A functionalized polyoxometalate by hexanuclear copper–amino acid coordination complexes

A new functionalized polyoxometalate by transition metal–amino acid coordination complexes, H₄[Na(H₂O)₂][Cu₆Na(gly)₈(H₂O)₂][BW₁₂O₄₀]₂ · 13H₂O (1) (gly = glycine) has been synthesized and characterized by elemental analysis, IR spectroscopy, TG analysis, and single crystal X-ray diffraction. Compound 1 possesses a 3D framework, which is built up of [BW₁₂O₄₀]⁵⁻ building blocks, hexanuclear [Cu₆Na(gly)₈] coordination clusters and Na⁺ ions. Furthermore, magnetic measurements show ferromagnetic interactions for compound 1.     

Two new 2D organic–inorganic hybrids assembled by lanthanide-substituted polyoxotungstate dimers and copper–complex linkers

Two new organic–inorganic hybrid copper–lanthanide heterometallic polyoxometalates (POMs), [Cu(dap)₂]_3.5[Cu(dap)₂(H₂O)]₃[La(α-SiW₁₁O₃₉)₂]·5H₂O (1) and H[Cu(dap)₂(H₂O)][Cu(dap)₂]₄[Eu(α-PW₁₁O₃₉)₂]·13H₂O (2) (dap = 1,2-diaminopropane), have been made under hydrothermal conditions and characterized by elemental analyses, IR spectra, XRD, thermogravimetric (TG) analyses and X-ray single-crystal diffraction. They both display interesting 2D organic-inorganic hybrid POMs containing 3d-4f cations and organic dap ligands. To the best of knowledge, 1 represents the first 2D Cu–Ln heterometallic silicotungstate assembled by [La(α-SiW₁₁O₃₉)₂]^13 − dimers and [Cu(dap)₂]^2 + linkers, while 2 is a new 2D Cu-Eu heterometallic Keggin-type phosphotungstate with dap ligands. Furthermore, the variable-temperature magnetic susceptibility of 2 has been investigated.     

A novel 3D POMOF based on dinuclear copper (II)-oxalate complexes and Keggin polyoxoanions with excellent photocatalytic activity

A novel coordination polymer, [Cu₂(btx)₂(C₂O₄)][H₂SiW₁₂O₄₀]·12H₂O (btx = 1,4-bis(triazol-1-ylmethyl)benzene)] (1) has been synthesized by hydrothermal reaction, and characterized by elemental analyses, IR spectroscopy, and single crystal X-ray diffraction. Compound 1 is composed of α-Keggin type [SiW₁₂O₄₀]^4 − polyoxoanions and dinuclear copper (II)-btx complexes. The dinuclear copper (II)-btx complex is a three-dimensional (3D) porous framework, in which the [SiW₁₂O₄₀]^4 − as 4-coordinating guests are encapsulated, forming a novel 3D POMOF with two kinds of open channels along both a and b axes. Additionally, compound 1 shows excellent photocatalytic properties for the degradation of methylene blue (MB) under both visible and ultraviolet (UV) light. The molecular design of 1 not only generates a new POMOF, but also opens a new avenue to produce photocatalytic materials.     

Synthesis,structural characterization and properties of a novel 1D helical chain arsenomolybdate {[Cu(en)2][Cu(en)(H2O)][(Cu(en)2(H2O)] [AsIIIAsVMo9O34)]} · 2H2O

An organic–inorganic hybrid 1D helical chain arsenomolybdate {[Cu(en)₂][Cu(en)(H₂O)][(Cu(en)₂(H₂O)] [As^IIIAs^VMo₉O₃₄)]} · 2H₂O (1) (en = ethylenediamine) has been hydrothermally synthesized and characterized by elemental analyses, IR, UV and CD spectrum, powder X-ray diffraction, TG-DTA and single-crystal X-ray diffraction. The asymmetric unit of 1 consists of a monocapped trivacant Keggin [As^IIIAs^VMo₉O₃₄]^6 − subunit, a pendant [Cu(en)₂(H₂O)]^2 + cation, a pendant [Cu(en)(H₂O)]^2 + cation, one bridging [Cu(en)₂]^2 + cation and two lattice water molecules. It should be noted that 1 illustrates a one-dimensional (1D) helical chain assembled by {[Cu(en)(H₂O)][(Cu(en)₂(H₂O)][As^IIIAs^VMo₉O₃₄)]}^2 − clusters and [Cu(en)₂]^2 + linkers.     

