A reduced polyoxomolybdenum borophosphate anion related to the Wells-Dawson clusters

The Intrinsic Charge Carrier Behaviors and Applications of Polyoxometalate Clusters Based Materials

Polyoxometalates (POMs) are a series of molecular metal oxide clusters, which span the two domains of solutes and solid metal oxides. The unique characters of POMs in structure, geometry, and adjustable redox properties have attracted widespread attention in functional material synthesis, catalysis, electronic devices, and electrochemical energy storage and conversion. This review is focused on the links between the intrinsic charge carrier behaviors of POMs from a chemistry-oriented view and their recent ground-breaking developments in related areas. First, the advantageous charge transfer behaviors of POMs in molecular-level electronic devices are summarized. Solar-driven, thermal-driven, and electrochemical-driven charge carrier behaviors of POMs in energy generation, conversion and storage systems are also discussed. Finally, present challenges and fundamental insights are discussed as to the advanced design of functional systems based upon POM building blocks for their possible emerging application areas.

Polyoxometalates in dye-sensitized solar cells

Dye-sensitized solar cells (DSSCs) are the third generation of photovoltaic cells developed by Grätzel and O'Regan. They have the characteristics of low cost, simple manufacturing process, tunable optical properties, and higher photoelectric conversion efficiency (PCE). With an ever increasing energy crisis, there is an urgent need to develop highly efficient, environmentally benign, and energy-saving cell materials. Polyoxometalates (POMs), a kind of molecular inorganic quasi-semiconductor, are promising candidates for use in different parts of DSSCs due to their excellent photosensitivity, redox, and catalytic properties, as well as their relative stability. Following a brief introduction to the development of DSSCs and the potential virtues of POMs in DSSCs, we attempt to make some generalizations about the energy level regulation of POMs that is the underlying theoretical basis for their application in DSSCs, and then we summarize the research progress of POMs in DSSCs in recent years. This is organized in terms of the properties of POMs, namely, electron acceptor, photosensitivity, redox and catalysis, based on the accumulation of our research into POMs over many years. Meanwhile, in view of the fact that the properties of POMs depend primarily on their electronic structural diversity, we keep this point in mind throughout the article with a view to revealing their structure-property relationships. Finally we provide a short summary and remarks on the future outlook. This review may be of interest to synthetic chemists devoted to designing POMs with specific structures, and researchers engaged in the extension of POMs to photoelectric materials.

Ba3Ca4(BO3)3(SiO4)Cl: a new non-centrosymmetric complex alkaline-earth metal borosilicate chloride with a deep-ultraviolet cut-off edge

The first complex alkaline-earth metal borosilicate chloride, Ba₃Ca₄(BO₃)₃(SiO₄)Cl, as a potential ultraviolet nonlinear optical material.

Ionothermal Synthesis in an Ionic Liquid and Crystal Structure of [C4H12N2] [CoCl4]

The compound [C4H12N2][CoCl4] was ionothermally synthesised in an ionic liquid medium and shown by X-ray single crystal diffraction analysis to consist of four piperazinium C4H12N22+ cations and four CoCl42- complex anions. Thermogravimetric analysis indicated that [C4H12N2][CoCl4] possesses good thermal stability below 320 °C.

A new 3-D open-framework cadmium borovanadate with plane-shaped channels and high catalytic activity for the oxidation of cyclohexanol

A new 3-D open-framework cadmium borovanadate with 6-connected topology was hydrothermally obtained and structurally characterized. It not only features new cadmium(II) borovanadate which possesses an open-framework structure with unique plane-shaped channels, but also exhibits interesting absorption properties and high catalytic activities for the oxidation of cyclohexanol.

A novel open-framework copper borophosphate containing 1-D borophosphate anion with 10-MR windows and 12-MR channels

The open-framework copper borophosphate not only features novel borophosphate anionic partial structure containing 1-D 12-MR channels, but also exhibits ferromagnetic interactions and high catalytic activity for the oxidative degradation of chitosan.

