Sandwich-type polyoxotungstate hybrids decorated by nickel-aromatic amine complexes

Three new sandwich-type polyoxotungstates (POTs) decorated by nickel-2,2′-bpy complexes [{Ni(2,2′-bpy)₂(H₂O)}₂{Ni(2,2′-bpy)}₂ {Ni₄(H₂O)₂(B-α-XW₉O₃₄)₂}]ⁿ⁻ (X=P^V, n=4 for 1; X=As^V, n=4 for 2; X=Ge^IV, n=4 for 3) (2,2′-bpy=2,2′-bipyridine) were successfully synthesized under hydrothermal conditions and structurally characterized by elemental analyses, IR spectroscopy, single-crystal X-ray diffraction, and magnetic properties. Single-crystal structural analyses indicate that 1 and 2 are isostructural and both crystallize in the monoclinic space group C2/c, whereas 3 belongs to the triclinic space group . To our knowledge, 1, 2 and 3 represent rare examples of the organic-inorganic hybrid sandwich-type polyoxometalates functionalized by multiple nickel-aromatic amine complexes. Magnetic measurements of 1 exhibit the presence of ferromagnetic interactions within the rhombic tetranuclear-Ni^II cluster.     

Hydrothermal Synthesis and Structural Characterization of Three One-Dimensional Heteropolytungstates Formed by Mono-CopperII-Substituted Dawson or Keggin Cluster Units

Abstract  Reactions of monovacant Dawson-/Keggin-polyoxoanions, formed in situ from trivacant Dawson-/Keggin-precursors, with copper complexes under hydrothermal conditions lead to three inorganic–organic hybrid polyoxotungstates [Cu(en)₂(H₂O)]₂{[Cu(en)₂(H₂O)]₂[Cu(en)₂]₄[Cu(en)₂][α₂-P₂W₁₇CuO₆₁]₂}·(OH)₂·12H₂O (1), [Cu(dap)₂][Cu(dap)₂(H₂O)]₂[α-PW₁₁CuO₃₉]·(OH)·2H₂O (2) and (H₂en)₂[α-PW₁₁CuO₃₉][Cu(en)₂(H₂O)₂]_0.5·1.5H₂O (3) (en = ethylenediamine and dap = 1,2-diaminopropane). X-ray structural analyses demonstrate that 1 exhibits the first zigzag 1-D chain arrangement constructed from mono-copper^II-substituted Dawson dimeric polyoxoanions [α₂-P₂W₁₇CuO₆₁]₂¹⁶⁻ linked by [Cu(en)₂]²⁺ bridges, whereas 2 and 3 display 1-D linear chain architectures made up of mono-copper^II-substituted Keggin polyoxoanions [α-PCuW₁₁O₃₉]⁵⁻ linked together via corner-sharing MO₆ octahedra (M = Cu or W). Graphical Abstract  Reactions of monovacant Dawson or Keggin polyoxoanions with copper complexes under hydrothermal conditions lead to three novel 1-D chain-like inorganic- organic hybrid polyoxotungstates.      

Hydrothermal Syntheses and Characterization of Two 1D Chain Complexes and Tetra-capped Keggin Clusters

Two new compounds, [Ni(en)₂]{[Ni(en)₂]₂[Mo^VI₆Mo^V₂V^IV₈O₄₀(SiO₄)]}[(NH₂)₂(C₂H₄)₂NH]·2H₂O(1) and [Ni(en)₂]{[Ni(en)₂]₂[Mo^VI₅Mo^V₃V^IV₈O₄₀(VO₄)]}(en)·H₂O(2)(en=ethylenediamine), have been hydrothermally synthesized and characterized by elemental analysis, infrared(IR), X-ray photoelectron spectroscopy(XPS), electron spin-resonance(ESR) and thermogravimetric(TG) analysis and single-crystal X-ray diffraction(XRD) analysis. Both the compounds exhibit a 1D chain composed of bi-supporting tetra-capped Keggin clusters and nickle coordination fragments. The 1D chains are further assembled into a 3D supramolecular network with different packing modes via hydrogen bonds. The magnetic susceptibility of compound 1 demonstrates the presence of antiferromagnetic interactions.     