{[Cu(phen)]3Cl4}2[GeMo12O40]: Synthesis,crystal structure and magnetic property of a new trinuclear copper complex based on germanomolybdate

A new trinuclear copper complex based on germanomolybdate, {[Cu(phen)]₃(μ₂-Cl)₄}₂[GeMo₁₂O₄₀] (1) (phen = 1,10-phenanthroline), has been hydrothermally synthesized and structurally characterized by elemental analysis, IR spectroscopy, TG analysis, X-ray powder diffraction (XRPD) and single-crystal X-ray diffraction. Single crystal X-ray analysis reveals that the structural unit of 1 consists of two coordination cations {[Cu(phen)]₃(μ₂-Cl)₄}²⁺ (1a) and a saturated Keggin-type germanomolybdate polyoxoanion [GeMo₁₂O₄₀]^4?. In 1, the most intriguing feature is that each trinuclear copper cation {[Cu(phen)]₃(μ₂-Cl)₄}²⁺ is constructed from three [Cu(phen)]²⁺ cations bridged by four μ₂-Cl atoms. Magnetic measurements indicate 1 shows the ferromagnetic exchange interactions within Cu^II centers.     

A novel chain structure constructed from copper complexes and dimers based on bi-capped Keggin clusters

A new compound, [Cu(en)₂][Cu(en)₂(H₂O)]₂[SiMo₈V₆O₄₂][Cu(en)₂]·1.5H₂O (1) (en = ethylenediamine), has been hydrothermally synthesized and characterized by elemental analysis, IR, ESR spectrum, TG analysis and single-crystal X-ray diffraction analysis. Compound 1 represents a 1-D zigzag chain-like structure constructed from dimeric units of bi-capped polyoxoanions {[Cu(en)₂]₂[Cu(en)₂(H₂O)]₂[SiMo₈V₆O₄₂]₂[Cu(en)₂]}⁶⁻  and transition metal coordination fragment [Cu(en)₂]^2 +. The adjacent chains are further interconnected into a 3-D supramolecular structure via hydrogen bonds. The magnetic susceptibility of 1 demonstrated the presence of antiferromagnetic interactions.     

Spectroscopic studies on bis(1-amidino-O-alkylurea) copper(II) sulfate complexes where alkyl = methyl,ethyl, n-propyl or n-butyl: EPR evidence for binuclear complexes

Four new Cu(II) Complexes viz. [Cu(II)(1-amidino-O-methylurea)₂]SO₄·2H₂O (1), [Cu(II)(1-amidino-O-ethylurea)₂](SO₄)₂·2H₂O (2), [Cu(II)(1-amidino-O-n-propylurea)₂] SO₄·2H₂O (3), [Cu(II)(1-amidino-O-n-butylurea)₂]₂(SO₄)₂·2H₂O (4) have been synthesized and characterized. EPR spectrum of complex 4 at RT consisted of fine-structure transitions (ΔMs = ±1) with zero-field splitting (ZFS) of 0.0485 cm^?1 and a half-field signal (ΔMs = ±2) at ca. 1600 G, revealed formation of binuclear complex (S = 1). Whereas EPR spectrum of complex 2 in DMSO showed a mixture of mononuclear and binuclear complex in the ratio 0.75:1.0 with ZFS of 0.0385 cm^?1. From the temperature dependence of the EPR signal intensity, the isotropic exchange-interaction constant J was evaluated.     

