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.     

Keggin-Type Polyoxometalate Cluster Functionalized with Dinuclear M-H2biim (M = Cu, Ag) Metal–Organic Segments

Three inorganic–organic hybrid complexes, [Cu₂(H₂biim)₂(OH)₂]₂(SiW₁₂O₄₀)·2H₂O (1), [Cu₂(H₂biim)₂]₂(SiW₁₂O₄₀)·2H₂O (2) and [Ag₂(H₂biim)₂]₂(SiW₁₂O₄₀)·2H₂O (3) (H₂biim = 2, 2′-biimidazole), have been synthesized under hydrothermal conditions, and characterized by elemental analysis, IR, PXRD, TG and single-crystal X-ray diffraction. The crystallographic analysis reveals that in compounds 1–3, the Keggin polyanions [α-SiW₁₂O₄₀]^4? act as inorganic building blocks, which are linked with the dinuclear metal–organic units via Cu–O bonds in compound 1, or through supramolecular interactions in compounds 2 and 3. Compound 1 shows a 3D supramolecular structure constructed by net-like layers. Compounds 2 and 3 display 2D layer structures which were composed of wave-like chains. In addition, these compounds show electrochemical activities, and photoluminescence properties are measured in the solid state.     

Organic–inorganic hybrid complexes based on a Keggin-type polyoxoanion

Two organic?Cinorganic hybrid complexes based on a Keggin-type polyoxoanion, namely [Ni₂(H₂O)₂(bipy)₄(Hbipy)][AlW₁₂O₄₀]·7H₂O 1 and [Ni₂Cl₂(bipy)₃(Hbipy)₂][SiW₁₂O₄₀]·2.5H₂O 2 (bipy?=?4,4??-bipy), have been synthesized and characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis, and single-crystal X-ray diffraction. Complexes 1 and 2 possess similar 2D layer structures, constructed from 1D zigzag chains {Ni(bipy)} _n ²ⁿ⁺ and alternatively arranged Keggin anion and bipy linkers. Photocatalytic investigations indicate that both 1 and 2 exhibit photocatalytic activity for the degradation of Rhodamine B.     

Supramolecular compounds constructed from Keggin anions and metal–organic complex cations of 3-aminopyrazine-2-carboxylic acid

Three new supramolecular compounds based on Keggin-type polyoxometalate (POM) and transition metal complexes, [M(Hapca)₂(H₂O)₂]₂[SiW₁₂O₄₀]·nH₂O, (M = Ni^II(1), Zn^II(2), n = 12; Co^II (3), n = 15; Hapca = 3-aminopyrazine-2-carboxylic acid), have been synthesized in aqueous solution and characterized by single-crystal X-ray diffraction, elemental analysis, TG analyses, IR and fluorescence spectroscopy. The X-ray structrual analysis reveals that three compounds are isostructural with a P21/c space group. [M(Hapca)₂(H₂O)₂] ₂ ⁴⁺ are linked together via O···N hydrogen-bonding interaction to give birth to 2D layer with rectangle grids. Anions [SiW₁₂O₄₀]^4? are located in the cavities and link the 2D layers into 3D supramolecular architecture via hydrogen bonds. The compounds represent the first examples of self-assembly of 2D metal–Hapca complex supramolecular “host” networks formed by hydrogen bonding interactions and “guest” polyoxoanion species. In addition, solid-state luminescence properties of compounds 2 and 3 have been studied at room temperature.     

Influence of metal ions on the structures of Keggin polyoxometalate-based solids: Hydrothermal syntheses, crystal structures and magnetic properties