Hydrothermal synthesis and structural characterization of two 1-D and 2-D Dawson-based phosphotungstates

Two new Dawson-based phosphotungstates (H₂en)_0.5H[Cu(en)₂(H₂O)]₂{[Cu(en)₂](α₁-P₂W₁₇CuO₆₁)}·8H₂O (1) (en=ethylenediamine) and [4,4′-H₂bpy]₂{[Cu(4,4′-bpy)₃][Cu(4,4′-bpy)₄(H₂O)₂]₂[Cu(4,4′-bpy)][α-P₂W₁₈O₆₂]₂}·6H₂O (2) (4,4′-bpy=4,4′-bipyridine) have been hydrothermally synthesized and structurally characterized. 1 crystallizes in the triclinic space group P−1 with a=11.7626(17), b=13.246(2), c=29.350(5) Å, α=87.355(5), β=79.583(5), γ=66.993(3)°, V=4138.3(11) Å³, Z=2, GOF=1.089, R₁=0.0563 and wR₂=0.1505, whereas 2 belongs to the orthorhombic space group Iba2 with a=22.277(8), b=47.04(2), c=22.153(8) Å, V=23215(17) Å³, Z=4, GOF=1.051, R₁=0.0627 and wR₂=0.1477. 1 consists of a 1-D linear chain structure constructed from monocopper^II-substituted Dawson polyoxoanions, while 2 represents the first 2-D sheet-like structure with a (4,4)-connected topological net built up from plenary Dawson-type polyoxoanions and Cu^II-4,4′-bpy complex cations in polyoxometalate chemistry.     

Two new ladder-like inorganic chains constructed from Cu-containing sandwich polyoxoanions

Two heteropolyoxotungstates, K₄Na₄[Cu₂(H₂O)₈Cu₄(H₂O)₂(B-α-GeW₉O₃₄)₂]14H₂O (1) and K₈[Cu₂(H₂O)₈Cu₄(H₂O)₂(B-α-SiW₉O₃₄)₂]4H₂O (2), have been obtained in aqueous solution and characterized by IR, TG, elemental analysis, magnetism, and single-crystal X-ray analysis. The two compounds are one-dimensional (1-D) inorganic polymers composed of Cu-containing sandwich polyoxoanions, linked by additional Cu²⁺ ions to construct 1-D ladder-like chain structures. To the best of our knowledge, it is the first example of a 1-D ladder-like chain based on sandwich-type anions and Cu²⁺ linkers. Furthermore, the chains in 1 are further connected by K⁺ into an extensive three-dimensional (3-D) framework. The magnetic studies of 1 indicate that antiferromagnetic interactions exist in the central tetra-metal set of the sandwich-type polyoxoanion.     

Hybrid inorganic-organic 1-D and 2-D frameworks with {As8V14O42} clusters as building blocks

Three novel hetero-polyoxovanadates, [Cd(2,2′-bpy)₃]{[Cd(dien)]As₈V₁₄O₄₂(H₂O)} (1, 2,2′-bpy=2,2′-bipyridine, and dien=diethylenetriamine), [Zn(2,2′-bpy)₂]₂[As₈V₁₄O₄₂(H₂O)]·H₂O (2) and [Ni(en)₂]₃[As₈V₁₄O₄₂(HPO₃)]·4H₂O (3, en=ethlenediamine), were hydrothermally synthesized and characterized by single-crystal X-ray diffraction. Crystal data: 1 monoclinic, P2(1)/n, a=15.1728(5), b=19.2863(5), , β=96.005(2)°, Z=4. 2, orthorhombic, P2(1)2(1)2(1), a=12.1270(3), b=15.8678(8), , Z=4. 3, triclinic, , a=12.9340(3), b=13.4130(3), , α=87.170(3)°, β=77.517(3)°, γ=68.480(3)°, Z=2. Compounds 1-3 are all made of the {As₈V₁₄O₄₂} shells linked by corresponding transition metal complexes into extended structures. Compound 1 and 2 present 1-D wave-like and tubular structures, respectively, while compound 3 exhibits a novel 2-D structure containing interwinding puckery layers. Variable temperature susceptibility measurements demonstrate the presence of antiferromagnetic interaction between V^IV cations in 1 and 2.     