A new polyborate anion, [B7O9(OH)6]3−: Self assembly,XRD and thermal properties of s-fac-[Co(dien)2][B7O9(OH)6]·9H2O

The title compound, s-fac-[Co(dien)₂][B₇O₉(OH)₆]·9H₂O (1) (dien = HN(CH₂CH₂NH₂)₂), has been prepared as a crystalline solid in moderate yield (35%) from the reaction of B(OH)₃ with [Co(dien)₂][OH]₃ in aqueous solution (10:1 ratio). The structure contains a novel polyborate anion [B₇O₉(OH)₆]^3 − which is structurally based on the known ‘ribbon’ isomer of [B₇O₉(OH)₅]^2 −, with an additional [OH]⁻ group coordinated to a B atom in one of the outer boroxole rings. Compound 1 is formed by a self-assembly process in which the cation and anion mutually template themselves from equilibrium mixtures under reaction conditions. The [B₇O₉(OH)₆]^3 − anions are H-bonded to each other in layers with ‘cavities’ suitable for the [Co(dien]₂]^3 + complex. Three [B₇O₉(OH)₆]^3 − anions are in the secondary coordination sphere (via H-bonds) of each cation, with each anion H-bonded to three cations.     

Syntheses,structural characterization and electrochemical properties of two rare-earth–isonicotinic-acid containing silicomolybdates

Two rare-earth–isonicotinic-acid containing silicomolybdates [NH₄]₆[RE(INA)₂(HINA)(H₂O)₃]₂[α-SiMo₁₂O₄₀]₂·6H₂O [RE = Nd^III (1), Er^III (2); HINA = isonicotinic acid] have been synthesized in the conventional aqueous solution and characterized by elemental analyses, IR spectra, UV spectra and single-crystal X-ray diffraction. Both 1 and 2 crystallize in the triclinic P–1 space group and consist of two typical Keggin [α-SiMo₁₂O₄₀]^4 − polyanions, one isolated rare-earth-isonicotinic-acid [RE(INA)₂(HINA)(H₂O)₃]₂^2 + dimeric complex cation, six NH₄⁺ ions and six lattice water molecules. Interestingly, two rare-earth ions are linked by four INA⁻ ligands in the [Ln(INA)₂(HINA)(H₂O)₃]₂^2 + complex cation, which is very rare in polyoxometalate chemistry. The UV spectral measurements of 1 indicate that 1 is stable in aqueous solution in the pH range of 4.49–9.39. Furthermore, the electrochemical and electrocatalytic properties of 1 have been measured by cyclic voltammetry in 0.5 mol·L^− 1 Na₂SO₄ + H₂SO₄ aqueous solution at the scan rate of 100 mV·s^− 1.     

An organic–inorganic hybrid nickel-substituted arsenotungstate consisting of three types of polyoxotungstate units

A new organic–inorganic hybrid nickel-substituted arsenotungstate [Na(H₂O)₃]₂[Ni(H₂O)₆]₂[Ni(H₂O)₅]{[Ni₃(dap)(H₂O)₂]₂(H₂W₄O₁₆)}{(α-H₂AsW₆O₂₆)[Ni₆(OH)₂(H₂O)(dap)₂](B-α-HAsW₉O₃₄)}₂·7H₂O (1) (dap = 1,2-diaminopropane) has been hydrothermally synthesized and structurally characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction. Crystal data for 1: C₁₈H₁₄₄As₄N₁₂Na₂Ni₂₁O₁₇₆W₃₄, Mr = 11174.92, triclinic, space group P-1, a = 15.004(4) Å, b = 16.357(5) Å, c = 22.070(6) Å, α = 80.458(5)°, β = 79.291(5)°, γ = 72.074(5)°, V = 5030(3) Å³, Z = 1, GOOF = 1.007, R₁ = 0.0703, wR₂ = 0.1670. The skeleton of 1 is a centric nanoscale cluster and is composed of two asymmetric sandwich-type clusters {(α-H₂AsW₆O₂₆)[Ni₆(OH)₂(H₂O)(dap)₂](B-α-AsW₉O₃₄)}^7? linked by a symmetric cluster {[Ni₃(dap)(H₂O)₂]₂(H₂W₄O₁₆)}⁶⁺. Notably, 1 is an interesting polyoxometalate containing the trivacant Keggin [B-α-AsW₉O₃₄]^9?, hexavacant Keggin [α-AsW₆O₂₆]^11? and tetrameric [W₄O₁₆]^8? units. Magnetic measurements indicate that 1 shows the ferromagnetic interactions within Ni^II centers.     