Three new Keggin polyoxometalate (POM)-based compounds linked to 3d metal complexes have been synthesized under hydrothermal conditions: [Cu(phen)₂]₂{[Cu(phen)]₂ [SiMo₁₂O₄₀(VO)₂]} (1), {[Zn(phen)₂]₂[GeMo₁₂O₄₀(VO)₂]}{[Zn(phen)₂(H₂O)]₂ [GeMo₁₂O₄₀(VO)₂]}·3H₂O (2) and {[Co(phen)₂]₂[PMo₁₂O₄₀(VO)₂]}{[Co(phen)₂(OH)]₂ [PMo₁₂O₄₀(VO)₂]}·2.5H₂O (3) (phen=1,10-phenanthroline). These three compounds present, as building blocks, the bicapped Keggin anions [XMo₁₂O₄₀(VO)₂] (X=Si, Ge and P). Compound 1 consists of a bicapped Keggin anion [SiMo₁₂O₄₀(VO)₂]²⁻ linked to two [Cu(phen)]⁺ complexes with two [Cu(phen)₂]⁺ countercations. Compound 2 contains two bicapped Keggin anions [GeMo₁₂O₄₀(VO)₂]⁴⁻, one linked to two [Zn(phen)₂(H₂O)]²⁺ cations and the other one linked to two [Zn(phen)₂]²⁺ cations. Compound 3 is a two-dimensional POM-based square network formed by bicapped Keggin anions [PMo₁₂O₄₀(VO)₂]⁴⁻ connected by [Co(phen)₂]²⁺ cations. Discrete bicapped Keggin anions [PMo₁₂O₄₀(VO)₂] linked to two [Co(phen)₂(OH)]⁺ cations are located between the layers. The magnetic properties show the presence of antiferromagnetic interactions among the reduced Mo(V) atoms (in the three compounds) plus a paramagnetic contribution from the V(IV) atoms (in 1 and 2). Compound 3 shows, in addition, an antiferromagnetic interaction between the Co(II) and the V(IV) ions directly linked through an oxygen bridge. The low-temperature ESR spectra of compound 3 confirm the presence of the reduced Mo(V) ions and the antiferromagnetic coupling between the Co(II) and the V(IV) ions.     

A new Keggin-type heteropolyanion decorated with dinuclear copper-organic coordination ions: {[Cu(Phen)(μ-Cl)Cu(Phen)<Subscript>2</Subscript>]<Subscript>2</Subscript>[SiW<Subscript>12</Subscript>O<Subscript>40</Subscript>]} · H<Subscript>2</Subscript>O

A new Keggin-type heteropolyanion decorated with dinuclear copper-organic coordination ions, {[Cu(Phen)(μ-Cl)Cu(Phen)₂]₂[SiW₁₂O₄₀]}· H₂O (I), has been hydrothermally synthesized and structurally characterized by IR spectroscopy and single-crystal X-ray diffraction. X-ray crystallography analysis showed that two dinuclear copper-organic [Cu(Phen)(μ-Cl)Cu(Phen)₂]³⁺ units are supported on the reduced α-Keggin polyoxoanion [SiW₁₂O₄₀]^6? via two terminal oxygen atoms from opposite sides of the Keggin polyoxoanion, and I further acts as a neutral molecular unit for the construction of a one-dimensional chain-like framework by \(C - H \cdots Cl\) hydrogen bonds and π-π-stacking interactions.     

Synthesis, crystal structure and electrochemical behavior of tetranuclear transition metal clusters based on lacunary silicotungstates: [M4(H2O)2(SiW9O34)2]10− (M = Ni2+, Co2 +) and [Fe4(μ-O)2(μ-OH)2(SiW10O37)2]14−

Three tetranuclear transition metal clusters based on lacunary silicotungstates [M₄(H₂O)₂(SiW₉O₃₄)₂]^12? (M = Ni²⁺ (1), Co²⁺ (2)), and [Fe₄(μ-O)₂(μ-OH)₂(SiW₁₀O₃₇)₂]^14? (3) have been synthesized under ambient conditions and characterized by elemental analyses, IR, TG, cyclic voltammetry, and single-crystal X-ray diffraction. The polyoxoanions of 1 and 2 are isostructural, including a central rhomb-like {M₄O₁₆} (M = Ni, Co) cluster sandwiched by two trivacant {B-α-SiW₉} Keggin moieties. In the polyoxoanion of 3, two μ-OH and two μ-O bridges link with four Fe^III ions, forming an eight-membered ring. This [Fe₄(μ-OH)₂(μ-O)₂] aggregation is sandwiched by two bi-vacant {α-SiW₁₀} Keggin fragments. The electrochemical properties of the three compounds were investigated.     

