO 4 as supporting electrolyte.

Yttrium containing head-on complexes of silico- and germanotungstate: Synthesis, structure and solution properties

“…The FT-IR spectrum of polyanion [34]. This is in line with the connection motif obtained from the crystal structure.…”

“…During our manuscript preparation we came across a study of Wang et al on a series of lanthanoid complexes containing phosphotungstate as a ligand, which were synthesized in a one-pot reaction in sodium acetate buffer. The alkali cations had to be replaced with organic cations through ion exchange in order to grow crystals of good quality [34]. It is to be noted that the title polyanions were obtained in CH 3 COOH-CH 3 COOK buffer solution different from the procedure developed by Mialane et al We have witnessed from our work on lanthanoid-containing POMs that the cations play a major role in the formation of nanoclusters so that the flexible and highly coordinated lanthanoid cations are excellent structural linkers [32,33].…”

Syntheses, structures and properties of a series of 3s–5d–4f mixed metal substituted sandwich-type arsenotungstates

“…There are two obvious absorption bands in the region of 190-400 nm, which can be observed at 193-194 nm and 246-247 nm for 1-3. Generally, the former can be assigned to the pπ-dπ charge transfer transitions of the O t →W bands whereas the latter is considered to the pπ-dπ charge-transfer transitions of the O b(c) →W bands [30].…”

The Syntheses, Structures, and Magnetic Properties of Four 2D Lanthanide(III)‐naphthalenedicarboxylic Complexes

“…Different from the magnetic character of Pr III and Nd III complexes, the 6 H ground state for the free Sm III cation in the crystal field is split into six states by spinorbit coupling, therefore, the crystal field effect and the possible thermal population of the high energy states should be considered for Sm (4). [24] The χ M T value is 0.036 emu·K· mol -1 at 2 K, which is evidently smaller than the theoretical value of 0.088 emu·K·mol -1 for one isolated Sm III cation, suggesting the occurrence of weak antiferromagnetic interactions between Sm III cations mediated by carboxylic oxygen atoms as well as the spin-orbital coupling and the crystal field effect. Moreover, the curve of χ M -1 vs. T does not obey the CurieWeiss law ( Figure S3, Supporting Information), which is similar to that reported for the Sm III complex.…”