One-dimensional inorganic framework consisting of the sandwich-type germanomolybdate and the copper complex linker: Synthesis,crystal structure,and magnetic property

A new heteropolymolybdate, (Him)₈Na₇H₇[Cu(im)₄(CuGeMo₉O₃₃)₂][(CuGeMo₉O₃₃)₂]·41H₂O (1) (im = imidazole), was synthesized and structurally characterized by elemental analysis, IR spectra, UV electronic spectroscopy and X-ray diffraction. Compound 1 exhibits a one-dimensional chain-like framework [Cu(im)₄(CuGeMo₉O₃₃)₂]^10? with isolated [(CuGeMo₉O₃₃)₂]^12? units residing among the chains, which is first observed in sandwich-type germanomolybdate system. Electrocatalytic experiments show that compound 1 exhibits good electrocatalytic activity for nitrite reduction. The magnetic investigation indicates the existence of antiferromagnetic interactions for 1.     

Novel heterobimetallic Cu/Mn coordination polymers prepared by “direct permanganate” synthesis

Two heterometallic Cu/Mn complexes [Cu(Me₂en)₂][Mn₂(ox)₃] · 2H₂O (1) (Me₂en = N,N-dimethylethylenediamine, H₂ox – oxalic acid) and [Cu(1,3-pn)(ox)(H₂O)][Mn(ox)(H₂O)₂] · H₂O (2) (1,3-pn = 1,3-diaminopropane) are prepared by the one-pot reaction of copper powder, tetrabutylammonium permanganate, oxalic acid and N-chelating ligands. Their structures are investigated by single-crystal X-ray analysis that reveals interesting variation in bridging motives of the oxalate groups composing the Mn-polymeric fragments.     

Two octamolybdate-based hybrids functionalized by 1,3-bis[tris(hydroxymethyl)methylamino]propane ligand

Two octamolybdate-based organic–inorganic hybrids functionalized by 1,3-bis[tris(hydroxymethyl)methylamino]propane (H₆bthmap) Na₂H₄[γ-Mo₈O₂₆(H₅bthmap)₂]·2H₂O (1) and [NH₄]₆{[Cu(H₃bthmap)]₂(β-Mo₈O₂₆)} (2) have been synthesized through the aqueous synthetic method and structurally characterized by elemental analyses, IR spectra, UV spectra, thermogravimetric (TG) analysis and single-crystal X-ray diffraction. X-ray crystallography reveals that 1 consists of a classic [γ-Mo₈O₂₆]^4 − polyoxoanion decorated by two flexible [H₅bthmap]⁻ ligands through two O atoms from two [H₅bthmap]⁻ ligands and 2 contains a [β-Mo₈O₂₆]^4 − polyoxoanion with bisupporting [Cu(H₃bthmap)]⁻ anions via two terminal O atoms from the [β-Mo₈O₂₆]^4 − polyoxoanion. As far as we know, 1 and 2 represent the first octamolybdate-based hybrids with 1,3-bis[tris(hydroxymethyl)methylamino]propane ligands. The TG curves of 1 and 2 indicate two steps of weight loss and three steps of weight between 25 and 980 °C, respectively. Furthermore, the electrochemical and electrocatalytic properties of 1 and 2 have been investigated.     

