Assembly of three supramolecular compounds based on [P2Mo5O23]6− and Ni(II) complexes

Three supramolecular compounds based on [P₂Mo₅O₂₃]^6? and Ni(II)–bim, [Ni(bim)₃]₃[P₂Mo₅O₂₃]·2H₂O (1), [Ni(Hbim)(bim)₂]₄[P₂Mo₅O₂₃]₂·3H₂O (2), and [Ni(bim)(Hbim)(phen)]₂[P₂Mo₅O₂₃]·7H₂O (3) (bim?=?2,2′-biimidazole, phen?=?1,10-phenanthroline), have been synthesized under hydrothermal conditions and characterized by elemental analysis, single-crystal X-ray diffraction, IR, and TG. All the compounds show 3-D supramolecular networks constructed from weak interactions among free Ni(II) complex, water, and oxygens of [P₂Mo₅O₂₃]^6?. Compound 3 represents the first supramolecular example integrating {Ni(bim)(Hbim)(phen)} with Strandberg-type phosphomolybdate. The compounds display good electrocatalytic activity to reduce hydrogen peroxide and intense fluorescence properties in solution at room temperature.     

Hydrothermal syntheses and crystal structures of two organic–inorganic hybrid molybdovanadates based on [V2Mo6(OH)2O24]4− and [VMo12O40]3− polyoxoanions

Two new organic–inorganic hybrid cobalt-molybdovanadates [Co(phen)₃]H₂[H₂V₂Mo₆O₂₆] · 7H₂O (1) and [Co(2,2′-bipy)₃][Na(H₂O)₇][VMo₁₂O₄₀] (2) have been hydrothermally synthesized and structurally characterized by elemental analyses, IR, UV, XPS spectroscopy, thermogravimetric (TG) analyses, and X-ray single crystal diffraction. The molecular structure of 1 consists of a [V₂Mo₆(OH)₂O₂₄]^4? polyoxoanion, a [Co(phen)₃]²⁺, two H⁺ and seven lattice water molecules. The structure of [V₂Mo₆(OH)₂O₂₄]^4? consists of six MoO₆ octahedra and two VO₄ tetrahedra; six MoO₆ octahedra are linked by edge-sharing oxygens forming a {Mo₆} ring, and two VO₄ tetrahedra cap opposite sides of the {Mo₆} ring. The molecular structural unit of 2 is constructed from a typical Keggin-type [VMo₁₂O₄₀]^3? polyoxoanion and a [Co(2,2′-bipy)₃]²⁺ cation and a Na⁺ countercation; Co²⁺ is coordinated by six nitrogens from three 2,2′-bipyridines forming a distorted octahedron.     

Hydrothermal syntheses and structural characterization of two new supramolecular compounds: (H2bbi)2[Mo8O26] and (H2bbi)2[SiW12O40]·2H2O [bbi = 1,1′-(1,4-butanediyl)bis(imidazole)]

Two new inorganic–organic hybrid supramolecular compounds based on imidazolium and POMs formulated as (H₂bbi)₂[Mo₈O₂₆] (1) and (H₂bbi)₂[SiW₁₂O₄₀]·2H₂O (2) [bbi = 1,1′-(1,4-butanediyl)bis(imidazole)] have been prepared under hydrothermal conditions and characterized by elemental analyses, IR and single-crystal X-ray diffraction analyses. The two compounds consist of protonated bbis together with POMs. [Mo₈O₂₆]^4? and [SiW₁₂O₄₀]^4? are linked through H₂bbi into a three-dimensional (3D) network via hydrogen bonds, respectively. Compound 1 is the first example of 3D two-fold interpenetrating hydrogen bond-supported supramolecular assembly from octamolybdate one-dimensional (1D) chain and imidazolium. The fascinating structural feature of compound 2 is that the anions and the protonated bbi ligands formed a 3D (4, 8) supramolecular network by hydrogen bonds. Compound 2 has been used as a solid bulk-modifier to fabricate three-dimensional bulk-modified carbon paste electrode (CPE) by direct mixing. The electrochemical behavior and electrocatalysis of compound 2 modified CPE (2-CPE) have been studied.     