Zn-containing double complex salts formed by Keggin type polyoxotungstates: Synthesis and crystal structure

Novel double complex salts, [Zn(DMF)₆]₂[SiW₁₂O₄₀] · 2H₂O (I) and [Zn(H₂O)₂(DMF)₄][Zn(DMF)₆]₂[PW₁₂O₄₀]₂ · 6DMF (II) (DMF = N,N-dimethylformamide), were prepared by the reaction of Zn²⁺ and heteropoly acids H_x[EW₁₂O₄₀] · xH₂O (E = P, X = 3, E = Si, X = 4) in DMF. Compounds I and II were studied by X-ray diffraction (СIF files CCDC nos. 1497570 (I) and 1497571 (II)) and IR spectroscopy.     

Hydrothermal syntheses, crystal structures and properties of 0-D, 1-D and 2-D organic-inorganic hybrid borotungstates constructed from Keggin-type heteropolyanion [α-BW12O40] and transition-metal complexes

Three novel organic-inorganic hybrid borotungstates {[Ni(phen)₂(H₂O)]₂H(α-BW₁₂O₄₀)}·4H₂O (1), [Cu^I(2,2'-bipy)(4,4′-bipy)_0.5]₂{[Cu^I(2,2′-bipy)]₂Cu^I(4,4′-bipy)₂(α-BW₁₂O₄₀)} (2) and {[Cu^I(4,4′-bipy)]₃H₂(α-BW₁₂O₄₀)}·3.5H₂O (3) (phen=1,10-phenanthroline, 2,2′-bipy=2,2′-bipyridine, 4,4′-bipy=4,4′-bipyridine) have been hydrothermally synthesized and structurally characterized by elemental analyses, IR, UV spectra, powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), single-crystal X-ray diffraction, X-ray photoelectron spectroscopy (XPS) and photoluminescence. The structural analysis reveals that 1 consists of a 0-D bisupporting polyoxometalate cluster where two [Ni(phen)₂(H₂O)]²⁺ cations are grafted on the polyoxoanion [α-BW₁₂O₄₀]^5- through two terminal oxygen atoms, 2 shows a 1-D infinite chain constructed from [α-BW₁₂O₄₀]^5- polyoxoanions and {[Cu^I(2,2′-bipy)]₂Cu^I(4,4′-bipy)₂}³⁺ cations by means of alternating fashion, and 3 displays an unprecedented 2D extended structure built by [α-BW₁₂O₄₀]^5- polyoxoanions and -Cu^I-4,4′-bipy- linear chains, in which each [α-BW₁₂O₄₀]^5- polyoxoanion acts as a tetradentate inorganic ligand and provides three terminal oxygen atom and one two-bridging oxygen atom. The presence of Ni^II and W^VI in 1, Cu^I ions and W^VI in 2 and 3 are identified by XPS spectra. The photoluminescence of 2 and 3 are also investigated.     

Honeycomb-like layers constructed by hydrogen bonds. Synthesis, structure, and property of two new supramolecular compounds based on polyoxotungstate

Two new compounds based on polyoxotungstate [Co₂(PCA)₄(H₂O)₆][SiW₁₂O₄₀]·8H₂O (1), [Cd₂(PCA)₄(H₂O)₆][SiW₁₂O₄₀]·8H₂O (2) (PCA = pyridine-4-carboxylic acid) are prepared and characterized by single crystal X-ray diffraction, elemental analysis, IR spectroscopy, and thermal analysis. The results of the single crystal X-ray diffraction analysis reveal that 1 and 2 are isomorphic and two water molecules in the compounds act as the bridging groups of two cobalt or cadmium atoms, forming dinuclear coordination cations. The ligand PCA adopts a monodentate coordination mode and its uncoordinated carboxyl oxygen atom and the protonized nitrogen atom form hydrogen bonds with other ligands, by which the cations are linked into a supramolecular 2D network with hexagonal grids. The polyoxotungstate anions are arranged above and below the cationic grids. A strong emission peak at 420 nm of 2 is attributed to a ligand-metal transition.     

