2D materials have strong intermolecular van der Waals forces, and 2D superlattice heterostructures have exhibited many dramatic photo-electrochemical properties for energy conversion and storage. Herein, based on the excellent properties of reduced graphene and superlattice structures, we constructed a 2D flexible superlattice polyoxometalate/rGO heterojunction with enhanced electron-hole separation via interfacial self-assembly engineering to further fabricate DSSCs based on the heterojunction-modified photoanode, which exhibited good electron transport properties. Selecting two kinds of Dawson POMs (P2W15V3, P2W18 and the corresponding heteropoly blue) as the research object, the polyoxometalate superlattice structure was obtained by the self-assembly strategy, and characterized by IR, UV-Vis, XRD, EDX and XPS. The TEM and AFM results indicated that the monolayer POM superlattice structure and superlattice polyoxometalate/rGO heterojunction were successfully obtained. The superlattice P2W18(HPB)/rGO heterojunction was introduced into the DSSCs photoanode, and electrochemical tests indicated that the superlattice polyoxometalate/rGO heterojunction improved the electron-hole separation rate, inhibited the electron recombination, and improved the photoelectric conversion efficiency to 8.09%. The 2D superlattice heterojunction remarkably improved the electrochemical performances of the energy storage and conversion systems.

Using moderate hot water to compound a novel Zn3(PO4) 2(H2O)4 salt with three-dimensional open cage construction,against which infrared spectrum,elemental analysis,thermogravimetric analysis and single crystal X-ray diffraction analysis were made.It is turned out that title compound crystal belongs to orthorhombic system;Pnma space groups,cell parameters a=1.0602(2)nm,b=1.8218(4)nm,c=5.0434(10)nm,α=β=γ= 90.00°,V=0.97410nm3,Z=4,R 1=0.0278,wR 2=0.0841,M=458.142.Firstly,four-membered ring and octatomic ring formed a two-dimensional layer structure in parallel to 0,1,1 direction,then the layer structure formed a three-dimensional open cage construction along 1,0,0 direction.

Two classic polyozornetalate-based compounds, (H2BBI)(3) center dot [P2W18O62] center dot H2O (1), H-2(H2BBI)(2) center dot [P2W18O62] center dot 2H(2)O(2) [BBI = 1, 1-(1,4-butanediyl)-bis(imidazole)], were synthesized under different solvents. The structures of the two compounds were characterized by elemental analysis, single crystal X-ray diffraction and FTIR spectra. Compound 1 was constructed into a novel 3D supermolecule through bridge and terminal oxygen atoms of Dawson type anions, and free water molecules. Compound 2 crystallized in chiral space group P1 through changing the spatial arrangement of the organic ligand BBI molecules with changing the solvent. The photocatalysis properties of the two compounds were also studied.

One new polyoxometalate compound H-3(Tea)(Bmim)(3)[P2W18O62]center dot 3H(2)O (Tea = triethylamine, Bmim = 1-methyl-3-ethylimidazole) (1) and three new polyoxometalate-based metal organic frameworks (PMOFs) Cu-II(Bbi)(1,5)(H(2)Bbi)(2)[P2W18O62] (Bbi = 1,1-(1,4-butanediyl)-bis(imidazole)) (2), Cu-2.5(II)(Mimin)(HMimin)(Bbi)(3)[P2W18O62]center dot 3H(2)O (Mimin = methylimidazol) (3), and Cu-II(Bbtz)(H(2)Bbi)(H(2)Btp)[P2W18O62] (Bbtz = 1,4-bis(triazol-1-ylmethyl)benzene, Btp = 1,3-Bis(1,2,4-triazol-1-yl)propane) (4) have been synthesized under ionothermal conditions using an ionic liquid (IL) [Bmim]Br (Bmim = 1-ethyl-3-methylimidazole) as solvent. Their structures were determined by single crystal X-ray diffraction. Compound 1 possesses a one-dimensional (ID) supramolecular chain-like structure constructed from [P2W18O62](6-) anions, Bmim, Tea, and water molecules. Compound 2 has a two-dimensional (2D) (6,3)-layer structure built by [P2W18O62](6-) anions, copper ions, and Bbi ligands. Compounds 3 and 4 are three-dimensional (3D) PMOFs with novel (6.8.10)(4.6.8(3).10)(4.6.8(3).12) and classic (6(5).8)(6(5).8)-cds topologies, respectively. Compounds 2-4 represent the first examples of PMOFs synthesized by the ionothermal method. The successful synthesis of compounds 2-4 suggests that ionothermal synthesis will be a very promising synthetic technique for assembling new PMOFs. Additionally, the properties of the four compounds have been studied in detail.