Hydrothermal synthesis,crystal structure and fluorescence of a 3D organic–inorganic hybrid coordination network [CuI(4,4′-bipy)]4[ δ -Mo8O26] exhibiting an interesting polymorphism

A new three-dimensional (3D) extended solid [Cu^I(4,4′-bipy)]₄[δ-Mo₈O₂₆] (1) built on {Cu(4,4′-bipy)}⁺ (bipy?=?bipyridine) and isopolymolybdate anion [δ-Mo₈O₂₆]^4? has been synthesized and characterized by elemental analysis, IR, TG, X-ray powder diffraction and single-crystal X-ray diffraction analysis. Compound 1 shows six coppers bonded to [δ-Mo₈O₂₆]^4? to form inorganic planes which are linked by 4,4′-bipy into a 3D network, the first example of [δ-Mo₈O₂₆]^4? six-connected linkage based on an organic-inorganic coordination polymer. A polymorphism of compound 1 was found which has an identical molecular formula but absolutely different structure. The influence of the synthesis conditions of 1 has been studied. Furthermore, the fluorescence of 1 is reported.     

Three 2,2′-biimidazole transition metal complex-supported octamolybdates derived from hexamolybdochromate

Three octamolybdate compounds, namely [Cu(H₂biim)₂]₂[β-Mo₈O₂₆{Cu(H₂biim)₂}₂][β-Mo₈O₂₆] (1), [{Fe(H₂biim)₂(Hbiim)}₂(γ-Mo₈O₂₆)]·5H₂O (2), and [{Co(H₂biim)₂(Hbiim)}₂(γ-H₂Mo₈O₂₆)]·5 H₂O (3) (H₂biim = 2,2′-biimidazole) have been hydrothermally synthesized from the reaction of mixtures of hexamolybdochromate ({CrMo₆}), transition metal, and H₂biim in acetate buffer solution, and characterized by physico-chemical and spectroscopic methods. They represent the first examples of the conversion of hexamolybdochromate to octamolybdate. Single-crystal X-ray diffraction analysis reveals that compound 1 is composed of a β-[Mo₈O₂₆]⁴⁻ polyoxoanion bi-supported by two [Cu(H₂biim)₂]²⁺ complex cations, an isolated β-[Mo₈O₂₆]⁴⁻ anion, and two [Cu(H₂biim)₂]²⁺ complex cations. The copper complex cations are situated at two different sites and associate with β-[Mo₈O₂₆]⁴⁻ anions to give 2D layers, which are further packed into a 3D framework via strong hydrogen bonding interactions. Compounds 2 and 3 are isostructural, and contain a γ-[Mo₈O₂₆N₂] unit and two symmetrical {M(H₂biim)₂(Hbiim)} (M=Fe or Co) fragments grafted onto the polyoxoanion through Mo–N bonds. The two compounds also exhibit 3D supramolecular frameworks involving hydrogen bonding interactions.     

Two organic–inorganic hybrid compounds constructed from [PMoV1MoVI7VIV2VV4O42]4− and different transition metal fragments

Two new organic–inorganic hybrid compounds, [Cu(phen)(prz)]₂[PMo^V₁Mo^VI₇V^IV₂V^V₄O₄₂]·4H₂O (1) and [Ag₂(phen)₄]₂[PMo^V₁Mo^VI₇V^IV₂V^V₄O₄₂] (2) (phen = 1,10-phenanthroline, prz = pyrazine), have been synthesized and characterized by IR, XPS, XRD, UV–vis, fluorescent spectra analyses, elemental analyses, X-ray diffraction analyses, TG analyses, and cyclic voltammetric measurements. Both compounds are formed by Keggin POM cores and transition metal fragments. Compound 1 exhibits an unprecedented 1-D chain structure constructed from [PMo^V₁Mo^VI₇V^IV₂V^V₄O₄₂]^4? and [Cu(phen)(prz)]²⁺ in the –A–B↑–C–B↓– linking mode. Compound 2 shows a supramolecular structure formed by [PMo^V₁Mo^VI₇V^IV₂V^V₄O₄₂]^4? and [Ag₂(phen)₄]²⁺.     

