Nicotinic-Acid-Ornamented Tetrameric Rare-Earth-Substituted Phospho(III)tungstates with the Coexistence of Mixed Keggin/Dawson Building Blocks and Its Honeycomb Nanofilm for Detecting Toxins

A fascinating class of nicotinic-acid-ornamented tetrameric rare-earth (RE)-substituted phospho(III)tungstates [NH₂(CH₃)₂]₁₀Na₄H₈[RE₂(NA)(HNA)(H₂O)₆(W₂O₄)(β-H₂P₂^IIIW₁₃O₄₉)(α-HP^IIIW₉O₃₃)]₂·22 H₂O [RE = Nd³⁺ (1-Nd), Tb³⁺ (2-Tb), Dy³⁺ (3-Dy), Ho³⁺ (4-Ho), HNA = nicotinic acid] were isolated through a one-step reaction method of Na₂WO₄·2H₂O, H₃PO₃, HNA, NH₂(CH₃)₂·HCl, and RE(NO₃)·6H₂O. Of meticulous concern is that HPO₃^2- was used as a template to construct tetrameric RE-substituted phospho(III)tungstates including mixed heteropolyoxotungstate building blocks. Their hybrid polyoxoanions are composed of two symmetrical [RE₂(NA)(HNA)(H₂O)₆(W₂O₄)(β-H₂P₂^IIIW₁₃O₄₉)(α-HPW₉O₃₃)]^11- units linked by RE-O-W bonds. The symmetrical unit consists of one peculiar heterometal nicotinic-acid-ornamented [RE₂(NA)(HNA)(W₂O₄)]⁹⁺ cluster connecting a pentavacant Dawson-like [β-H₂P₂W₁₃O₄₉]^12- and a trivacant Keggin [α-HPW₉O₃₃]^8- subunits. Furthermore, dimethyldioctadecylammonium chloride (DMDODA·Cl) was used to combine with 1-Nd in the CHCl₃-H₂O system through electrostatic interactions, leading to the 1-Nd@DMDODA composite material. The honeycomb-patterned film of the 1-Nd @DMDODA composite material was successfully constructed by using the breath figure method on a glassy carbon electrode, which can offer abundant binding sites to Au nanoparticles (nano-Au). Ulteriorly, Au-functionalized 1-Nd@DMDODA-modified electrode was utilized as an electrochemical sensor to detect ochratoxin A, showing a good detection limit of 1.19 pM.

Multinuclear Lanthanide-Implanted Tetrameric Dawson-Type Phosphotungstates with Switchable Luminescence Behaviors Induced by Fast Photochromism

A series of benzoate-decorated lanthanide (Ln)-containing tetrameric Dawson-type phosphotungstates [N(CH₃)₄]₆H₂₀[{(P₂W₁₇O₆₁)Ln(H₂O)₃Ln(C₆H₅COO)(H₂O)₆]}{[(P₂W₁₇O₆₁)Ln(H₂O)₃}]₂Cl₂·98H₂O [Ln = Sm (1), Eu (2), and Gd (3)] were made using a facile one-step assembly strategy and characterized by several techniques. Notably, the Ln-containing tetrameric Dawson-type polyoxoanions [{(P₂W₁₇O₆₁)Ln(H₂O)₃Ln(C₆H₅COO)(H₂O)₆]}{[(P₂W₁₇O₆₁)Ln(H₂O)₃}]₂^24- are all established by four monolacunary Dawson-type [P₂W₁₇O₆₁]^10- segments, encapsulating a Ln³⁺ ion with two benzoates coordinating to the Ln³⁺ ions. 1-3 exhibit reversible photochromism, which can change from intrinsic white to blue for 6 min upon UV irradiation, and their colors gradually recover for 30 h in the dark. The solid-state photoluminescence spectra of 1 and 2 display characteristic emissions of Ln components based on 4f-4f transitions. Time-resolved emission spectra of 1 and 2 were also measured to authenticate the energy transfer from the phosphotungstate and organic chromophores to Eu³⁺. In particular, 1 shows an effectively switchable luminescence behavior induced by its fast photochromism.

Synthesis, characterization, and photoluminescence properties of three two-dimensional lanthanide-containing Dawson-type polyoxometalates

Three isostructural lanthanide-containing polyoxometalates with 2D network architectures were successfully obtained under hydrothermal conditions.

Discovery and isolation of the trans-isomers of two 1 : 2-type lanthanide-containing monolacunary Dawson-type tungstophosphates: [LnIII(α2-P2W17O61)2]17− (Ln = La, Ce)

Two novel trans-isomers of 1 : 2-type lanthanide-containing monolacunary Dawson-type tungstophosphates [Ln(α₂-P₂W₁₇O₆₁)₂]¹⁷⁻ (Ln = La^III (1), Ce^III (2)) were successfully isolated and characterized.

An unprecedented 3D architecture based on a Nb/W mixed-addendum polyoxometalate and lanthanide–organic complex: synthesis, crystal structure and properties

For the first time, a 3D framework based on lanthanide-containing Nb/W mixed-addendum polyoxometalate has been obtained by utilizing the steam-assisted conversion method.

Significant developments in rare-earth-containing polyoxometalate chemistry: synthetic strategies, structural diversities and correlative properties

In this article, the major progress in rare-earth containing polyoxometalates made in the past decade involving synthetic strategies, structural characteristics and some significant properties related to optics, catalysis and magnetism is highlighted and discussed.

An ultrastable, flexible POM-based coordination polymer with redox properties

A new porous coordination polymer (1) has been prepared under hydrothermal conditions. The flexible framework of1shows dynamic behavior accompanied with the removal/adsorption of guest water molecules. Remarkably, crystals of1can remain intact even in 8 mol L⁻¹hydrochloric acid, dilute NaOH solution (pH = 12) and boiling water.