pH-dependent assembly of 1D–2D structures based on both {V10O28} and [NiMo6O24H6]4 − units: Synthesis,structure and magnetic properties

Two novel complexes [H₂N(CH₂CH₂)₂O]₄[Na(H₂O)₂{O(CH₂CH₂)₂NH₂}]₂[Na(H₂O)₄]₂[V₁₀O₂₈][NiMo₆O₂₄H₆]·8H₂O (1) and [H₂N(CH₂CH₂)₂O]₆[Na(H₂O)₃]₂[V₁₀O₂₈H₂][NiMo₆O₂₄H₆]·4H₂O (2) containing both isopolyvanadate {V₁₀O₂₈} and [NiMo₆O₂₄H₆]^4 − units have been synthesized and structurally characterized for the first time, showing that the pH value of the reaction plays a key role in structure control of self-assembled processes. Compound 1 exhibits a novel one-dimensional (1-D) chain-like structure consisting of Anderson-type [NiMo₆O₂₄H₆]^4 − and isopolyvanadate [V₁₀O₂₈]^6 − anions linked by Na⁺ ions. In compound 2 with the lower pH value, [NiMo₆O₂₄H₆]^4 − and [V₁₀O₂₈H₂]^4 − anions are bridged by [Na₂O₁₀] units to form the 2D extended layer. The magnetic properties of 1 and 2 are presented.     

Synthesis and crystal structures of two new inorganic–organic hybrid polyoxomolybdate complexes: [Himi]4[{Co(imi)2(H2O)2}Mo7O24] · 4H2O and [Zn(imi)4]2[(imi)2Mo8O26] · 6H2O

The two new inorganic–organic hybrid polyoxomolybdate complexes [Himi]₄[{Co(imi)₂(H₂O)₂}Mo₇O₂₄] · 4H₂O (1) and [Zn(imi)₄]₂[(imi)₂Mo₈O₂₆] · 6H₂O (2) (imi = imidazole) have been prepared by conventional aqueous solution synthesis. Compound 1 consists of heptamolybdate anions [Mo₇O₂₄]⁶⁻ covalently linked by [CoN₂O₄]²⁺ octahedra into one-dimensional zigzag-shaped chains. The zigzag-shaped chains are further linked together via the hydrogen-bonding interactions to form a 2D supramolecular framework. Compound 2 is build up of an imidazole-coordinated octamolybdate anion, two imidazole coordinating zinc cations and lattice water molecules to form a three-dimensional framework via complex hydrogen-bonding.     

Two novel grid networks based on Keggin-type polyoxometalate clusters assembled through weak Cu⋯O interactions

Two novel grid networks based on Keggin-type polyoxoanion, formulated [Cu(2,2′-bipy)₂](HPMo₁₂O₄₀) · H₂O (1) and [Cu(2,2′-bipy)₂](HPW₁₂O₄₀) · H₂O (2) have been synthesized hydrothermally and characterized by elemental analyses, IR, EPR and X-ray single crystal diffraction. 1 is a 2D grid network built by the interconnection of bisupporting polyoxoanion clusters assembled through weak Cu⋯O interactions. The EPR spectrum of 1 indicates that its unpaired electrons are placed in d_x²−y² orbital of the ground state of Cu(II). Compound 2 is isostructural with compound 1.     

Role of spacers and substituents in the self-assembly process: Syntheses and characterization of two novel thiocyanatocuprates polymers

