An unprecedented antimonato-polyoxovanadate (SbPOV) based on both α-[V14Sb8O42]4− and β-[V14Sb8O42]4− isomers has been hydrothermally synthesized.

A series of compounds based on vanadate, [Zn(1,10-phen)3][Zn(dap)2]0.5[Zn(dap)2(H2O)]2[VV6VIV10O38Cl]·2H2O (1), [Ni(im)6]3[VV7VIV8O36Cl]·17H2O (2), [Zn(2,2′-bpy)3]2[H2VV10O28]·6H2O (3), [Fe(Phen)3]3[V16O39Cl]·8.5H2O (4), [Zn(2,2′-bpy)]3[V15O36Cl] (5), [Co(2,2′-bpy)]3[V15O36Cl] (6), [Ni(en)2]3[V18O42Cl]·18H2O (7), [Cd(2,2′-bpy)2]2[V4O12]·0.5H2O (8), [Ni(2,2′-bpy)3]2[V4O12]·11H2O (9), [Zn(2,2′-bpy)3][V4O12]·11H2O (10) and [Ni(phen)3]2[V4O12]·12H2O (11) (1,10-phen = 1,10-phenanthroline, dap = 1,2-propanediamine, 2,2′-bpy = 2,2′-bipyridine, im = imidazole), has been synthesized under hydrothermal conditions and characterized using IR, UV-vis, XRD, ESR, elemental analysis and crystal structure analysis. Out of the eleven compounds, 1–3 and 11 are novel. Compound 1 is based on [V16O38Cl]7− anions and [Zn(dap)2]2+ and [Zn(dap)2(H2O)]2+ cations, forming a novel dimer of cluster supported coordination complexes. Compound 2 has a supramolecular structure based on [V15O36Cl]6− anions (V15) and [Ni(im)6]2+ cations. Compound 3 also has a supramolecular structure, which is constructed from [H2V10O28]4− and [Zn(2,2′-bpy)3]2+ cations. Compound 11 is formed by [V4O12]4− clusters and [Ni(phen)3]2+ cations. Compounds 4–10 are also based on vanadate and are not new compounds. Here, we investigate the catalytic properties of these eleven compounds, and the photocatalytic properties of some of these compounds.

Three new organic–inorganic hybrid compounds based on [SiNb12V2O42]12− have been obtained under hydrothermal conditions and characterized by IR, XRD, and single crystal X-ray diffraction analysis. Single crystal X-ray analysis reveals that [Cu(en)2]4[Cu(en)2(H2O)2]2[SiNb12V2O42]·14H2O (1) is constructed from [SiNb12V2O42]12− and two kinds of copper complexes, polyoxoanions in [Cu(en)2]2[Cu(en)2(H2O)]4[SiNb12V2O42]·4H2O (2) and [Cu(en)2(H2O)2]4[Cu(en)2(H2O)]2[SiNb12V2O42]·11H2O (3) are identical to compound 1, but the copper complex combinations of these two compounds are different from that of compound 1. Therefore, the final structures of the three are different from one another. All the three compounds are excellent catalysts for the epoxidation of styrene. In addition, we also synthesized an isopolyniobate K6H2Nb6O19·17H2O (4), which exhibits a 3-D structure constructed from [Nb6O19]8− and potassium clusters.