A new inorganic–organic hybrid complex, Na2[{Ag10(NC5H4COO)8(H2O)6}(SiW12O40)] (1), has been successfully synthesized from [SiW12O40]4− anions, Ag+ ions and 1,3-bis(4-pyridyl)propane under hydrothermal conditions and characterized by elemental analyses, IR spectroscopy, TG analyses, and single-crystal X-ray diffraction. In complex 1, each [SiW12O40]4− anion connects with six Ag atoms and in turn each Ag atom links to three [SiW12O40]4− anions, leading to a (6,3) layer. Such (6,3) layers are arranged in parallel and further linked by [Ag(H2O)(NC5H4COOH)2]− fragments to generate a 3D framework. The most striking feature in this work is that 1,3-bis(4-pyridyl)propane converses to isonicotinic acid in the synthetic reaction of 1, which may be induced by the combined function of Ag+ ion and polyoxometalate.

Three new organic–inorganic hybrid complexes based on the Wells–Dawson polyoxoanion, namely (H2bpp)[Ni2(bpp)2(H2O)4(P2W18O62)]·H2O 1, [Cu6(Hbpy)6(bpy)3(P2W18O62)2]·2H2O 2 and (Him)5[Cu(im)2(P2W18O62)]·4H2O 3 [bpp = 1,3-bis (4-pyridyl) propane, bpy = 4,4′-bipyridine, im = imidazole] have been synthesized and characterized. Complex 1 exhibits a three-dimensional (6, 3)-connected framework with anatase topology constructed from [α-P2W18O62]6− clusters and [Ni(bpp)]2+ fragments. Each [α-P2W18O62]6− anion links to six nickel atoms through six terminal oxygen atoms from four polar and two equatorial WO6 octahedra, which shows a novel coordination mode of a Wells–Dawson cluster with a transition-metal atom. Complex 2 displays an interesting one-dimensional double-chain structure built from [α-P2W18O62]6− clusters and [Cu2(bpy)(Hbpy)2]2+ fragments. To our knowledge, complex 2 represents the first double-chain organic–inorganic hybrid complex based on a Wells–Dawson-type cluster. Complex 3 possesses a one-dimensional zigzag chain structure constructed from [α-P2W18O62]6− anions and [Cu(im)2]+ units through weak Cu···O interactions.

