Supramolecular assembly based on a heteropolyanion: synthesis and crystal structure of Na<SUB>3</SUB>(H<SUB>2</SUB>O)<SUB>6</SUB>[Al(OH)<SUB>6</SUB>Mo<SUB>6</SUB>O<SUB>18</SUB>]&#183;2H<SUB>2</SUB>O

Synthesis and structural characterization of a polyoxometalate compound Na3(H2O)6 [Al(OH)6Mo6O18]&#183;2H2O (1) have been described. Compound1 exhibits three-dimensional network structure in the solid state, which is assembled by Anderson-type heteropolyanions, [Al(OH)6Mo6O18]n3n- , as building blocks sharing sodium cations.1 possesses "sinuous" channels occupied by supramolecular water dimers as guests. Anderson anions, sodium-coordinated water and crystal water are additionally involved in an intricate hydrogen-bonding network in the crystal of 1

Polyoxometalates: toward new materials

This article describes an account of some of our polyoxometalate (POM)-based research, we have been doing in our laboratory last several years. There are several well-defined POM cluster anions, that are structurally characterized. We have chosen Anderson-type of heteropolyanion [Al(OH)6Mo6O18]3- and explored its linking propensity in different dimensions using 's', 'd' and 'f' block elements as linkers.We have demonstrated how a lanthanide linker provides a new pathway in forming a two-dimensional linked {As8V14} system [{Ln(H2O)6}2As8V14O42(SO3)]n · 8nH2O, that is derived from discrete {As8V14} cluster containing compound (NH4)6[As8V14O42(SO3)]. A polyoxometalate compound has been described in which a reduced tungstovanadate-heteropolyanion clusters get linked via capped V = O groups into one-dimensional chains. All these systems have already been reported elsewhere. The last portion of this article will be described by a new system [3-ampH]6[V10O28] · 2H2O having discrete molecular structure and extended supramolecular structure

Inclusion of a Cu<SUP>2+</SUP> ion by a large-cavity crown ether dibenzo-24-crown-8 through supramolecular interactions

A supramolecular copper-aqua-crown ether complex, [CuII(H2O)4(dibenzo-24-crown-8]2+ (1c) is stabilized with a Lindqvist-type polyoxometalate anion, [MoVI6O19]2- (1a), in an ion-pair compound [CuII(H2O)4(dibenzo-24-crown-8][MoVI6O19] = [1c][1a] = 1. In the crystal, 1c and 1a assemble to a chainlike structure in which each polyoxoanion 1a is sandwiched by two 1c cations. 1c is a structurally characterized dibenzo-24-crown-8 (a larger-cavity crown ether) supramolecular complex that shows encapsulation of a small cation at the center of its internal cavity, and compound 1 represents a unique example of a first-row transition metal-crown ether inclusion complex that interacts with a polyoxometalate anion

Fivefold coordination of a Cu<SUP>II</SUP>-aqua ion: a supramolecular sandwich consisting of two crown ether molecules and a trigonal-bipyramidal [Cu(H<SUB>2</SUB>O)<SUB>5</SUB>]<SUP>2+</SUP> complex

Copper crowned: A trigonal-bipyramidal [Cu(H<SUB>2</SUB>O)<SUB>5</SUB>]<SUP>2+</SUP> ion, which is inserted between two crown ether molecules ([18]crown-6) to form a unique supramolecular sandwich, [Cu(H<SUB>2</SUB>O)<SUB>5</SUB>([18]crown-6)<SUB>2</SUB>]<SUP>2+</SUP> (see picture), has been characterized unambiguously by single-crystal X-ray diffraction. Isopolyanions, [Mo<SUB>6</SUB>O<SUB>19</SUB>]<SUP>2-</SUP>, facilitate the formation of this new structure

Synthesis and characterization of a reduced heteropoly-tungstovanadate: (NH<SUB>4</SUB>)<SUB>7</SUB>[V<SUP>v</SUP>O<SUB>4</SUB>W<SUB>10</SUB><SUP>VI</SUP>V<SUB>2</SUB><SUP>IV</SUP>O<SUB>36</SUB>]·ca. 22H<SUB>2</SUB>O