Hydrothermal syntheses, crystal structures of three new organic–inorganic hybrids constructed from Keggin-type [BW12O40] clusters and transition metal complexes

Three new organic–inorganic hybrid compounds constructed from Keggin-type polyanions and transition metal complexes, [Mn(2,2′-bipy)₃]_1.5[BW₁₂O₄₀Mn(2,2′-bipy)₂(H₂O)]·0.25H₂O (1), [Fe(2,2′-bipy)₃]_1.5[BW₁₂O₄₀Fe(2,2′-bipy)₂(H₂O)]·0.5H₂O (2) and [Cu₂(phen)₂(OH)₂]₂H[Cu(H₂O)₂{BW₁₂O₄₀Cu_0.75(phen)(H₂O)}₂]·1.5H₂O (3), have been hydrothermally synthesized and characterized by elemental analyses, IR, TGA and single-crystal X-ray diffraction. Compounds 1 and 2 are isostructural and both exhibit monosupporting polyoxometalate cluster structure, each of which contains a [BW₁₂O₄₀]⁵⁻ cluster decorated by one transition metal complex. Compound 3 contains a bisupporting polyoxometalate cluster anion where two {Cu_0.75(phen)(H₂O)}^0.75+ fragments are supported on the polyoxometalate dimer {Cu(H₂O)₂(BW₁₂O₄₀)₂}⁸⁻, this represents the first bisupporting polyoxometalate cluster based on a Keggin-type polyoxometalate dimer, which are further packed together via π–π stacking contacts into an extended 1-D chain.     

Channel Structure Formed by Hydrogen Bonds and Filled by Water Molecules and Dodecatungstosilicate Anions

A new compound consisting of Keggin-type polyoxometalate and transition metal complex, [Cr(apca)₂(H₂O)₂]₄[SiW₁₂O₄₀]·12H₂O(1), (apca^??=?3-aminopyrazine-2-carboxylate anion), was synthesized with conventional method and characterized by single crystal X-ray diffraction, elemental analysis, IR spectroscopy, TG analyses, PXRD. Fluorescent property was explored. The [SiW₁₂O₄₀]^4? anions and complex cations [Cr(apca)₂(H₂O)₂]⁺ in compound 1 are connected by hydrogen bonds and π–π interaction, forming the 3D structure. Especially, [Cr(apca)₂(H₂O)₂]⁺ cations are linked into left-hand helical chain extending along c-axis through hydrogen bonds, forming a channel A. The chains connect other four chains from four directions also through hydrogen bonds, then the four chains enclose a channel B whose inside dimension is a little bigger than that of A, polyoxoanions fill in the channel B, and free waters in the channel A. Compound 1 shows an asymmetric wide emission band at λ_max?=?435 nm, which may belongs to the intraligand π*?→?π transition.     

Supramolecularly assembled water layers stabilized by sebacic anions in complexes of Zn(II) and Co(II)

Two three-dimensional supramolecular water architectures, [Zn(phen)₃]₂·[Zn(C₁₀H₁₆O₄)·(H₂O)₃]·(C₁₀H₁₆O₄)₂·20H₂O (1) and [Co(phen)₃]₂·[Co(H₂O)₆]·(C₁₀H₁₆O₄)₃·30H₂O (2) [phen = 1,10-Phenanthroline, C₁₀H₁₆O₄ = sebacic dianion], have been synthesized and characterized by IR, elemental analysis, thermogravimetric analysis, and single-crystal X-ray diffractions. The two structures both contain extensive hydrogen bonding between water molecules as well as between water molecules and sebacic anions. The water molecules and sebacic acid O atoms assembled 2D supramolecular corrugated sheets with different morphology in the two complexes.     

Syntheses and electrochemical properties of three supramolecular architectures based on Keggin silicontungstates and different metal-organic units

