Polyoxometalate Building Blocks Research Articles

A Novel Tri-Coordination Zinc Complex Functionalized Silicotungstate with ROS Catalytic Ability and Anti-Tumor Cells Activity

Reactive oxygen species (ROS) can be used as an effective method to treat tumors. Artificial oxidase has received increasing attention as a catalyst for ROS generation in fields ranging from bioinorganic chemistry to pharmaceutical chemistry. In this study, an artificial oxidase based on a binuclear zinc complex and Keggin-type silicotungstate [Zn2(4,4′-bpy)(Phen)2][SiW12O40] (ZSW) (4,4′-bpy = 4,4′-bipyridine; Phen = 1,10-phenanthroline) was synthesized and structurally featured in terms of its X-ray photoelectron spectrum (XPS), bond valence sum (Σs) calculation, IR spectra, and single-crystal X-ray diffraction (SXRD). ZSW is an ionic compound in which the cation is a binuclear zinc complex [Zn2(4,4′-bpy)(Phen)2]4+ and the anion is a α-Keggin-type silicotungstate [SiW12O40]4– cluster. Notably, the Zn ions in the [Zn2(4,4′-bpy)(Phen)2] exist in tri-coordination, which was first obtained in polyoxometalate (POM) chemistry. It was also demonstrated that ZSW is capable of efficiently catalyzing the production of ROS, which, according to the computational calculations, may be due to the synergistic action of zinc complexes and POM building blocks. Furthermore, ZSW exhibited inhibition ability toward ROS-sensitive tumor cells, such as PC12 cells.

Tetrahedral Connection of ε-Keggin-type Polyoxometalates To Form an All-Inorganic Octahedral Molecular Sieve with an Intrinsic 3D Pore System

A new type of polyoxometalate-based porous material was successfully synthesized. The new material is the first fully inorganic Keggin-type polyoxometalate-based microporous material with intrinsically ordered open micropores and is the third member of the small family of octahedral molecular sieves (OMSs). Twelve MoO6 or VO6 octahedra surround a central VO4 tetrahedron to form ε-Keggin polyoxometalate building blocks (ε-VMo9.4V2.6O40) that are linked by Bi(III) ions to form crystalline Mo-V-Bi oxide with a diamondoid topology. The presence of a tetrahedral shape of the ε-Keggin polyoxometalate building block results in arrangement of microporosity in a tetrahedral fashion which is new in OMSs. Owing to its microporosity, this Mo-V-Bi oxide shows zeolitic-like properties such as ion-exchange and molecule adsorption.

Observing Assembly of Complex Inorganic Materials from Polyoxometalate Building Blocks

Understanding the aqueous state of discrete metal-oxo clusters, prenucleation clusters, and even simple ions is valuable for controlling the growth of metal-oxide materials from water. Niobium polyoxometalates (Nb-POMs) are unique in the aqueous metal-oxo cluster landscape in their unusual solubility behavior: specifically, their solubility in water increases with increasing ion-pairing contact with their counterions, and thus provides a rare opportunity to observe these and related solution phenomena. Here, we isolate in the solid state the monomeric and dimeric building blocks, capped Keggin ions, of the extended Keggin chain materials that are now well-known: not only in Nb-POM chemistry, but Mo and V POM chemistry as well. Rb13[GeNb13O41]·23H2O (Rb1), Cs10.6[H2.4GeNb13O41]·27H2O (Cs1) and Cs18H6[(NbOH)SiNb12O40]2·38H2O (Cs2) were characterized by single-crystal X-ray diffraction. Small angle X-ray scattering (SAXS) of solutions of Rb1 and Cs1 in varying conditions revealed oligomerization of the monomers into chain structures: the extent of oligomerization is controlled by pH, concentration, and the counterion. We distinctly observe chains of up to six Keggin ions in solution, with the large alkali cations for charge-balance. This combined solid state and solution study reveals in great detail the growth of a complex material from discrete monomeric building blocks. The fundamentals of the processes we are able to directly observe in this study, ion-association and hydrolysis leading to condensation, universally control the self-assembly and precipitation of materials from water.

ChemInform Abstract: Surfactant‐Encapsulated Polyoxometalate Building Blocks: Controlled Assembly and Their Catalytic Properties

AbstractReview: 135 refs.