Two-dimensional layer polyoxometalate-based inorganic metal–organic hybrid supramolecular networks woven by Cu ··· Opolyoxoanion short contact weak interactions

Two polyoxometalate-based inorganic metal-organic hybrid supramolecular complexes [Cu(2,2′-bpy)₂]₂[V^IV ₂Mo^V ₅Mo^VI ₇O₃₈(PO₄)] (1) (2,2′-bpy?=?2,2′-bipyridine) and [Cu(2,2′-bpy)₂]₂[Mo^VMo^VI ₁₁O₃₆(PO₄)]?·?3H₂O (2), have been hydrothermally prepared and structurally characterized by single-crystal X-ray diffraction. Both complexes are constructed from polyoxoanions (the bivanadyl capped α-Keggin polymolybdate anion [V^IV ₂Mo^V ₅Mo^VI ₇O₃₈(PO₄)]^4? for 1 and the reduced 12-molybdophosphate anion [Mo^VMo^VI ₁₁O₃₆(PO₄)]^4? for 2) and copper(II) complex cations [Cu(2,2′-bpy)₂]²⁺, forming two-dimensional (2D) layer network structures, in which the polyoxoanion and the complex fragment cation connect with each other through Cu?···?O_polyoxoanion short contact weak interactions, which mediate ferromagnetic interaction.     

Hydrothermal synthesis and crystal structure of a 1-D compound constructed from molybdovanadate clusters [V2Mo6O26]6− and copper complexes

A 1-D organic–inorganic hybrid compound, {Cu(en)₂}[V₂Mo₆O₂₆{Cu(en)₂}₂] · 4H₂O [en = ethylenediamine] (1), was hydrothermally synthesized and characterized by IR, UV spectroscopy, TG/DTA analyses, and single crystal X-ray diffraction. The X-ray crystallography analysis reveals an infinitely extended 1-D chain constructed from a molybdovanadate cluster [V₂Mo₆O₂₆]^6? as a building unit, two copper(II) complex fragments, {Cu(en)₂}²⁺, as attached groups and a copper(II) fragment, {Cu(en)₂}²⁺, as a bridging group. Each chain links to adjacent chains through weaker secondary Cu–O interactions forming an interesting 3-D supramolecular architecture.     

Synthesis and Characterization of a Novel Organic/Inorganic Hybrid Based on Octamolybdates and Benzimidazole Molecules [Hbenzimi]4 [(benzimi)2Mo8O26] · 2H2O (benzimi?=?benzimidazole)

A novel organic/inorganic compound [Hbenzimi]₄[(benzimi)₂Mo₈O₂₆] · 2H₂O (1) has been prepared hydrothermally and characterized by elemental analyses, i.r., x.p.s., t.g. and single crystal X-ray diffraction. The single crystal X-ray diffraction analysis reveals that compound (1) consists of the [Mo₈O₂₆]⁴⁻ cluster as the structural motif covalently linked by benzimidazole molecules and protonated benzimidazole molecules as charge compensation cations. It is interesting that the benzimidazole molecules were synthesized from 1,2-phenylenediamine and oxalic acid. The [Mo₈O₂₆]⁴⁻ polyoxoanions and organic ligands in compound (1) interact with each other via extensive hydrogen bonds to form a three-dimensional supramolecular framework.     