Three new compounds [Mn(H₂O)₂(bimb)₂(H₃SiW₁₂O₄₀)₂](bimb)₄ (1), [Zn₂(bimb)₄(H₂O)₄][SiW₁₂O₄₀] (2), and [Ni₂(bimb)₄(H₂O)₄][SiW₁₂O₄₀] (3) (bimb = 1,3-bis(1-imidazoly)benzene) have been synthesized under the same hydrothermal reaction except for tuning the metal cations (Mn²⁺, Zn²⁺, and Ni²⁺). Structural characterizations show that the three compounds possess distinct structural motives. Compound 1 displays a supramolecular one-dimensional (1 D) chain formed by π···π interactions that occur among the almost parallel bimb ligands from adjacent [Mn(H₂O)₂(bimb)₂(SiW₁₂O₄₀)₂] dimers. Compound 2 shows a supramolecular two-dimensional (2D) layer achieved by intermolecular (C–H···O) hydrogen bondings between the Zn₂(bimb)₄ molecular loops and the SiW₁₂ anions. Compound 3 also exhibits a supramolecular 2D layer, but it is different from 2, which is generated by the π···π interactions among adjacent 1D polymeric chains. The distinct structural features of the three compounds suggest that the metal cations should play a significant role in the process of assembly. Additionally, the electrochemical properties of compounds 1–3 have been investigated, and the results indicate that compounds 1–3 possess excellent electrocatalytic activity toward reduction of both iodated and nitrite molecules.     

The Oxalato-Titanium-Containing Tungstophosphate(V) Dimers, [Ti8(C2O4)8P2W18O76(H2O)4]18− and [Ti6(C2O4)4P4W32O124]20−

The oxalato-titanium(IV)-containing, dimeric 18-tungsto-2-phosphate [Ti₈(C₂O₄)₈P₂W₁₈O₇₆(H₂O)₄]^18? (1) and the 32-tungsto-4-phosphate [Ti₆(C₂O₄)₄P₄W₃₂O₁₂₄]^20? (2) are formed upon reaction of the oxalato-titanium complex [TiO(C₂O₄)₂]^2? with the trilacunary Keggin precursor [A-α-PW₉O₃₄]^9? and the hexalacunary Wells–Dawson precursor [H₂P₂W₁₂O₄₈]^12?, respectively. Polyanion 1 consists of two {PW₉} units encapsulating eight titanium centers and connected to each other via two Ti–O–Ti bridges, and crystallizes as a mixed potassium-sodium-lithium salt in the triclinic space group $P{\bar{1}}$ . Polyanion 2 comprises two {P₂W₁₆} units containing each two titanium atoms, and the two half-units are connected via two titanium atoms decorated by two oxalate groups each, and crystallizes as a mixed potassium-lithium salt in the rhombohedral space group $R{\bar{3}}c$ . Polyanions 1 and 2 were characterized in the solid state by single-crystal XRD, FT-IR, and TGA, whereas polyanion 2 was also investigated by ³¹P and ¹⁸³W NMR.     

Solvent-dependent formation of two different Cd(II) complexes with p-BrC6H4C(S)NHP(O)(OiPr)2 (HL). Crystallographic modification of Cd(HL)2L2

Reaction of the potassium salt of N-(diisopropoxyphosphoryl)-p-bromothiobenzamide p-BrC₆H₄C(S)NHP(O)(OiPr)₂ (HL) with Cd(II) cations in freshly dried and distilled EtOH leads exclusively to the complex [Cd(p-BrC₆H₄C(S)NH₂-S)(L-O,S)₂] ([Cd(L^I)L₂]), while the same reaction in H₂O leads to the complex [Cd(HL-O)₂(L-O,S)₂] ([Cd(HL)₂L₂]). The corresponding reactions with Zn(II) always lead to the complex [Zn(L-O,S)₂] ([ZnL₂]) regardless of the solvent. The crystal structure of [Cd(HL)₂L₂]^.2/3H₂O reveals to be a polymorph to the previously reported anhydrous [Cd(HL)₂L₂].     

A Novel 12-Tungstovanadate Doubly-Grafted by Zn-Complexes: Synthesis, Crystal Structure and Properties

A novel vanadium-centered tungstovanadate, {[Zn(phen)₂(H₂O)]₂[VW₁₂O₄₀]}·3H₂O (1) (phen = 1,10-phenanthroline), has been hydrothermally synthesized and characterized by elemental analysis, single-crystal X-ray diffraction, IR spectroscopy and thermogravimetric analysis. Single-crystal X-ray diffraction at 293 K reveals that 1 consists of a [VW₁₂O₄₀]^4? Keggin unit doubly-grafted by a [Zn(phen)₂(H₂O)]²⁺ complex. The modified carbon-paste electrode of this tungstovanadate displays good electrocatalytic activity not only towards normal inorganic molecules NO₂ ^?, BrO₃ ^? and H₂O₂, but also biological molecule vitamin C. To some extent, this work shows that vanadium can be introduced into a polyoxometalate-modified electrode to facilitate catalytic oxidation or reduction of some chemical materials. Furthermore, this tungstovanadate shows high photoactivity with respect to degradation of methylene blue.     