A new compound constructed from Keggin anions and Cu-5,6-diamino-1,10-phenanthroline complexes: synthesis,structure, and characterization

A new inorganic–organic hybrid based on polyoxometalate, [Cu₂(daphen)₂(H₂O)₄(PW₁₁W^VO₄₀)]?·?6H₂O (1) (daphen?=?5,6-diamino-1,10-phenanthroline), was synthesized hydrothermally and characterized by single-crystal X-ray diffraction, elemental analysis, infrared spectroscopy, and thermal analysis. Single-crystal X-ray diffraction analysis reveals that in 1 the Keggin anion [PW₁₂O₄₀]^4? is tetradentate, linking four Cu(II)-daphen fragments with its four terminal oxygen atoms in a plane; Cu²⁺ is coordinated by two terminal oxygen atoms of two [PW₁₂O₄₀]^4? anions, two water molecules, and two nitrogen atoms of the phen ring of a daphen, forming a polymeric layer. The 3-D architecture of the compound is further formed via hydrogen bonds between these layers. The daphen is bidentate chelating and does not participate in formation of hydrogen bonds. Redox of 1 was examined.     

由Keggin型簇和过渡金属配合物构筑的杂多钨酸盐锯齿链的合成和结构

采用水热法合成了一维锯齿链状的有机-无机杂化杂多钨酸盐[Cu（en）2（H2O）]{[Cu（en）2（H2O）][Cu（en）2]（α-SiW12O40）}（OH）2·H2O（记作1;en=1,2-乙二胺）;利用元素分析、红外光谱和X射线单晶衍射对其结构进行了表征.结果表明,化合物1属于三斜晶系,P-1空间群;其晶格参数为：a=1.297 6（6）nm,b=1.473 5（7）nm,c=1.909 9（9）nm,α=86.736（8）°,β=88.833（8）°,γ=74.840（8）°,V=3.519（3）nm3,Z=2.就分子结构而言,化合物1由一个常见的Keggin型多阴离子[α-SiW12O40]4-、两个不同的铜配位阳离子[Cu（en）2（H2O）]2＋和[Cu（en）2]2＋、一个游离的铜配位阳离子[Cu（en）2（H2O）]2＋、两个氢氧根离子和一个结晶水组成;相邻的[α-SiW12O40]4-多阴离子通过两个配位阳离子[Cu（en）2）]2＋相连,形成一维锯齿链状结构.     

Hydrothermal synthesis and structural characterization of three inorganic–organic composite sandwich-type phosphotungstates

Three inorganic–organic composite sandwich-type phosphotungstates [Ni(tepa)(H₂O)]₄H₂[Ni₄(H₂O)₂(α-B-PW₉O₃₄)₂]·8H₂O (1), (enH₂)₃[Ni₂(H₂O)₁₀][Ni₄(H₂O)₂(α-B-PW₉O₃₄)₂]·en·8H₂O (2) and (enH₂)₁₀[Mn₄(H₂O)₂(α-B-PW₉O₃₄)₂]₂·20H₂O (3) (tepa=tetraethylenepentamine and en=ethylenediamine) have been synthesized by the hydrothermal reaction of the trivacant Keggin polyoxoanion [α-A-PW₉O₃₄]⁹⁻ with Ni²⁺ or Mn²⁺ ions in the presence of tepa or en and structurally characterized by IR spectra, elemental analysis, thermogravimetric analysis and variable temperature magnetic susceptibility. X-ray crystallographic analyses indicate that they all contain the classical tetra-M sandwiched polyoxoanions [M₄(H₂O)₂(α-B-PW₉O₃₄)₂]¹⁰⁻ (M=Ni²⁺ or Mn²⁺) and nickel-organoamine cations or organoamine cations work as the charge balance ions. The tetra-M clusters in 1, 2 and 3 exhibit the familiar structural type of a β-junction at the sites of metal incorporation. The study of magnetic property of 1 is indicative of a typical ferromagnetic coupling between Ni²⁺ cations.     