Cd(OAc)(2)center dot 2H(2)O and MnCl2 center dot 4H(2)O were separately introduced to the mixture of MoO3, H3PO4 and bpy. Two new reduced molybdenum phosphate [P4Mo6O28(OH)(3)](9-) ({P4Mo6}) extended inorganic-organic hybrid supramolecular networks (H(2)bpy)(2)[Cd(H2O)](3)[Cd(HPO4)(6)(PO4)(2)(OH)(6)(MoO2)(12)]center dot 5H(2)O (1) and (H(2)bpy)(3)[Mn(H2O)(2)](2)[Mn (HPO4)(6)(PO4)(2)(OH)(6)(MoO2)(12)]center dot 10H(2)O (2) have been synthesized under hydrothermal techniques. Here, compounds 1 and 2 have been characterized by elementary analyses, IR, TG, and single crystal X-ray diffraction. Compound 1 crystallized in the triclinic, space group P (1) over bar, a=1.1877(2) nm, b=1.348 5(3) nm, c=1.410 8(3) nm, alpha=106.87(3)degrees, beta =108.09(3)degrees, gamma = 107.92(3)degrees, V = 1.848 3(6) nm(3), Z = 1; Compound 2 crystallized in the triclinic, space group P (1) over bar, a = 1.196 8(2) nm, b = 1.335 4(3) nm, c = 1.462 0(3) nm, alpha = 77.58(3)degrees, beta = 67.97(3)degrees, gamma = 76.12(3)degrees, V = 2.082 2(7) nm(3), Z = 1. The polyanion of compound 1 [Cd(H2O)](3)[Cd(HPO4)(6)(PO4)(2)(OH)(6)(MoO2)(12)](2-) is composed of Cd[P4Mo6](2) dimer and tri-nuclear {Cd-3} linkers, which are connected together to form inorganic chains. The polyanion [Mn(H2O)(2)](2)[Mn(HPO4)(6)(PO4)(2)(OH)(6)(MoO2)(12)](3-) of compound 2 exhibits a 2D inorganic layer, consisting of Mn[P4Mo6](2) units linked by the Mn2+ ions. These two kinds of inorganic extended structures are further linked with Hydrogen bonds of protonated bpy to construct different 3D supramolecular networks. Simultaneously, the electrochemical property of compound 2 has been explored. CCDC: 661669, 1; 661670, 2.

With the use of a flexible N-donor ligand 1,3-bis(4-pyridyl)propane (bpp), a new porous framework with Wells-Dawson clusters as nodes and Ni2+ ions as linkers, [Ni(bpp)(H2O)2]3[P2W18O62]·∼24H2O (1), has been successfully obtained. Topological analysis indicates that 1 possesses a perovskite structure. As a porous framework, 1 displays adsorption behavior toward H2O and CH3OH.

向MoO_3,H_3PO_4和bpy(4,4'-bipyridine)组成的反应体系中分别引入Cd(OAc)_2·2H_2O和MnCl_2·4H_2O,在水热条件下合成了两种基于还原型钼磷酸盐[P_4Mo_6O_(28)(OH)_3]~(9-)(简称{P_4Mo_6})为建筑单元构筑的新型多维延展型无机-有机杂化材料(H_2bpy)_2[Cd(H_2O)]_3[Cd(HPO_4)_6(PO_4)_2(OH)_6(MoO_2)_(12)]·5H_2O(1)和(H_2bpy)_3[Mn(H_2O)_2]_2[Mn(HPO_4)_6(PO_4)_2(OH)_6(MoO_2)_(12)]·10H_2O(2),并通过元素分析、红外光谱、热重分析和X射线单晶衍射对其进行了表征.结果表明.化合物1和2均属于三斜晶系,P(1)空间群.化合物1的阴离子[Cd(H_2O)]3[Cd(HPO_4)_6(PO_4)_2(OH)_6(MoO_2)_(12)]~(2-)是由二聚体Cd[P_4Mo_6]_2通过{Cd_3}簇依次连接形成的一维无机链状结构;化合物2的阴离子[Mn(H_2O)_2]_2[Mn(HPO_4)_6(PO_4)_2(OH)_6(MoO_2)_(12)]3-则是由二聚体Mn[P_4Mo_6]_2通过Mn~(2+)离子连接形成的二维无机层状结构.这2种无机延展结构均同质子化的bpy通过氢键作用形成不同的三维超分子网络.同时还探讨了化合物2的电化学性质.