Polyoxometalate-based supramolecular hybrids composed of Cu/2, 2′-dimethyl-4, 4′-bithiazole fragments extended via non-bonding S···O interactions

Four polyoxometalate-based complexes, namely [Cu^I(dm4bt)₂]₃[PMo₁₂O₄₀] (1), H₂[Cu^I(dm4bt)₂]₂{[Cu ₂ ^I (dm4bt)₃]₂[SiW₁₂O₄₀]}[SiW₁₂O₄₀] (2), [Cu^I(dm4bt)₂]₅ {[Cu^I(dm4bt)][P₂W₁₈O₆₂]} (3) and {Cu ₂ ^II (dm4bt)₂[Mo₆O₂₀]} (4) (dm4bt = 2,2′-dimethyl-4,4′-bithiazole), were synthesized hydrothermally from copper nitrate and various polyoxoanions. X-ray crystal structural analysis reveals that all four complexes have supramolecular structures, in which the dm4bt ligands coordinate with the Cu atoms to give different Cu/dm4bt fragments, which are further connected into supramolecular structures via non-bonding S···O interactions between Cu/dm4bt fragments and polyoxoanions. The crystal structures also reveal the crucial role of S···O interactions in the packing structures of complexes 1–4. The electrochemical and electrocatalytic properties of 1–3 with respect to bromate reduction were investigated.     

Synthesis and spectroscopy studies of new neodymium(III) complexes with cyanamide derivatives as N-Donor ligand

Four new complexes [Nd(phen)₂(pcyd)₃] (1), [Nd(phen)₂(2-Clpcyd)₃] (2), [Nd(phen)₂(2,3,5-Cl₃pcyd)₃] (3) and [Nd(phen)₂(2,3,4,5-Cl₄pcyd)₃] (4) where pcyd = phenylcyanamide anion, 2-Clpcyd = (2-chlorophenyl)cyanamide anion, 2,3,5- Cl₃pcyd = (2,3,5-threechlorophenyl)cyanamide anion and 2,3,4,5-Cl₄pcyd = (2,3,4,5-tetrachlorophenyl)cyanamide anion, were prepared and characterized by IR, UV-Vis and ¹H NMR spectroscopy as well as elemental analysis. The ¹H NMR spectra of these complexes show broadening of ligand protons attributed to coordination of paramagnetic center.     

An unprecedented extended architecture constructed from a 2-D interpenetrating cationic coordination framework templated by SiW12O40 anion

A novel inorganic-organic hybrid compound based on polyoxometalates (POMs) and organic ligand formulated as [Cu₂(bpp)₄(H₂O)₂](SiW₁₂O₄₀)∼6H₂O (1) [bpp=1,3-bis(4-pyridyl)propane], was hydrothermally synthesized and structurally characterized by elemental analysis, single-crystal X-ray diffraction analysis, IR, TG, and cyclic voltammetry. Crystal data for 1: Orthorhombic, Pbcn, a=23.0085(19) Å, b=14.6379(12) Å, c=23.6226(19) Å, V=7956.0(11) Å³, Z=4, Dc=3.315 g cm^-3, and R(final)=0.0826. X-ray diffraction study reveals that compound 1 was the first interpenetrating network of 2-D metal-organic cationic coordination framework [Cu₂(bpp)₄(H₂O)₂]_n⁴ⁿ⁺, in which Keggin-type anions SiW₁₂O₄₀^4- has been used as a non-coordinating anionic template. The electrochemical property of 1-bulk modified carbon paste electrode (1-CPE) has been studied, and the results indicate that 1-CPE has good electrocatalytic activities toward the reduction of nitrite in 1 M H₂SO₄ aqueous solution.