A building block strategy to access sulfur-functionalized polyoxometalate based systems using {Mo2S2O2} and {Mo3S4} as constitutional units, linkers or templates

The present tutorial review reports on the synthetic approaches for the formation of "polyoxothiometalate" compounds with special emphasis on the unique reactivity of the preformed sulfur-containing cationic building blocks {Mo(2)O(2)S(2)}(2+) and {Mo(3)S(4)}(4+) toward polyoxometalate building blocks. Such simple chemical systems, based on chemical and structural complementarities between ionic reactive moieties have led to the synthesis of a series of relevant clusters with unrivalled large nuclearity structural arrangements, such as loops, triangles, squares and boxes. Specific reaction parameters and considerations will be pointed out showing that a deliberate pure inorganic supramolecular chemistry based on weak interactions, flexibility and dynamic is possible with polyoxometalates.

A 12-molybdophosphoric acid supramolecular compound: Synthesis, crystal structure and photochromic properties

A new 12-molybdophosphoric acid supramolecular compound based on Keggin polyoxometalate building blocks, (C 6H 6NO 2)·(C 5H 6N) 2·[PMo 12O 40]·(C 6H 5NO 2)·2H 2O ( 1), has been conventionally synthesized and structurally characterized by elemental analyses, the powder X-ray diffraction (XRD), TG, IR, and single crystal X-ray diffraction, respectively. Compound 1 is composed of polyoxometalate anions [PMo 12O 40] 3−, pyridinium cations, 4-carboxylpyridinium cation and lattice water. A three-dimensional network is formed by N–H⋯O, C–H⋯O and O–H⋯O hydrogen-bond interactions. In addition, the supramolecular compound shows photochromism.

Keeping the Ball Rolling: Fullerene-like Molecular Clusters

The discovery of fullerenes in 1985 opened a new chapter in the chemistry of highly symmetric molecules. Fullerene-like metal clusters, characterized by (multi)shell-like structures, are one rapidly developing class of molecules that share this shape. In addition to creating aesthetically pleasing molecular structures, the ordered arrangement of metal atoms within such frameworks provides the opportunity to develop materials with properties not readily achieved in corresponding mononuclear or lower-nuclearity complexes. In this Account, we survey the great variety of fullerene-like metal-containing clusters with an emphasis on their synthetic and structural chemistry, a first step in the discussion of this fascinating field of cluster chemistry. We group the compounds of interest into three categories based on the atomic composition of the cluster core: those with formal metal-metal bonding, those characterized by ligand participation, and those supported by polyoxometalate building blocks. The number of clusters in the first group, containing metal-metal bonds, is relatively small. However, because of the unique and complex bonding scenarios observed for some of these species, these metalloid clusters present a number of research questions with significant ramifications. Because these cores contain molecular clusters of precious metals at the nanoscale, they offer an opportunity to study chemical properties at size ranges from the molecular to nanoscale and to gain insights into the electronic structures and properties of nanomaterials of similar chemical compositions. Clusters of the second type, whose core structures are facilitated by ligand participation, could aid in the development of functional materials. Of particular interest are the magnetic clusters containing both transition and lanthanide elements. A series of such heterometallic clusters that we prepared demonstrates diverse magnetic properties including antiferromagnetism, ferrimagnetism, and ferromagnetism. Considering the diversity of their composition, their distinct electronic structures, and the disparate coordination behaviors of the different metal elements, these materials suggest abundant opportunities for designing multifunctional materials with varied structures. The third type of clusters that we discuss are based on polyoxometalates, in particular those containing pentagonal units. However, unlike in fullerene chemistry, which does not allow the use of discrete pentagonal building blocks, the metal oxide-based pentagonal units can be used as fundamental building blocks for constructing various Keplerate structures. These structures also have a variety of functions, including intriguing magnetic properties in some cases. Coupled with different linking groups, such pentagonal units can be used for the assembly of a large number of spherical molecules whose properties can be tuned and optimized. Although this Account focuses on the topological aspects of fullerene-like metal clusters, we hope that this topical review will stimulate more efforts in the exploratory synthesis of new fullerene-like clusters. More importantly, we hope that further study of the bonding interactions and properties of these molecules will lead to the development of new functional materials.

ChemInform Abstract: Synthesis of Orthorhombic Mo‐V‐Sb Oxide Species by Assembly of Pentagonal Mo6O21 Polyoxometalate Building Blocks.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

A new 3-fold interpenetration of diamond-like network constructed from polyoxometalate building blocks

A new complex based on Keggin polyoxometalate building blocks, [Cu2(bpy)2(Hbpy)(H2O)](PW12O40) (1) (bpy = 4,4′-bipyridine), has been hydrothermally synthesized and characterized by elemental analyses, IR, TG and X-ray single crystal diffraction. The X-ray structure analysis reveals that complex 1 exhibits an unprecedented 3-fold interpenetration of diamond-like network in the polyoxometalate chemistry.