Cd(OAc)2·2H2O and MnC12 ·4H20 were separately introduced to the mixture of MOO3, H3PO4 and bpy. Two new reduced molybdenum phosphate [P4o6O28COH)3}]9- ({P4MO6}) extended inorganic-organic hybrid supramolecular networks (H2bpy)2[Cd(H20)] 3[Cd(HPO4)6(PO4)2(OH) 6(MoO2)12]-5H2O (1) and (H 2bpy)3[Mn(H2O)2]2[Mn (HPO4)6 (PO4)2(OH) 5(MoO2)12] · 10H2O (2) have been synthesized under hydrothcrmal techniques. Here, compounds 1 and 2 have been characterized by elementary analyses, IR, TG, and single crystal X-ray diffraction. Compound 1 crystallized in the triclinic, space group P1̄, a= 1.187 7(2) nm, b = 1.348 5(3) nm, c= 1.410 8(3) nm, α=106.87(3)°, β = 108.09(3)°, γ = 107.92(3)°, V = 1.848 3(6) nm3, Z = 1; Compound 2 crystallized in the triclinic, space group P1̄, a = 1.196 8(2) nm, b = 1.335 4(3) nm, c = 1.4620(3) nm, α = 77.58(3)°, β = 67.97(3)°, γ = 76.12(3)°, V = 2.082 2(7) nm3, Z = 1. The polyanion of compound 1 [Cd(H20)]3[Cd(HPO4) 6(PO4)2(OH)6 (MoO2)i 2]2- is composed of Cd[P4Mo6] 2 dimer and tri-nuclear {Cd3} linkers, which are connected together to form inorganic chains. The polyanion [Mn(H2O) 2]2[Mn(HPO4)6(PO4) 2(OH)6(MoO2)12]3- of compound 2 exhibits a 2D inorganic layer, consisting of Mn[P4Mo 6]2 units linked by the Mn2+ ions. These two kinds of inorganic extended structures are further linked with Hydrogen.

Cd(OAc)_2·2H_2O and MnCl_2·4H_2O were separately introduced to the mixture of MoO_3,H_3PO_4 and bpy. Two new reduced molybdenum phosphate[P_4Mo_6O_(28)(OH)_3]~(9-)({P_4Mo_6}) extended inorganic-organic hybrid supramol-ecular networks(H_2bpy)_2[Cd(H_2O)]_3[Cd(HPO_4)_6(PO_4)_2(OH)_6(MoO_2)_(12)]·5H_2O(1) and(H_2bpy)_3[Mn(H_2O)_2]_2[Mn(HPO_4)_6 (PO_4)_2(OH)_6(MoO_2)_(12)]·10H_2O(2) have been synthesized under hydrothermal techniques.Here,compounds 1 and 2 have been characterized by elementary analyses,IR,TG,and single crystal X-ray diffraction.Compound 1 crystallized in the triclinic,space group P1,a=1.1877(2) nm,b=1.348 5(3) nm,c=1.4108(3) nm,α=106.87(3)°,β=108.09(3)°,γ= 107.92(3)°,V = 1.848 3(6) nm~3,Z = 1;Compound 2 crystallized in the triclinic,space group P1,a = 1.1968(2) nm,b = 1.335 4(3) nm,c = 1.462 0(3) nm,α= 77.58(3)°,β= 67.97(3)°,γ= 76.12(3)°,V = 2.0822(7) nm~3,Z = 1.The polyanion of compound 1[Cd(H_2O)]_3[Cd(HPO_4)_6(PO_4)_2(OH)_6(MoO_2)_(12)]~(2-) is composed of Cd[P_4Mo_6]_2 dimer and tri-nuclear {Cd_3} linkers,which are connected together to form inorganic chains.The polyanion [Mn(H_2O)_2]_2[Mn(HPO_4)_6(PO_4)_2(OH)_6(MoO_2)_(12)]~(3-) of compound 2 exhibits a 2D inorganic layer,consisting of Mn[P_4Mo_6]_2 units linked by the Mn~(2+) ions.These two kinds of inorganic extended structures are further linked with Hydrogen bonds of protonated bpy to construct different 3D supramolecular networks.Simultaneously,the electrochemical property of compound 2 has been explored.