Syntheses, Structures, Ionic Conductivities, and Magnetic Properties of Three New Transition-Metal Borophosphates Na5(H3O){MII3[B3O3(OH)]3(PO4)6}·2H2O (MII = Mn, Co, Ni)

Three new open-framework transition-metal borophosphates Na5(H3O){M(II)3[B3O3(OH)]3(PO4)6}.2H2O (M(II) = Mn, Co, Ni) (denoted as MBPO-CJ25) have been synthesized under mild hydrothermal conditions. Single-crystal X-ray diffraction analyses reveal that the three compounds possess isostructural three-dimensional (3D) open frameworks with one-dimensional 12-ring channels along the [001] direction. Notably, the structure can also be viewed as composed of metal phosphate layers [M(II)(PO4)2]4- with Kagomé topology, which are further connected by [B3O7(OH)] triborates, giving rise to a 3D open framework. The guest water molecules locate in the 12-ring channels. Partial Na+ ions reside in the 10-ring side pockets within the wall of the 12-ring channels, and the other Na+ ions and protonated water molecules locate in the 6-ring windows delimited by MO6 and PO4 polyhedra to compensate for the negative charges of the anionic framework. These compounds show a high thermal stability and are stable upon calcinations at ca. 500 degrees C. Ionic conductivities, due to the motion of Na+ ions, are measured for these three compounds. They have similar activation energies of 1.13-1.25 eV and conductivities of 2.7 x 10(-7)-9.9 x 10(-7) S cm(-1) at 300 degrees C. Magnetic measurements reveal that there are very weak antiferromagnetic interactions among the metal centers of the three compounds. Crystal data: MnBPO-CJ25, hexagonal, P6(3)/m (No. 176), a = 11.9683(5) A, c = 12.1303(6) A, and Z = 2; CoBPO-CJ25, hexagonal, P6(3)/m (No. 176), a = 11.7691(15) A, c = 12.112(2) A, and Z = 2; NiBPO-CJ25, hexagonal, P6(3)/m (No. 176), a = 11.7171(5) A, c = 12.0759(7) A, and Z = 2.

Chain Structures in Alkali Metal Borophosphates: Synthesis and Characterization of K3[BP3O9(OH)3] and Rb3[B2P3O11(OH)2]

Two new alkali metal borophosphates, K3[BP3O9(OH)3] and Rb3[B2P3O11(OH)2], were synthesized by applying solvothermal techniques using ethanol as solvent. The crystal structures were solved by means of single-crystal X-ray diffraction (K3[BP3O9(OH)3], monoclinic, C2/c (No. 15), a = 2454.6(8) pm, b = 736.3(2) pm, c = 1406.2(4) pm, beta = 118.35(2) degrees , Z = 8; Rb3[B2P3O11(OH)2], monoclinic, P2(1)/c (No. 14), a = 781.6(2) pm, b = 667.3(2) pm, c = 2424.8(5) pm, beta = 92.88(1) degrees , Z = 4). Both crystal structures comprise borophosphate chain anions. While for the rubidium compound a loop-branched chain motif is found as common for most of the chain anions in alkali metal borophosphates, the crystal structure of the potassium phase comprises the first open-branched chain with the highest phosphate content found so far in this group of compounds. Both chain anions are closely related to known anhydrous or hydrated phases, and the structural relations are discussed in terms of how the presence of OH groups and hydrogen bonds as well as number, charge, and size of charge balancing cations influence the 3D structural arrangement. The anionic entities are classified in terms of general principles of structural systematics for borophosphates.