Three pure inorganic materials based on Strandberg-type phosphomolybdate and different transition metal linkers

Abstract

Three inorganic materials based on Strandberg polyoxoanion, Na₁₀[Ag(P₂Mo₅O₂₃)]₂·8H₂O (1), Na₈[{Cu(H₂O)₄}(HP₂Mo₅O₂₃)₂]·8H₂O (2), and Na₈[{Co(H₂O)₄}(HP₂Mo₅O₂₃)₂]·6H₂O (3), were hydrothermally synthesized and characterized by elemental analyses, IR, TG, and single crystal X-ray diffraction analyses. The compounds are based on the [P₂Mo₅O₂₃]^6? cluster and transition metal linkers. Compound 1 is a 1-D wave-like chain connected by Ag⁺ bridges. Compounds 2 and 3 are isostructural dimers bonded by {Cu(H₂O)₄} or {Co(H₂O)₄} linkers. The 1-D chain and dimeric clusters of 1-3 are further extended to 3-D supramolecular networks via hydrogen bonds and supramolecular interactions. Channels with different sizes are observed in 1-3, in which isolated Na⁺ and lattice water molecule fill the channels via intermolecular interactions. Weak interactions play important roles in stabilizing the three 3-D networks. Electrochemical and electrocatalytic properties of 1-3 have been investigated.     

1D Polyoxometalate‐based Inorganic‐Organic Hybrid Derived from ß‐Octamolybdate — Synthesis and Crystal Structure of [CoII(2, 2′‐bipy)2]2[Mo8O26]

A polyoxometalate‐based inorganic–organic hybrid compound [Co^II(2, 2′‐bpy)₂]₂[Mo₈O₂₆] ( 1 ) was synthesized by hydrothermal methods and structurally characterized by IR spectrum, TG analysis and X‐ray diffraction. The compound crystallizes in the monoclinic system, space group P2₁/n, a = 10.0681(2), b = 16.4467(2), c = 15.7838(3) Å, β = 100.046(1)°, V = 2573.52(8) ų, Z = 2. The structure of 1 is built up from β‐[Mo₈O₂₆]^4? subunits covalently linked via [Co^II(2, 2′‐bpy)₂]²⁺ fragments into a infinite 1D {[Co^II(2, 2′‐bpy)₂]₂[Mo₈O₂₆]}_∞ polymer.     

The rigid isomeric 5-(x-pyridyl)-1H-tetrazole ligands-directed various isopolymolybdate-based compounds: assembly,structures, and properties

Two new isopolymolybdate-based metal–organic complexes, [Cu₂(2-ptz)₂(Mo₄O₁₄)_0.5] (1) and [Cu₃(OH)₂(3-ptz)₄(γ-H₄Mo₈O₂₆)(H₂O)₄]·10H₂O (2) (2-ptzH = 5-(2-pyridyl)-1H-tetrazole, 3-ptzH = 5-(3-pyridyl)-1H-tetrazole), constructed from isomeric ligands with different N-donor sites were synthesized under hydrothermal conditions. In 1, each [Mo₄O₁₄]^4? cluster connected with six neighboring [Mo₄O₁₄]^4? clusters through six binuclear [Cu₂(2-ptz)₂]²⁺ subunits to yield a 2-D layer. In 2, bidentate inorganic [Mo₈O₂₆]^4? anions link the trinuclear [Cu₃(OH)₂(3-ptz)₄] clusters to construct a 1-D chain. Adjacent chains connect through Mo–N bonds between the [Mo₈O₂₆]^4? anions and pyridyl groups from the trinuclear clusters to form a 2-D layer. The effect of the N-donor sites of the rigid isomeric ligands on the structures of 1 and 2 was discussed. The electrochemical properties and photocatalytic activities of 1 and 2 have also been studied.     