Two novel metal-organic frameworks (MOFs) based on different tetradentate in situ ligands, Cu-3(I)(L-1)(2)(L-2)[(PMo8V4O40)-V-VI-O-V((VO)-O-IV)(2)]center dot 2H(2)O (1) and [(Cu2Cl2)-Cl-I(L-3)] (2) (L-1 = 1,4-bis(imidazol-1-ylmethyl) benzene, L-2 = 1,2,4,5-tetra(4-pyridyl)-benzene L-3 = a-1-hydroxy-e,e,e,e-1,2,4,5-tetra-(4-pyridyl) cyclohexane) have been rationally hydrothermally synthesized and characterized by elemental analyses, IR spectroscopy, TG analyses, and single-crystal X-ray diffraction, respectively. Here, compound 1 represents the first example that dehydrogenative coupling has been employed to yield a novel tetradentate coplanar dye molecule in POM-based MOFs. It also exhibits unique 3D MOFs with two topologies (4(2)8(4))(4(2)8(3)10(1))(8(6))(2) and (4(3)8(3))(4(2)8(4))(4(4)6(2)8(9))(4(10)6(1)8(3)) due to different definitions of nodes. Compound 2 shows a two-fold diagonal/diagonal inclined interpenetration based on Cu-I ions and in situ synthesized ligands L-3. Interestingly, reaction conditions play important roles in the domination of in situ ligands (L-2 and L-3) from the same precursor bpp (bpp = 1,3-bis-(4-pyridyl) propane). Additionally, electrochemical and photocatalysis properties of compound 1 have also been minutely investigated.

Two 2D rhombic grid-like organic–inorganic hybrid compounds [{M(2,2′-bpy)2}2{PMo11VO40}] (M=Cd(1), Zn(2); bpy=2,2′-bipyridine) have been hydrothermally synthesized and characterized by elemental analysis, IR spectroscopy, TG analysis, luminescence spectroscopy, X-ray powder diffraction and single-crystal X-ray diffraction. They are isomorphic and their structures can be considered that the Keggin-heteropolyanion [PMo11VO40]4− are bridged by {M(2,2′-bpy)2} groups through the O–M–O bridges into a 2D covalent network. It is noteworthy that the adjacent layers stack each other to form 3D supermolecular structure via extended C–H⋯O interaction between Keggin-anions and 2,2′-bpy ligands of different layers. Furthermore, the electrochemical behavior of 1-CPE (1-modified carbon paste electrode) and 2-CPE and their electrocatalytic reduction of nitrite were investigated.

One interesting rare earth constructed complex [Ce2(bdc)2(Hbdc)2(H2O)]n·nH2O,has been prepared by hydrothermal reaction and characterized by elemental analysis,IR and single-crystal X-ray diffraction analysis.This compound crystallized in the monoclinic,space group P21/c,a=1.056 1(2) nm,b=1.398 0(3) nm,c=2.162 5(4) nm,β=95.61(3)°,R1=0.041 7,wR2=0.105 4,Z=4,V=3.177 6(11)nm3.This complex is a two-dimensional layer with covalent bonds.

Three new organic–inorganic hybrid compounds H[CuI(dafo)2]3{[CuI(dafo)2]2P2W18O62} · H2O (1), [CuI(dafo)2]3PMo12O40 (2) and [CuI(dafo)2]4SiW12O40 (3) (dafo = 4, 5-diazafluoren-9-one) have been hydrothermally synthesized and characterized by IR, TG and CV. Compound 1 exhibits a 3D supramolecular framework based on weak interactions between bisupported Dawson structure P2W18O62 6− units and copper-complex fragments. With the aid of π–π stacking and hydrogen bonding interactions, a 1D supramolecular framework accommodating polyoxometalate (POM) anions is generated in 2. Compound 3 has similar fundamental units as 2, but the units are assembled in a different way. The distinction of their structures indicates that the POMs are the key factor in determining the frameworks of the final products. The electrochemical properties of these compounds have been studied using bulk-modified carbon paste electrodes.