Synthesis of Orthorhombic Mo‐V‐Sb Oxide Species by Assembly of Pentagonal Mo6O21 Polyoxometalate Building Blocks

AbstractGute Mischung: Der pentagonale Polyoxomolybdat‐Baustein [Mo6O21]n− vereinigt sich mit anderen Mo‐, V‐ und Sb‐haltigen Ionen zu einem orthorhombischen Mo‐V‐Sb‐Oxid. Die erste Einkristall‐Röntgenstrukturanalyse eines orthorhombischen Mo‐V‐Mischoxids, das als Katalysator für die selektive Oxidation leichter Alkane infrage kommt, charakterisiert die Struktur der Verbindung.magnified image

Synthesis of Orthorhombic Mo‐V‐Sb Oxide Species by Assembly of Pentagonal Mo6O21 Polyoxometalate Building Blocks

Mix and match: The pentagonal [Mo(6)O(21)](n-) polyoxomolybdate building block assembles with other sources of Mo, V, and Sb ions to form an orthorhombic Mo-V-Sb oxide. The first single-crystal X-ray analysis of an orthorhombic Mo-V-based oxide, a promising catalyst for light alkane selective oxidation known as the "M1 phase", revealed the structure of the compound.

Solvothermal synthesis, structure and properties of two new compounds based on Keggin polyoxometalates decorated by copper complexes

Two new organic-inorganic hybrid compounds based on polyoxometalate building blocks, [CuI(bpy)2]2{[CuII(bpy)]2 O40} (1), H[Cu(bpy)(H2O)]{[Cu(bpy)]4(PO4)2}{PW11 CuO39} · H2O (2) (bpy = 2,2′-bipyridine), have been solvothermally synthesized and characterized by elemental analyses, IR, and TG analysis. Single crystal X-ray diffraction reveals that 1 is built from the reduced α-Keggin polyoxoanion [O40]6− bicapped by two [CuII(bpy)]2+ through four bridging oxo groups on two opposite [Mo4O4] faces. 1 shows mild photoluminescence in the solid state at room temperature. 2 is based on monovacant Keggin anion {PW11CuO39}5− linked through Cu(bpy)2+ and, generating a one-dimensional chain. Magnetism indicates predominantly antiferromagnetic interaction in 2.

Chiral Self-Threading Frameworks Based on Polyoxometalate Building Blocks Comprising Unprecedented Tri-Flexure Helix

Two enantiomeric chiral 3D frameworks were constructed by using an achiral ligand, nickel cations, and polyoxometalate ions as building blocks, which not only comprise unusual triflexural helical motifs but also represent the first 3D self-threading examples.

Self-Assembly of Extended High-Dimensional Architectures from Anderson-type Polyoxometalate Clusters

Three unusual compounds based on polyoxometalate building blocks, [(C6H5NO2)2Ln(H2O)4]2[IMo6O24][NO3]·4H2O (Ln = Ce 1 and La 2) and [(H2O)4Ag3][Cr(OH)6Mo6O18]·3H2O 3, have been synthesized and characterized by elemental analysis, IR and X-ray photoelectron spectroscopy, thermogravimetry analysis, and single-crystal X-ray diffraction. Compounds 1 and 2 are isostructural and possess a unique two-dimensional (2D) network, which is composed of rare earth coordination polymer chains joint together by [IMo6O24]5- polyoxoanions, representing the first example of 2D inorganic−organic hybrid compounds based on A-type Anderson polyoxoanions. Compound 3 is constructed from B-type Anderson polyoxoanions [Cr(OH)6Mo6O18]3- and silver (I) ions to yield a three-dimensional (3D) open framework containing “guest” water molecules. To our best knowledge, it is the first time Anderson-type polyoxometalate motifs have been connected with silver ions to construct a 3D covalent framework.