A new hybrid material constructed from octamolybdate anion and neutral dinuclear copper units

A new organic–inorganic hybrid material constructed from octamolybdate anion and neutral dinuclear copper(I) units, H₄{[Cu₂(ophen)₂]₂[Mo₈O₂₆]}[Cu₂(ophen)₂] · H₂O (1) (Hophen =2-hydroxy-1,10-phenanthroline), has been prepared under hydrothermal condition and characterized by elemental analysis, IR, XPS, TGA and single-crystal X-ray diffraction. Compound 1 crystallizes in the triclinic system, space group P 1, with a = 9.9091(8), b = 13.3981(8), c = 14.8266(10) Å, α = 84.6310(10), β = 83.0620(10)°, γ = 77.7800(10), V = 1905.0(2) ų, Z = 1. Compound 1 contains a centrosymmetric polyoxoanion {[Cu₂(ophen)₂]₂[Mo₈O₂₆]}^4?, in which the β-[Mo₈O₂₆]^4? is bisupported by two copper(I) coordination groups through the terminal oxygen atoms. The discrete molecules of 1 are extended into a 3-D supramolecular array through C–H ··· O hydrogen bonds and strong aromatic π–π stacking contacts.     

Hydrothermal synthesis and characterization of two novel tungstovanadophosphate derivatives

Two novel tungstovanadophosphate derivatives, namely [Fe(phen)₃]₂[PW₈^VIV^VV₅^IVO₄₂] · H₂O (1) and [Fe(phen)₃]₂[PW₉V₃O₄₀] (2), were synthesized under hydrothermal conditions, and characterized by elemental analysis, IR, ESR, XPS, TGA, and single-crystal X-ray diffraction analysis. The crystal structure analyses reveal that the ‘mixed-addenda’ Keggin polyoxoanion in 1 is decorated with VO²⁺ units, such that four V atoms are disordered over eight metal sites; the anion in compound 2 has a typical Keggin structure with three V atoms disordered over 12 metal sites. The two compounds are ionic crystals with slightly different packing modes for the polyoxoanions and [Fe(phen)₃]³⁺ cations. π–π stacking interactions between phen molecules, weak hydrogen bonding interactions between phen ligands and polyoxoanions, and electrostatic forces lead to an extended 3D supramolecular framework. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

A metal-oxo cluster-supported transition metal complex: synthesis,structure and properties of [Cu(phen)2]2[{Cu(phen)}2Mo8O26]·H2O

[Cu(phen)₂]₂[{Cu(phen)}₂Mo₈O₂₆]·H₂O has been synthesized from MoO₃, H₂MoO₄, Cu(Ac)₂·H₂O and 1,10-phenanthroline in aqueous solution using the hydrothermal method and characterized by single-crystal X-ray structure analysis. The title compound consists of a centrometric β-octamolybdate-supported complex anion [{Cu(phen)}₂Mo₈O₂₆]²⁻, two bis-phenanthroline Cu(I) cations, and one water molecule of crystallization.     

Hydrothermal synthesis and crystal structure of (H2bpp)3[Mo5P2O23]·H2O: a twofold interpenetrating 3D supramolecular architecture constructed of Standberg-type polyoxometalate

A novel three-dimensional (3D) supramolecular assembly of Standberg-type polyoxometalate and flexible organic molecule (H₂bpp)₃[Mo₅P₂O₂₃]·H₂O (1) [bpp = 1,3-bis(4-pyridyl)propane] has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction, IR spectra, elemental analysis and thermogravimetric analysis (TGA). X-ray analyses show that compound 1 represent a twofold interpenetrating 3D supramolecular architecture constructed of Standberg-type polyoxometalate and bpp molecular through the hydrogen bonds as well as electrostatic interactions.     