A Keggin-type Polyoxometalate H2O[Mn(phen)3]2[SiW12O40] was synthesized by mild hydrothermal techniques,and the synthesis and crystal structure were discussed.The compound crystallized in the momoclicnic space group C2/c with a = 1.9735(4)nm,b = 1.8061(4)nm,c = 2.5200(5)nm,α = 90.00°,β = 100.52(3)°,γ = 90.00°,V = 8.831(3)nm3,Z = 4,R1 =0.0562,wR2=0.1376

A new 3-D organic-inorganic hybrid phosphomolybdate, [Ag(bipy)]4(H2P2Mo5O23) 3H2O (1) (bipy = 4,4'-bipyridine) has been hydrothermally synthesized and characterized by elemental analyses, IR, TG, and fluorescent properties. Compound 1 crystallizes in the monoclinic space group C2/c with a = 23.830(5), b = 21.030(4), c = 24.501(5) , = 110.38(3), V = 11510(4) 3, Z = 8, and R1 (wR2) = 0.0507 (0.1210). It contains unique 3-D metal organic frameworks based on silver-complex fragments and hexa-connected P2Mo5 clusters via covalent bonds and represents the highest connection numbers of P2Mo5 clusters to date.

Two new unprecedented Keggin-type polyoxometalate [Cd(phen)_3]_2[PMo~ⅤMo_(11)~ⅥO_(40)] and H_3O[Co(phen)_3]_2[PMo_2~ⅤMo_(10)~ⅥO_(40)] were synthesized at mild hydrothermal condition,and the structure was characterized by elemental analysis,single crystal X-ray diffraction and IR.Compound(Ⅰ) crystallized in the monoclinic,space group P-1,a=1.200 5(2) nm,b=1.327 8(3) nm,c=1.356 7(3) nm,α=103.56(3)°,β=91.37(3)°,γ=97.72(3)°,V=2.079 8(7) nm3,Z=1,R1=0.044 2,wR2=0.140 3.Compound(Ⅱ) crystallized in the monoclinic,space group P-1,a=1.207 9(2)nm,b=1.380 4(3)nm,c=1.442 1(3)nm,α=104.81(3)°,β=109.63(3)°,γ=93.13(3)°,V=2.163 3(8)nm3,Z=1,R1=0.071 7,wR2=0.234 1.

A new 3D supramolecular compound, (4, 4′-bipy) [Ag (4, 4′-bipy)]3 [PMo12 VIO40]·H3O (1) was synthesized under mild hydrothermal condition, and the structure was characterized by elemental analysis, single crystal X-ray diffraction, IR and TGA. Compound 1 exhibits a photoluminescence property at room temperature. The structure of this compound consists of [PMo12O40]3- anion, which is further connected by [Ag (4, 4′-bipy)]3 + unit to form a three-dimensional supramolecular network. Compound 1 crystallized in the triclinic system, space group P1̄, a = 1.1275 (2) nm, b = 1.1910 (2) nm, c = 1.2898 (3) nm, α = 112.63 (3)°, β = 94.63 (3)°, γ = 99.53 (3)°, V = 1.5567 (5) nm3, Z = 1.

A new 3D supramolecular compound, (4,4'-bipy) [Ag(4,4'-bipy)](3)[(PMo12O40)-O-VI]center dot H2O(1) was synthesized under mild hydrothermal condition, and the structure wag characterized by elemental analysis, single crystal X-ray diffraction, IR and TGA. Compound 1 exhibits a photoluminescence property at room temperature. The structure of this compound consists of [PMo12 O-40](3-) anion, which is further connected by [Ag(4,4'-bipy)](3)(+) unit to form a three-dimesional supramolecular network. Compound 1 crystallized in the triclinic system, space group P (1) over bar, a = 1.1275 (2) nm, b = 1.1910 (2) nm, c = 1.2898 (3) nm, alpha = 112.63(3)degrees, beta = 94.63 (3)degrees, gamma = 99.53(3)degrees, V = 1.5567(5) nm(3), Z = 1.