Novel Mixed-Valence Heteropolyoxometalates: A Molybdenum Diphosphonate Anion [MoV7MoVIO16(O3PPhPO3H)4]3- and Its One- and Two-Dimensional Assemblies

A novel mixed-valence polyoxomolybdenum anion, [Mo(V)(7)Mo(VI)O(16)(O(3)PPhPO(3)H)(4)](3)(-), was synthesized hydrothermally from molybdenum oxide, molybdenum metal, boric and phosphoric acids, 1,2-phenyldiphosphonic acid, and imidazole (ImH) and was structurally characterized as an imidazolium salt (orthorhombic, Aba2; a = 16.674(4), b = 17.238(1), and c = 24.81(2) A). One- and two-dimensional structures of this anion and additional molybdenum diphosphonate linkers were assembled as well. They were structurally characterized as their pyridinium (pyH) salts (pyH)(4)[[Mo(V)(7)Mo(VI)O(16)(O(3)PPhPO(3))(2)(O(3)PPhPO(3)H)(2)][Mo(2)O(4)(OH)(HO(3)PPhPO(3)H)]].5H(2)O (monoclinic, P2(1)/c; a = 20.8506(9), b = 22.866(1), and c = 21.1403(9) A; beta = 118.7087(8) degrees ) and (pyH)(3)[[Mo(V)(7)Mo(VI)O(16)(O(3)PPhPO(3))(4)][Mo(2)O(2)(OH)(2)(HO(3)PPhPO(3)H)]].3H(2)O (orthorhombic, Pca2(1); a = 19.057(1), b = 20.402(2), and c = 20.660(2) A). The compounds were also characterized by IR spectroscopy and magnetic measurements.

[Mo5VMo7VIO30(BPO4)2(O3P-Ph)6]5-: a phenyl-substituted molybdenum(V/VI) boro-phosphate polyoxometalate

The title polyanion is the first hybrid borophosphate-phenylphosphonate polyoxometalate. It was structurally characterized as its imidazolium salt, (C(3)N(2)H(5))(5)[Mo(12)O(30)(BPO(4))(2)(O(3)P-Ph)(6)].H(2)O (monoclinic, P2(1)/c, a = 22.120(3) A, b = 13.042(2) A, and c = 32.632(4) A, beta = 101.293(3) degrees ), which was synthesized hydrothermally from imidazole, molybdenum oxide and metal, and boric, phosphoric, and phenylphosphonic acids. The anion is the second example of a new class of polyoxometalates that resemble Dawson anions but where the two pole caps of three edge-sharing MoO(6) octahedra in the latter are replaced by other units, in this case tetrahedral borate sharing corners with three phenylphosphonic groups, [(OB)(O(3)P-Ph)(3)]. The 12 molybdenum atoms forming the two equatorial belts of the cluster are of mixed-valence, five are Mo(V) and seven are Mo(VI), and the resulting five electrons are delocalized. Four of these electrons are paired according to the temperature dependence of the magnetic susceptibility. The new compound is soluble in a mixture of water and pyridine (in equal volumes) as well as in nitromethane, and the anions are intact in these solutions.

Synthesis and characterization of [Mo(7)O(16)(O(3)PCH(2)PO(3))(3)]:(8-) a mixed-valent polyoxomolybdenum diphosphonate anion with octahedrally and tetrahedrally coordinated molybdenum

Two new compounds containing the title diphosphono-polyoxometalate anion and diprotonated ethylenediamine (enH(2)) or piperazine (ppzH(2)) countercations have been hydrothermally synthesized and structurally characterized ((enH(2))(4)[Mo(7)O(16)(O(3)PCH(2)PO(3))(3)].7H(2)O, triclinic, P(-)1, Z = 2, a = 10.3455(7) A, b = 13.136(1) A, and c = 20.216(3) A, alpha = 93.247(6) degrees, beta = 96.434(6) degrees, and gamma = 111.900(6) degrees; (ppzH(2))(4)[Mo(7)O(16)(O(3)PCH(2)PO(3))(3)].8H(2)O, triclinic, P(-)1, Z = 2, a = 13.255(2) A, b = 13.638(2) A, and c = 16.874(4) A, alpha = 93.20(2) degrees, beta = 101.27(2) degrees, and gamma = 105.87(1) degrees). The anion is a ring of three pairs of edge-sharing octahedra of Mo(V)O(6) (with Mo(V)-Mo(V) bonds) that share corners with each other. The diphosphonate groups connect the pairs at the periphery. The ring is "capped" by a tetrahedron of Mo(VI)O(4). According to magnetic measurements, the compounds are diamagnetic.