Polyoxometalate

About: Polyoxometalate is a research topic. Over the lifetime, 3493 publications have been published within this topic receiving 94123 citations. The topic is also known as: POM.

Self-assembly of organic-inorganic hybrid materials constructed from eight-connected coordination polymer hosts with nanotube channels and polyoxometalate guests as templates.

Abstract: Two polyoxometalate-templated organic–inorganic hybrid porous frameworks, namely, [Cu2(H2O)2(bpp)2Cl][PM12O40]·∼20H2O (for 1, M = W; for 2, M = Mo; bpp = 1,3-bis(4-pyridyl)propane), were self-assembly obtained and structurally determined by elemental analyses, inductively coupled plasma analyses, infrared spectroscopy, and single-crystal X-ray diffraction analyses. Single-crystal X-ray analysis of these crystals revealed that both of the structures are constructed from eight-connected three-dimensional coordination polymer hosts [Cu2(H2O)2(bpp)2Cl]n3n+ and ball-shaped Keggin-type guests [PM12O40]n3n− as templates. The polymer hosts resulted from a bcc-type framework with nanotubes, and the nanotubes can be regarded as a tetra-stranded helix structure. Furthermore, compounds 1 and 2 exhibit photoluminescent properties at ambient temperature, and the compound 2 bulk-modified carbon paste electrode (2-CPE) displays good electrocatalytic activity toward the reduction of nitrite.

Protonation, Oligomerization, and Condensation Reactions of Vanadate(V), Molybdate(vi), and Tungstate(vi)

Abstract: Publisher Summary This chapter discusses protonation, oligomerization, and condensation reactions of vanadate(V), molybdate(VI), and tungstate(VI). The elements vanadium, molybdenum, and tungsten in their high oxidation states form the stable oxyanions [VO4]3-, [MoO4]2-, and [WO4]2-. In aqueous solution, these ions are easily protonated and show a strong tendency to form polyoxoanions by oxygen bridging, and the release of water molecules. Depending on pH and concentration, a great variety of ions can form in each case, giving rise to complex systems of simultaneous equilibria, which have proved difficult to characterize with certainty. The molybdate(VI) system, in particular, needs further clarification regarding the existence of some polyions. More kinetic and thermodynamic data would also help to improve the understanding of these systems and lead to a general inclusive explanation of the mechanism of polyoxoanion formation. In this respect, new information about some structural preferences of the different metals in mixed polyoxoanions is a useful addition to known facts regarding polyoxometalate structures.

Acid-induced surface functionalization of polyoxometalate by enclosure in a polyhedral silver-alkynyl cage.

Abstract: Surface functionalization of polyoxometalate anions with silver(I) tert-butylethynide in an organic solution medium has been achieved for the first time using an acid-induced facile approach. The generated neutral hybrid monomeric complexes [Ag40(C≡CtBu)22(CF3COO)12(V10O28)]·4CH3OH (1) and [Ag40(C≡CtBu)20(CF3COO)12(Mo6O22)]·2CH3OH (2) constitute members of a new silver(I)−polyoxometalate family in which the polyoxometalate anion is embedded in a polyhedral silver(I) cluster assembled by multiple argentophilic Ag···Ag interactions.

Hybrid Organic–Inorganic 1D and 2D Frameworks with ε-Keggin Polyoxomolybdates as Building Blocks

Abstract: Organic-inorganic hybrid materials based on polyoxometalate building blocks with capping La 3 + ions and bidentate oxygenated ligands have been obtained by reaction at room temperature of the [e-PMo 1 2 O 3 6 -(OH 4 {La(H 2 O) 4 )] 5 + polyoxocation with glutarate (C 5 H 6 O 2 2-) and squarate (C 4 O 4 2-) organic ligands. [e-PMo 1 2 O 3 7 -(OH) 3 {La(H 2 O) 4 (C 5 H 6 O 4 ) 0 . 5 } 4 ].21 H 2 O (1) and [e-PMo 1 2 O 3 9 (OH){La(H 2 O) 6 } 2 -(La(H 2 O) 5 (C 4 O 4 ) 0 . 5 } 2 ].17H 2 O (2) form unprecedented 1D chains built from alternating polyoxocations and organic ligands connected through La-O links. The structures of these materials are compared to the 2D hybrid organic-inorganic framework [NC 4 H 1 2 ] 2 -[Mo 2 2 O 5 2 (OH) 1 8 {La(H 2 O) 4 } 2 {La(CH 3 CO 2 ) 2 } 4 ].8H 2 O (3) isolated from the hydrothermal reaction of elemental precursors (MoO 4 2-, Mo, La 3 + ) in acetate buffer. Compound 3 is built from previously undescribed polyoxometalate units with twenty-two MO v centers capped by six La 3 + ions, four of which are bridged by acetate ligands.