Two types of novel tetra-iron substituted sandwich-type arsenotungastates with supporting lanthanide pendants

Abstract

Two classes of novel tetra-iron substituted sandwich-type arsenotungastates (ATs) with supporting lanthanide (Ln) pendants KNa2 [Ln(H2O)7][Fe4(H2O)10(B-β-AsW9O33)2]·21H2O [Ln = La(III) (1), Pr(III) (2), Nd(III) ()3, Sm(III) (4)] and [Ln(H2O)8]2[Fe4(H2O)8(l-thr)2(B-β-AsW9O33)2]·20H2O [Ln = La(III) (5), Pr(III) ()6, Nd(III) (7), Sm(III) (8), Eu(III) (9), Gd(III) (10), Tb(III) (11), Dy(III) (12), Er(III) (13)] (l-thr = l-threonine) have been synthesized by the hydrothermal reaction of the [As2W19O67(H2O)](14-) precursor with Fe(3+) cations and Ln(3+) cations in the presence of l-thr or l-leucine and l-alanine, and further characterized by elemental analyses, IR spectra and single-crystal X-ray diffraction. Structural analyses indicate that 1-4 display the inorganic 2-D sheet architecture constructed from tetra-iron sandwiched AT [Fe4(H2O)10(B-β-AsW9O33)2](6-) fragments by bridging [Ln(H2O)7](3+) cations whereas the molecular structures of the isostructural 5-13 consist of an organic-inorganic hybrid tetra-iron substituted sandwich-type AT [Fe4(H2O)8(l-thr)2(B-β-AsW9O33)2](6-) fragment and two pendant [Ln(H2O)8](3+) cations. As far as we know, 1-4 represent the rare inorganic 2-D extended ATs based on transition-metal substituted sandwich-type polyoxometalate units and Ln linkers and 5-13 are the first Fe-Ln heterometallic ATs with amino acid ligands. The solid state photoluminescence (PL) measurements of 9 and 11 have been performed at room temperature. The PL emission of 9 is mainly derived from the characteristic (5)D0 → (7)F2 (J = 4-0) transitions of the Eu(III) cations whereas the PL behavior of 11 stems from the common contribution of the (5)D4 → (7)FJ (J = 5-3) transitions of the Tb(III) ions and oxygen-to-metal (O → W) charge-transfer transitions of AT segments. The thermogravimetric (TG) analyses of 1-4 and 6-12 have been investigated.

Structural Transformation from Dimerization to Tetramerization of Serine‐Decorated Rare‐Earth‐Incorporated Arsenotungstates Induced by the Usage of Rare‐Earth Salts

“…Similar observations were encountered in our previous studies . Under similar experimental conditions, the solid‐state PL properties of 2‐Tb , 2‐Dy , 2‐Ho , 2‐Er , and 2‐Tm were also investigated at room temperature (Figure S18 in the Supporting Information), which were very similar to 1‐Tb , 1‐Dy , 1‐Ho , 1‐Er , and 1‐Tm ; furthermore, all of these compounds displayed characteristic emission bands that originate from f–f transitions in RE 3+ ions.…”

Research progress on polyoxometalate-based transition-metal–rare-earth heterometallic derived materials: synthetic strategies, structural overview and functional applications

“…[111][112][113][114][115][116][117][118][119][120][121][122] In the following years, the appearance of some gigantic PTRHDMs also prove that this method is very effective. 127,130,131,143,144,146 125,126,128,132,[134][135][136][137][138][139][140][141]145,147,148,[151][152][153][154][155][156][157][158]160,161,165,167,168 During the course of the preparation of PTHRDMs, both synthetic methods have their own advantages. The merits of CASS include:…”

Lanthanide-Connecting and Lone-Electron-Pair Active Trigonal-Pyramidal-AsO3 Inducing Nanosized Poly(polyoxotungstate) Aggregates and Their Anticancer Activities

“…Due to the existence of the trivacant Keggin [B-α-AsW 9 O 33 ] 9− fragments in the skeletons of 1 – 8 , IR spectra in the low wave-number region all exhibit four similar characteristic terminal ν (W−O t ), ν (As−O a ), corner-sharing ν (W−O b ) and edge-sharing ν (W−O c ) asymmetric stretching vibration modes, which are seen at 948–952 cm −1 , 862–869 cm −1 , 783–786 cm −1 and 707–713 cm −1 , respectively (Figure S15)5051. In their high wave-number region, an obvious broad band in the range of 3438–3446 cm −1 corresponds to the ν(O−H) stretching mode of lattice or coordination water molecules.…”