Two novel cation-induced complexes, {(Phen-dq) [Cu₂(SCN)₄]}_n (1) and {(Phen-dzp) [Cu₂(SCN)₄]}_n (2) [Phen-dq = (C₁₄H₁₂N₂)²⁺, 5,6-dihydropyrazino[1, 2, 3, 4-lmn]-1, 10-phenanthrolinium, Phen-dzp = (C₁₅H₁₄N₂)²⁺, 6,7-dihydro-5H-[1, 4]diazepino[1, 2, 3, 4-lmn][1,10]phenanthroline-4, 8-diium], have been synthesized via the self-assembly reaction in solution. The compound 1 possesses a two-dimensional supramolecular network linked by bridging thiocyanate groups. Complex 2 is also a two-dimensional polymeric architecture with the organic cation Phen-dzp trapped in it. Each Cu(I) atom is coordinated by two N atoms and two S atoms from four NCS groups to form a Cu₂(NCS)₂ rectangular dimer unit. In these two compounds, thanks to the difference from organic cations, the simple modification from Phen-dq to Phen-dzp leads to distinct structures between 1 and 2, and these “planar” cations are effective guests to manipulate the aggregate structure of thiocyanatocuprates.     

Ionothermal syntheses of two coordination polymers constructed from 5-sulfoisophthalic acid ligands with 1-n-butyl-3-methylimidazolium tetrafluoroborate ionic liquid as solvent

Two coordination polymers, namely, [Co(IM)₆][Co₂(SIP)₃] (1) (IM = imidazole, H₃SIP = 5-sulfoisophthalic acid) and [BMIM]₂[Cd₂(SIP)₃] (2) (BMIM = 1-n-butyl-3-methylimidazolium) were synthesized in ionothermal reactions by using ionic liquid 1-n-butyl-3-methylimidazolium tetrafluoroborate as solvent. Single-crystal X-ray analyses revealed that 1 has an anionic 1D polymeric chain charge balanced by an uncommon [Co(IM)₆]²⁺ cation. Complex 2 features an anionic 2D layer containing unique tetranuclear [Cd₄(CO₂)₆(SO₃)₂] cluster wherein the four Cd atoms are co-planar. The imidazolium cation [BMIM]⁺ of the ionic liquid acting as charge compensating agent intercalated into the [Cd₂(SIP)₂]^2n? interlayers in structure 2. The rich ionic environments of the ionic liquid may be particularly helpful in the formation of the anionic frameworks of 1 and 2.     

Binuclear rhodium(III) and iridium(III) monoselenocarboxylates: Synthesis,spectroscopy and structure of an ortho-metallated iridium complex featuring an IrCCC(μ-Se) chelate ring

Monoselenocarboxylate–bridged binuclear complexes of Rh^III and Ir^III, [(Cp1MCl)₂(μ-SeCOAr)₂] (1) (M = Rh or Ir; Cp1 = pentamethylcyclopentadienyl; Ar = Ph, C₆H₄Me–4), have been isolated either by the reaction between [Cp1₂M₂(μ-Cl)₂Cl₂] with KSeCOAr in acetonitrile or by treatment of [Cp1MCl(solvent)₂][PF₆] with KSeCOAr in acetone. The novel binuclear complexes, [Cp1IrCl(μ-SeCOAr)(κ²-SeCOC₆H₃R–)IrCp1] (2) (R = H or Me-4) with ortho-metallation at one of the iridium centres have been isolated following the use of excess AgPF₆. The single crystal structure of [Cp1IrCl(μ-SeCOC₆H₅)(κ²-SeCOC₆H₄–)IrCp1] (2a) exhibits two phenylcarboselenolate moieties situated in syn fashion with respect to the “Ir₂Se₂” plane, one of which leans towards the metal centre in order to undergo ortho-metallation after iridium–chlorine bond dissociation.     

A strategy for controlling charge and conformation in 2,2′-bipyridine complexes for use in photonic applications

The complex [ⁿBu₄N][Cu(H1)₂]·H₂O (H₂1 = 3,3′-dihydroxy-6,6′-dimethyl-2,2′-bipyridine) is readily formed from the reaction of H₂1 with [Cu(MeCN)₄][PF₆] in the presence of [ⁿBu₄N]Br; in the solid state the anion comprises a discrete dinuclear {[Cu(H1)₂](H₂O)₂[Cu(H1)₂]}^2– unit in which two oxygen atoms of each [H1]^– ligand and two water oxygens form a chair shaped hydrogen-bonded six-membered ring.