Self-Assembly of a Series of Extended Architectures Based on Polyoxometalate Clusters and Silver Coordination Complexes

Three unusual compounds based on polyoxometalate building blocks, [(H2O)5Na2(C6NO2H4)(C6NO2H5)3Ag2][Ag2IMo6O24(H2O)4] x 6.25H2O (1), [(H2O)4Na2(C6NO2H5)6Ag3][IMo6O24] x 6H2O (2), and (C6NO2H6)2[(C6NO2H5)2Ag][Cr(OH)6Mo6O18] x 4H2O (3), have been synthesized and characterized by elemental analysis; IR, XPS, and ESR spectroscopy; TG analysis; and single-crystal X-ray diffraction. Compound 1 is constructed from the cationic two-dimensional (2D) coordination polymer sheets which are constituted of [(H2O)5Na2(C6NO2H4)(C6NO2H5)3Ag2]3+ and anionic [Ag2IMo6O24(H2O)4]3- chains as pillars, forming a three-dimensional (3D) supramolecular framework via weak Ag-O interactions. Compound 2 is composed of the well-defined [IMo6O24]5- building blocks, which are linked through trinuclear Ag-pyridine-3-carboxylic acid, [(C6NO2H5)6Ag3]3+, fragments into a one-dimensional (1D) hybrid chain; adjacent chains are further connected by sodium cations to yield a novel 2D network. Compound 3 has a 1D chainlike structure constructed from [Cr(OH)6Mo6O18]3- building blocks and Ag-pyridine-4-carboxylic acid coordination units. The crystal data for these compounds are the following: 1, triclinic, P1, a = 13.280(3) A, b = 13.641(3) A, c = 16.356(3) A, alpha = 89.68(3) degrees, beta = 88.31(3) degrees, gamma = 75.87(3) degrees, Z = 2; 2, triclinic, P1, a = 11.978(2) A, b = 12.008(2) A, c = 13.607(3) A, alpha = 116.14(3) degrees, beta = 108.85(3) degrees, gamma = 93.86(3) degrees, Z = 1; 3, triclinic, P1, a = 10.458(2) A, b = 10.644(2) A, c = 12.295(3) A, alpha = 97.40(3) degrees, beta = 112.38(3) degrees, gamma = 113.59(3) degrees, Z = 1.

ChemInform Abstract: Formation of Unsymmetrical Polyoxotungstates via Transfer of Polyoxometalate Building Blocks. NMR Evidence Supports the Kinetic Stability of the Pentatungstate Anion, [W5O18]6‐, in Aqueous Solution.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Porous Crystal Formation from Polyoxometalate Building Blocks: Single-Crystal Structure of [AlO4Al12(OH)12(H2O)24][Al(OH)6Mo6O18]2((OH)·29.5H2O [J. Am. Chem. Soc. 2000, 122, 7432−7433

ADVERTISEMENT RETURN TO ISSUEPREVAddition/CorrectionNEXTORIGINAL ARTICLEThis notice is a correctionPorous Crystal Formation from Polyoxometalate Building Blocks: Single-Crystal Structure of [AlO4Al12(OH)12(H2O)24][Al(OH)6Mo6O18]2((OH)·29.5H2O [J. Am. Chem. Soc.2000, 122, 7432−7433].Jung-Ho Son, Hyuk Choi, and Young-Uk KwonCite this: J. Am. Chem. Soc. 2000, 122, 42, 10492Publication Date (Web):October 10, 2000Publication History Published online10 October 2000Published inissue 1 October 2000https://doi.org/10.1021/ja004660fCopyright © 2000 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views404Altmetric-Citations-LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (11 KB) Get e-Alerts Get e-Alerts

Porous Crystal Formation from Polyoxometalate Building Blocks: Single-Crystal Structure of [AlO4Al12(OH)12(H2O)24][Al(OH)6Mo6O18]2((OH)· 29.5H2O

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTADDITION / CORRECTIONThis article has been corrected. View the notice.Porous Crystal Formation from Polyoxometalate Building Blocks: Single-Crystal Structure of [AlO4Al12(OH)12(H2O)24][Al(OH)6Mo6O18]2((OH)· 29.5H2OJung-Ho Son, Hyuk Choi, and Young-Uk KwonView Author Information Department of Chemistry, Sungkyunkwan University Suwon 440-746, Korea Cite this: J. Am. Chem. Soc. 2000, 122, 30, 7432–7433Publication Date (Web):July 15, 2000Publication History Received13 March 2000Published online15 July 2000Published inissue 1 August 2000https://doi.org/10.1021/ja000884mCopyright © 2000 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views970Altmetric-Citations76LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit Read OnlinePDF (195 KB) Get e-AlertsSupporting Info (1)»Supporting Information Supporting Information SUBJECTS:Cluster chemistry,Cluster ions,Crystal structure,Metal clusters,Nanocomposites Get e-Alerts