Hydrothermal synthesis and characterization of two new bicapped Keggin heteropoly tungstovanadated derivatives

Two new heteropoly tungstovanadate derivatives, [Fe(phen)₃]₂[W_10.5V_4.5O₄₂]·3H₂O (1) and [Fe(phen)₃]₂[W₁₀V₅O₄₂].6H₂O (2) (phen=1,10′-phenanthroline), have been synthesized under hydrothermal conditions by using different starting materials, and characterized by elemental analysis, IR, ESR, XPS, TGA and single-crystal X-ray diffraction analysis. Crystal data for compound 1: C₇₂H₅₄Fe₂N₁₂O₄₅V_4.5W_10.5, monoclinic, space group C2/c, , , , β=99.882(8)°, V=10002(5) ų, Z=4; for compound 2, C₇₂H₆₀Fe₂N₁₂O₄₈V₅W₁₀, monoclinic, space group C2/c, a=30.246(6) Å, , c=25.329(5) Å, β=100.34(3)°, V=10483(4) ų, Z=4. The crystal structure analysis reveals that both polyoxoanions are decorated with the [Fe(phen)₃]²⁺ cations_, and that they have analogous structure to each other with slightly different packing modes of the polyoxoanions, [Fe(phen)₃]²⁺ cations and water molecules. They are further linked to form two-dimensional (2D) supramolecular networks through extensive hydrogen bonding.     

A 1-D ladder-like aggregate constructed from Preyssler anion and transition metal linkers

A 1-D ladder-like aggregate, K₂Na₆[Na(H₂O)Fe₂(H₂O)₈(P₅W₃₀O₁₁₀)] · 23.5H₂O (1; K₂Na₆[1a] · 23.5H₂O) has been obtained by conventional aqueous solution reaction. X-ray diffraction analysis reveals that 1 crystallizes in the monoclinic system, space group P 2 ₁ /m, a = 16.938(3) Å, b = 21.396(4) Å, c = 17.520(4) Å, β = 98.14(3)°, V = 6285(2) ų, and Z = 2. Polyoxoanion 1a shows a 1-D ladder-like chain, built up of Preyssler anion and Fe³⁺ linkers, which represents the first extended structure based on Preyssler anion and transition metal linkers. The 1-D chains in 1 are further connected into a 3-D open framework by potassium and sodium cations. Compound 1 displays electrocatalytic activity towards the reduction of nitrite.     

Synthesis and characterization of two 3-D polymeric lanthanide complexes constructed from 1,2,4,5-benzenetetracarboxylic acid

Two 3-D porous coordination polymers, [Nd(^abtec)_2/4(^bbtec)_2/4(H₂O)] _n (1) and [NdYb(^cbtec)_2/4(^dbtec)_2/4(^ebtec)_2/4(H₂O)₄] _n (2), have been prepared by the hydrothermal method at 160°C. Both complexes were characterized by elemental analyses, photoluminescence spectra, and single-crystal X-ray diffraction.     

Novel inorganic-organic hybrids constructed from multinuclear copper cluster and Keggin polyanions: from 1D wave-like chain to 2D network

