Self-Assembly of Nanoscale Lanthanoid-Containing Selenotungstates: Synthesis, Structures, and Magnetic Studies

Abstract

The reaction of mid-lanthanide (Ln) ions with the preformed {Se 6 W 39 } precursor under reasonably acidic aqueous conditions in the presence of organic amine cations results in an unprecedented nanoscale lanthanide-functionalized polyoxotungstate family, which are rare examples of mid-lanthanide-containing selenotungstates. (C 4 H 1 0 NO) 9 Na 3 -[Dy 3 Se 3.5 W 30 O 107.5 (H 2 O) 10 ]•22H 2 O (1) and (NH 4 ) 3 (C 2 H 8 N)-Na 2 [Dy 4 Se 6 W 38 O 132 (H 2 O) 26 (OH) 6 ]•18H 2 O (2) reveal a trimeric Keggin assembly and a cyclic {Se 6 W 38 }-based chain, respectively, whereas (NH 4 ) 4 Na 8 [Gd 4 S e 6 W 4 8 O 1 6 6 (H 2 O) 2 0 (OH) 4 ] • 2 1H 2 O (3 ) and (NH 4 ) 9 (C 2 H 8 N) 4 Na 5 [Ln 6 Se 6 W 58 O 202 (H 2 O) 20 (OH) 4 ]•58H 2 O (4; Ln = Gd, Tb, or Dy) are a few examples of polyoxometalates consisting of both classical Keggin and Wells− Dawson building blocks, and (NH 4 ) 4 (C 2 H 8 N) 5 Na 13 [Ln 4 Se 8 W 56 O 196 (H 2 O) x (OH) 10 ]•40H 2 O (5; Ln = Gd, Tb, or Dy; x = 12 for Gd and Tb and 10 for Dy) features the largest "pure" Wells−Dawson selenotungstate {Se 8 W 56 } bearing a length of 3.73 nm. A library of Se-templated species involving the first reported Keggin {α-SeW 8 } and Wells−Dawson {α-Se 2 W 16 } building blocks as well as some decisive assembly factors during the synthesis is responsible for these architectures. All of the compounds were structurally characterized in the solid and solution by single-crystal X-ray diffraction, IR, thermogravimetric−differential thermal analysis, and electrospray ionization mass spectrometry. Magnetic properties indicate that 1 and 4-Dy show probable single-molecule-magnet behavior with obvious frequency dependence, whereas 3 and 4-Gd present the antiferromagnetic interactions between the Gd III centers.

Gd3 Triangles in a Polyoxometalate Matrix: Tuning Molecular Magnetocaloric Effects in {Gd30M8} Polyoxometalate/Cluster Hybrids Through Variation of M2+

“…[1][2][3] Among these, POM/ coordination cluster (CC) hybrids are becoming increasingly well-established with examples combining POMs with various 3d and/or rare-earth ions, the majority of the latter involving diamagnetic species such as Y III and La III . [4][5][6][7][8][9][10][11] In a class of their own are the highly symmetric spherical Keplerate systems. These have received much attention not only because of their aesthetically beautiful structures but also because of their interesting properties.…”

A Purely Inorganic Quasi‐Keggin Polyoxometalate for Photocatalytic Conversion of Carbon Dioxide to Carbon Monoxide

“…[33,34] Therefore, a Cocontaining material based on {P 4 Mo 6 } cluster might be an attractive candidate towards photocatalytic CO 2 RR. Furthermore, a majority of research works related to trimeric/tetrameric species have exclusively focused on Keggin/ Dawson units, [35][36][37]…”

“…Furthermore, a majority of research works related to trimeric/tetrameric species have exclusively focused on Keggin/Dawson units, [35–37] but with rare examples based on {P 4 Mo 6 } being reported until now. Based on the above considerations, we elaborately design and synthesize one pure inorganic 3D compound based on {P 4 Mo 6 } units, H 47 Na 2 Co 4 Mo 24 (PO 4 ) 11 O 72 ⋅ 15H 2 O ({ Co 4 Mo 24 }), which is successfully coupled with cobalt metals.…”

Synthesis, Characterization, Electrochemistry, Photoluminescence and Magnetic Properties of a Dinuclear Erbium(III)-Containing Monolacunary Dawson-Type Tungstophosphate: [{Er(H2O)(CH3COO)(P2W17O61)}2]16−

“…Focusing only on Ln-containing POMs (Ln-POMs); lacunary POMs with nucleophilic oxygen centers are ideal multidentate ligands for lanthanide ions owing to their high oxophilic nature. In addition, Ln ions can have high coordination numbers, thus they can link POM building blocks to create discrete giant Ln-POM structures or polymeric networks (1D, 2D and 3D extended POMs) [ 6 , 7 , 8 , 9 , 10 ]. However, in Ln-POMs due to their larger sizes and consequently larger coordination numbers compared to 3d metal ions, the formation of lanthanide-oxo-hydroxo clusters within the POM framework has been rarely observed [ 9 , 11 , 12 ].…”