The compound ((NH4)7[VvO4W10VIV2IVO36]·ca. 22H2O (1) has been synthesized from an aqueous ammonium acetate buffer (pH 4) containing sodium vanadate, sodium rungstate_and sodium dithionite. Compound (1) crystallizes in a cubic space group Fm 3̅, with α = 22·2001(6) Å and Z = 8. The anion [VvO4W10VIV 2IVO36]7- is a typical Keggin type structure with VVO4 as the central tetrahedron. (1) has further been characterized by elemental analyses, redox titration, IR, EPR, and electronic spectroscopy and room temperature magnetic moment measurement

Polyoxometalate-supported transition metal complexes and their charge complementarity: synthesis and characterization of [M(OH)<SUB>6</SUB>Mo<SUB>6</SUB>O<SUB>18</SUB> {Cu(Phen)(H<SUB>2</SUB>O)<SUB>2</SUB>}<SUB>2</SUB>][M(OH)<SUB>6</SUB>Mo<SUB>6</SUB>O<SUB>18</SUB>{Cu(Phen)(H<SUB>2</SUB>O) Cl}2]·5H<SUB>2</SUB>O (M = Al<SUP>3+</SUP>, Cr<SUP>3+</SUP>)

Two Anderson-type heteropolyanion-supported copper phenanthroline complexes, [Al(OH)6Mo6O18{Cu(phen)(H2O)2}2]1+ (1c) and [Al(OH)6Mo6O18{Cu(phen)(H2O)Cl}2]1- (1a) complement their charges in one of the title compounds [Al(OH)6Mo6O18{Cu(phen)(H2O)2}2][Al(OH)6Mo6O18{Cu(phen)(H2O)Cl}2]·5H2O = [1c][1a]·5 H2O = 1. Similar charge complementarity exists in the chromium analogue, [Cr(OH)6Mo6O18{Cu(phen)(H2O)2}2][Cr(OH)6Mo6O18{Cu(phen)(H2O)Cl}2]·5 H2O = [2c][2a]·5 H2O = 2. The chloride coordination to copper centers of 1a and 2a makes the charge difference. In both compounds, the geometries around copper centers are distorted square pyramidal and those around aluminum/chromium centers are distorted octahedral. Three lattice waters, from the formation of intermolecular O-H·····O hydrogen bonds, have been shown to self-assemble into an "acyclic water trimer" in the crystals of both 1 and 2. The title compounds have been synthesized in a simple one pot aqueous wet-synthesis consisting of aluminum/chromium chloride, sodium molybdate, copper nitrate, phenanthroline, and hydrochloric acid, and characterized by elemental analyses, EDAX, IR, diffuse reflectance, EPR, TGA, and single-crystal X-ray diffraction. Both compounds crystallize in the triclinic space group P↑ . Crystal data for 1: α = 10.7618(6), b = 15.0238(8), c = 15.6648(8) Å, α = 65.4570(10), β = 83.4420(10), γ = 71.3230(10)°, V = 2182.1(2) Å3. Crystal data for 2: a = 10.8867(5), b = 15.2504(7), c = 15.7022(7) Å, α = 64.9850(10), β = 83.0430(10), γ = 71.1570(10)°, V = 2235.47(18) Å3. In the electronic reflectance spectra, compounds 1 and 2 exhibit a broad d-d band at ~700 nm, which is a considerable shift with respect to the value of 650-660 nm for a square-pyramidal [Cu(phen)2L] complex, indicating the coordination of [M(OH)6Mo6O18]3- POM anions (as a ligand) to the monophenanthroline copper complexes to form POM-supported copper complexes 1c, 1a, 2c, and 2a. The ESR spectrum of compound 1 shows a typical axial signal for a Cu2+ (d9) system, and that of compound 2, containing both chromium(III) and copper(II) ions, may reveal a zero-field-splitting of the central Cr3+ ion of the Anderson anion, [Cr(OH)6Mo6O18]3-, with an intense peak for the Cu2+ ion

Formation of a spiral-shaped inorganic-organic hybrid chain,[Cu<SUP>II</SUP> (2, 2'-bipy)(H<SUB>2</SUB>O)<SUB>2</SUB>Al(OH)<SUB>6</SUB>Mo<SUB>6</SUB>O<SUB>18</SUB>]<SUB>n</SUB><SUP>n-</SUP>: influence of intra- and interchain supramolecular interactions