Two novel inorganic-organic hybrids constructed from Keggin-type polyanions and multinuclear copper clusters based on 1-H-1,2,3-benzotriazole (HBTA), [Cu(I)(8)(BTA)(4)(HBTA)(8)(SiMo(12)O(40))]·2H(2)O (1) and [Cu(II)(6)(OH)(4)(BTA)(4)(SiW(12)O(40))(H(2)O)(6)]·6H(2)O (2), have been hydrothermally synthesized and structurally characterized by single crystal X-ray diffraction, elemental analyses, IR spectra and thermogravimetric (TG) analyses. In compound 1, eight Cu(I) ions were linked by twelve HBTA/BTA ligands to form an octanuclear Cu(I) cluster, which is connected by SiMo(12)O(40)(4-) anion with two bridging O atoms and two terminal O atoms to construct a one-dimensional (1D) wave-like chain. The octanuclear copper unit represents the maximum subunit linked just by amine ligands in the POMs system. In 2, four BTA ligands linked five Cu(II) ions constructing a pentanuclear "porphyrin-like" subunit, which is connected by another Cu(II) ion to form a 1D metal-organic band. The SiW(12)O(40)(4-) polyanions as tetradentate inorganic linkages extend the 1D band into a two-dimensional (2D) network with (8(3))(2)(8(5)·10) topology. To the best of our knowledge, compounds 1 and 2 represent the first examples of inorganic-organic hybrids based on metal-HBTA multinuclear subunits and polyoxometalates. The photocatalysis and electrochemical properties have been investigated in this paper.     

Two novel copper(II) complexes constructed from dicarboxylate ligands with different spacer lengths and 2-phenylimidazo[4,5-f]1,10-phenanthroline (PIP): Synthesis, structures and properties

Two novel metal–organic coordination polymers [Cu(PIP)(bpea)(H₂O)]·H₂O (1) and [Cu(PIP)(1,4-bdc)] (2) have been obtained from hydrothermal reaction of copper(II) with the mixed ligands [biphenylethene-4,4′-dicarboxylic acid (bpea) for 1, benzene-1,4-dicarboxylic acid (1,4-H₂bdc) for 2, and 2-phenylimidazo[4,5-f]1,10-phenanthroline (PIP)]. Both complexes have been structurally characterized by elemental analyses, IR and single-crystal X-ray diffraction analyses. Structural analyses reveal that complex 1 possesses infinite one-dimensional zigzag chain, 2 exhibits a two-dimensional (4,4) network, both of which are extended into three-dimensional supramolecular network by weak interactions. The different structures of the title complexes illustrate the influence of the flexibility (the spacer length of carboxyl groups and the structural rigidity of the spacer) of organic dicarboxylate ligands on the formation of such coordination architectures. Moreover, the thermal properties and the voltammetric behavior of complexes 1 and 2 have been reported.     

Syntheses, structures and properties of 3D inorganic-organic hybrid frameworks constructed from lanthanide polymer and Keggin-type tungstosilicate

Inorganic-organic hybrid frameworks, namely [Ce(H₂O)₃(pdc)]₄[SiW₁₂O₄₀]·6H₂O 1, [M(H₂O)₄(pdc)]₄[SiW₁₂O₄₀]·2H₂O (M=Ce for 2a, La for 2b, Nd for 2c; H₂pdc=pyridine-2,6-dicarboxylic acid) were assembled through incorporation of Keggin-type heteropolyanion [SiW₁₂O₄₀]⁴⁻ within the voids of lanthanides-pdc network as pillars or guests under hydrothermal condition. Single-crystal X-ray analyses of these crystals reveal that compound 1 presents 3D pillar-layered framework with the [SiW₁₂O₄₀]⁴⁻ anions located on the square voids of the two-dimensional Ce-pdc bilayer. Compounds 2a-c are isostructural and constructed from 3D Ln-pdc-based metal-organic framework (MOF) incorporating noncoordinating guests Keggin structure [SiW₁₂O₄₀]⁴⁻. Solid-state properties of compounds 1 and 2a-c such as thermal stability and photoluminescence have been further investigated.     

A novel 2D layer structure constructed from sandwich-type transition metal substituted tungstates and nickel coordination fragments: {[Ni(enMe)2]2[Ni(enMe)2(H2O)]2[As2W18Ni4(enMe)2O68]}·2H3O·2H2O

A novel polyoxometalate {[Ni(enMe)₂]₂[Ni(enMe)₂(H₂O)]₂[As₂W₁₈Ni₄(enMe)₂O₆₈]}·2H₃O·2H₂O (1) (enMe = 1,2-propylenediamine) has been synthesized and characterized, which is the first high-dimensional structure constructed from sandwich-type transition metal substituted tungstates and transition metal coordination groups.     