Syntheses and crystal structures of two 2D coordination polymers of cobalt(II) and nickel(II) with the Malonate Dianion Ligand

Two 2D complexes, [Co(mal)(phen)(H₂O)₂] (1) and [Ni(mal)(phen)(H₂O)₂] (2) (mal?=?malonate dianion; phen?=?1,10-phenanthroline), have been synthesized by the reaction of Co(ClO₄)₂·6H₂O and Ni(ClO₄)₂·6H₂O with disodium malonate and 1,10-phenanthroline in MeOH/H₂O solution. Their crystal structures have been determined by X-ray diffraction. The structures of Complexes 1 and 2 show that each metal ion is coordinated by one 1,10-phenanthroline, two water molecules and a malonate ligand forming a distorted octahedral environment and each mononuclear fragment forms a 2D supramolecular network through H-bonding interactions.     

Synthesis,structural characterization,and properties of two new polyoxovanadates based on decavanadate [V10O28]6−

Two new decavanadate metal compounds, [Co(pyim)₃]₂[V₁₀O₂₈]·7H₂O (1) and [Ni(pyim)₃]₂[H₂V₁₀O₂₈]·4H₂O (2) (pyim?=?2-(2-pyridyl)-imidazole), have been synthesized under hydrothermal conditions and characterized by elemental analysis, single-crystal X-ray diffraction analysis, infrared spectra, powder X-ray diffraction analysis, and thermogravimetric analysis. Crystallographic analysis reveals that 1 is constructed from [V₁₀O₂₈]^6?, metal cation [Co(pyim)₃]³⁺, and water. [V₁₀O₂₈]^6? clusters are connected by waters through O–H?O hydrogen bonds to form a sheet structure which is further connected by N–H?O hydrogen bonds to form a 3-D supermolecular framework. In 2, although [Ni(pyim)₃]²⁺ is similar to [Co(pyim)₃]³⁺ in 1, the M?O cluster anion is protonated [H₂V₁₀O₂₈]^4?.     

Two α-metatungstate compounds containing supramolecular helical chains

[Co(bipy)₃]₃[{Co(bipy)₂(H₂O)}₂{H₃W₁₂O₄₀}₂] · H₂O (1) and [H₂bipy]_0.5[{Cu(bipy)₂}₂{H₃W₁₂O₄₀}] · H₂O (2) (bipy = 2,2′-pyridine) have been hydrothermally synthesized and characterized by single-crystal X-ray diffraction, elemental analyses, IR spectra, and TG analyses. In 1, there exist supramolecular left/right-helical chains constructed by [Co1(bipy)₃]²⁺ and these chains perpendicularly interact with a series of parallel POM double-chains composed of [{Co(bipy)₂(H₂O)}₂{H₃W₁₂O₄₀}₂]^6? anions and [Co2(bipy)₃]²⁺ cations forming a 3-D supramolecular network. In 2, there also exist supramolecular left-/right-helical chains constructed by [{Cu(bipy)₂}₂{H₃W₁₂O₄₀}]^? fragments. Furthermore, these left-/right-helical chains are linked together via H-bonds forming interesting enantiomorphous chiral layers. Electrochemical properties of these compounds have been studied.     

Effect of the central metal on coordination of 1,10-phenanthroline-5,6-dione in Keggin-based hybrid compounds

Two new Keggin-based hybrid compounds, [Cu₂(pdon)₃][PMo^VI ₁₁Mo^VO₄₀]·3H₂O (1) and [Mn₂Cl(H₂O)₂(pdon)₄][PMo₁₂O₄₀]·2H₂O (2) (pdon = l, l0-phenanthroline-5,6-dione) (pdon), were synthesized under hydrothermal conditions. By using different metal ions and tuning the ratio of metal to ligand, pdon shows different coordination modes. In compound 1, pdon with three kinds of coordination modes link Cu^II ions to form a 1D wave chain and Keggin-type polyanions [PMo^VI ₁₁Mo^VO₄₀]^4? fringe this 1D chain; hydrogen bonding interactions extend these 1D chains into a 2D supramolecular network. Compound 2 exhibits a discrete structure, in which pdon shows a single chelating coordination. Electrochemical properties of the title compounds have been investigated.