A novel chainlike coordination polymer [CuII(2,2'-bipy)(H2O)2Al(OH)6Mo6O18]nn-, formed from a heteropolyanion [Al(OH)6Mo6O18]3- as a building unit and a copper(II) complex fragment, [CuII(2,2'-bipy)(H2O)2]2+, as a linker, provides the first example of an extended structure based on an Anderson type of polyanion and a transition metal complex with organic ligand. The intra- and interchain O-H&#183;&#183;&#183;O hydrogen-bonding interactions are seemingly responsible for the spiral shape of this chain. Crystal data: triclinic space group P&#x2191;, a = 11.2253(18) &#197;, b = 14.5194(17) &#197;, c = 15.2672(10) &#197;, &#945; = 112.191(8)&#176;, &#946; = 106.693(9)&#176;, &#947; = 93.916(13)&#176;, and Z = 2c

The first one-dimensional heteropoly tungstovanadate coordination polymer: [(V<SUP>V</SUP>O<SUB>4</SUB>)W<SUP>VI</SUP><SUB>8</SUB>M<SUB>4</SUB>O<SUB>36</SUB>(V<SUP>IV</SUP>O)<SUB>2</SUB>]<SUP>n-</SUP> (M=0.71V<SUP>IV</SUP>+0.29W<SUP>VI</SUP>, n=4.68)

An aqueous ammonium acetate buffer solution (pH 4) containing vanadate, tungstate and dithionite ions, on heating at 100 &#176;C for 1 h yields one-dimensional polyoxometalate chain compound (NH<SUB>4</SUB>)<SUB>4.68</SUB>[(V<SUP>V</SUP>O<SUB>4</SUB>)W<SUP>VI</SUP><SUB>8</SUB>M<SUB>4</SUB>O<SUB>36</SUB>(V<SUP>IV</SUP>O)<SUB>2</SUB>]&#183;12H<SUB>2</SUB>O (M=0.71V<SUP>IV</SUP>+0.29W<SUP>VI</SUP>) 1, which is characterized by single-crystal X-ray structure determination, redox titration, and IR spectroscopic studies. Crystallographic data for 1, H<SUB>42.72</SUB>N4<SUB>.68</SUB>O<SUB>54</SUB>V<SUB>5.8</SUB>4W<SUB>9.16</SUB>, tetragonal, space group 1 4, a=15.8132(5), c=11.1114(5) &#197;, Z=2, V=2778.5(2) &#197;<SUP>3</SUP>

Stabilization of a new type of water octamer in the crystalline hydrate of an inorganic-organic hybrid material: synthesis and characterization of [{Cu(phen)(H<SUB>2</SUB>O)<SUB>2</SUB>}<SUB>2</SUB>(Mo<SUB>8</SUB>O<SUB>26</SUB>)] · 8H<SUB>2</SUB>O

A supramolecular water octamer, (H<SUB>2</SUB>O)<SUB>8</SUB> has been crystallographically observed to be formed in the crystalline hydrate of an inorganic-organic hybrid compound [{Cu(phen)(H<SUB>2</SUB>O)<SUB>2</SUB>}<SUB>2</SUB>(Mo<SUB>8</SUB>O<SUB>26</SUB>)] · 8H<SUB>2</SUB>O (1). Compound 1 consists of an octamolybdate isopolyanion, two mono(phenanthroline)copper(II) complex cations and eight lattice water molecules per formula unit. The formation of such unusual (H<SUB>2</SUB>O)<SUB>8</SUB> cluster is believed to be stabilized by its non-covalent O-H···O type hydrogen bonding interactions with the isopolyanion in the solid state. To the best of our knowledge, this is the first instance of a discrete water octamer found in a polyoxometalate-based system

Identification of a near-linear supramolecular water dimer,(H<SUB>2</SUB>O)<SUB>2</SUB>, in the channel of an inorganic framework material

Supramolecular water dimer, (H2O)2, is fundamentally important. During the course of our work on polyoxometalates, we have been able to identify the existence of hydrogen-bonded, near-linear water dimers in the "sinuous" channels of an inorganic framework material, Na3n(H2O)6n[Al(OH)6Mo6O18]n&#183;2nH2O, 1. The three-dimensional network structure of 1 in the solid state is assembled by the Anderson type of heteropolyanions as building blocks sharing sodium cations. Vibrational spectroscopy, X-ray powder diffraction technique, TG-DSC analyses, and single-crystal X-ray structure analysis have characterized this host-guest system, 1. Crystal data for 1: triclinic space group P&#x2191;, a = 12.0618 (3) &#197;, b = 13.1570 (4) &#197;, c = 14.1563 (4) &#197;, &#945; = 80.7850 (10)&#176;, &#946; = 75.2660 (10)&#176;, &#947; = 68.9210 (10)&#176;, and Z = 3