Synthesis and characterization of two 3-D polymeric lanthanide complexes constructed from 1,2,4,5-benzenetetracarboxylic acid

Two new 3-D lanthanide coordination polymers, [CeK(btec)(H₂O)₂] _n (1), [Ho(btec)_0.5(ad)_0.5(H₂O)] _n (2) (H₄btec?=?1,2,4,5-benzenetetracarboxylic acid, H₂ad?=?adipic acid), have been synthesized under hydrothermal conditions and characterized by elemental analysis, IR spectroscopy, and single-crystal X-ray diffraction. Structural analyses reveal that both complexes crystallized in monoclinic space group P2₁/c and possessed 3-D net-structures. In 1, btec adopts two types of coordination modes: µ₁₂–η²:η²:η²:η¹:η²:η²:η²:η¹ bridging mode linking six Ce(III) ions and six K⁺ ions and the other µ₈–η¹:η²:η²:η¹:η¹:η²:η²:η¹ bridging mode connecting four Ce(III) ions and four K⁺ ions. In 2, btec adopts a µ₆-bridging with each carboxylate group of btec ligand in a µ₂–η¹–η² mode, the adipate is µ₄-bridging with each carboxylate µ₂–η¹–η¹-monodentate. The topological analysis shows that 1 can be simplified to a 3-nodal net with the Schläfli symbol {3²,4⁸,5³,6²}₄{3⁴,4¹²,5¹²}{4³⁸,6²⁶,8²} and 2 can be simplified to a 3-nodal network with the Schläfli symbol {4²,8⁴}{4⁶,6⁶,8³}{4⁷,6³}₂. The thermogravimetric analyses and the X-ray powder diffraction of 1 and 2 are discussed.     

Two helical coordination polymers constructed from V-shaped and chelate ligands

The synthesis and X-ray characterization of two supramolecular isomers, [Co(oba)(2,2′-bpy)] _n (1 and 2) (oba?=?4,4′-oxybis(benzoate), 2,2′-bpy?=?2,2′-bipyridine) are reported. Crystal data for 1: a?=?12.026(2), b?=?15.120(3), c?=?11.361(2)?Å, β?=?91.46(3)°, Z?=?4, R ₁?=?0.0330, wR ₂?=?0.0949. Crystal data for 2: a?=?16.171(3), b?=?19.162(4), c?=?22.914(5)?Å, α?=?107.66(3), β?=?91.46(3), γ?=?98.99(3)°, Z?=?2, R ₁?=?0.0388, wR ₂?=?0.0456. They are conformational supramolecular isomers without solvent molecules in the structures, and exhibit different one-dimensional helical structures that are further assembled into distinct two-dimensional layers via π–π stacking interactions. The results indicate that the geometry of ligand is one of the most important factors for the construction of a helical motif.     

Three new 3-D inorganic-organic coordination polymers constructed from polyoxovanadate-based heterometallic network and flexible bis(imidazole) ligand: Syntheses, structures and properties

Three new 3-D inorganic-organic polyoxovanadate-based coordination polymers [M₂(bbi)(V₂O₆)₂(H₂O)₂] [M = Co (1), Mn (2)] and [Ni₂(bbi)₃V₄O₁₂]·4H₂O (3) (bbi = 1,1-(1,4-butanediyl)bis(imidazole)) have been synthesized under hydrothermal condition and characterized by elemental analyses, IR spectra, TG and single crystal X-ray diffraction. The 3-D networks of compounds 1 and 2 are constructed from neutral {M₂V₄O₁₂} [M = Co (1), Mn (2)] layers that are pillared via the coordination of organic ligands bbi to M sites. Compound 3 is a 3-D eight-connected network, in which each binuclear [Ni₂O₄N₆] node linked with other eight adjacent nodes through two {V₄O₁₂}⁴⁻ clusters and six bbi ligands. The electrochemical behaviors of 1-3 modified carbon paste electrodes (1-CPE, 2-CPE and 3-CPE) in 1 M H₂SO₄ aqueous solution have been reported.