Five new organic–inorganic hybrid compounds based on [P2W18O62]6− (abbreviated as {P2W18}) and several types of transition metal complexes (TMCs) have been synthesized and characterized by IR, UV-Vis, XRD, cyclic voltammetry measurements and single crystal X-ray diffraction analysis. [Cu(phen)2][Cu(phen)(H2O)3][Cu(phen)2(H2O)][P2W18O62]·8H2O (1) (phen = 1,10-phenanthroline) is a {P2W18} bi-supported complex of phen, while [Cu(2,2′-bpy)(H2O)2]2[Cu(2,2′-bpy)2][P2W18O62]·3.5H2O (2) (2,2′-bpy = 2,2′-bipyridine) is a 1-D chain structure formed by {P2W18} and copper complexes of 2,2′-bpy. [Ag(2,2′-bpy)2]5[HP2W18O62]·H2O (3), [Ag(2,2′-bpy)(H2O)]2[Ag(2,2′-bpy)]2[Ag2(2,2′-bpy)3][P2W18O62] (4), and [Ag(2,2′-bpy)(H2O)]3[Ag2(2,2′-bpy)3][Ag(2,2′-bpy)][P2W18O62]·H2O (5) are constructed from {P2W18} and silver complexes of 2,2′-bpy. Compounds 4 and 5 are novel dimers of {P2W18} joined by silver complexes, while compound 3 contains two different kinds of silver complexes, forming a novel supramolecular structure. Each of the five compounds is formed by {P2W18} and more than one type of TMC. The formation mechanism of these compounds has been carefully discussed. In addition, we also synthesized two supramolecular structures based on {P2W18} and organic moieties: [H6P2W18O62](phen)5.5 (6) and [H6P2W18O62](phen)3·43H2O (7). The catalytic properties of these compounds were also tested.

Five new organic–inorganic hybrid compounds based on different polyoxoanions [HxGeW12O40]n− or [H3As2W18O62]3− (x = 0, 2; n = 4, 2), namely [Cu3(2,2′-bpy)3(inic)(OH)(H2O)][GeW12O40]·1.5H2O (1), [Cu2(phen)2(μ2-Cl)2(inic)]2[H2GeW12O40]·2H2O (2), [Cu2(phen)2(μ2-Cl)Cl(nic)]2[H2GeW12O40] (3), [Cu2(2,2′-bpy)2(hnic)Cl]2[H2GeW12O40] (4), [Cu(phen)(inic)H2O][Cu2(phen)2(inic)2(H2O)][H3As2W18O62]·3H2O (5) (inic = isonicotinic acid, nic = nicotinic acid, hnic = 2-hydroxy-nicotinic acid, 2,2′-bpy = 2,2′-bipyridine, phen = 1,10-phenanthroline), have been synthesized and characterized by IR, UV-Vis, XRD, cyclic voltammetric measurements and single crystal X-ray diffraction analysis. Single crystal X-ray analysis reveals that compound 1 is isomorphous and isostructural with a compound reported by us recently, the main difference between the two is the heteroatom of the polyoxoanions in the two compounds. Compound 2 is a supramolecular structure constructed from polyoxoanions and transition metal mixed-organic-ligand complexes. Compound 3 is a novel polyoxoanion bi-supported transition metal mixed-organic-ligand complex. Compound 4 is a 1-D chain structure constructed from polyoxoanions and transition metal mixed-organic-ligand complexes. The photodegradation properties of compounds 1–5 have been analyzed.

Seven novel compounds based on arsenic–vanadium clusters [Ni(im)(2,2′-bpy)]2[Ni(im)2]2[Ni(2,2′-bpy)][As8V14O42(H2O)] (1), [Ni(2,2′-bpy)3][Ni(im)2]0.5[Ni(2,2′-bpy)(im)][As8V14O42(H2O)] (1a), [Ni(2,2′-bpy)(phen)][Ni(2,2′-bpy)2][As8V14O42(H2O)]·H2O (2) and [Ni(2,2′-biim)(2,2′-bpy)2]2[As8V14O42(H2O)]·6H2O (3), [Cd(2,2′-bpy)(phen)2]2[As8V14O42(H2O)]·4H2O (4), [Cd4(phen)4(ox)(H2O)6][As6V15O42(H2O)]·2H2O (5) and [Co2(phen)4(ox)][H2As8V14O42(H2O)]·(apy)2·2H2O (6) (Him = imidazole, phen = 1,10-phenanthroline, 2,2′-biim = 2,2′-biimidazole, apy = 2-aminopyridine) have been synthesized and characterized by IR, UV-vis, XRD, TG, CD spectrum, elemental analysis and single-crystal X-ray diffraction analysis. Crystal analysis reveals that compound 1 is the first example of a hybrid compound constructed from polyoxometalates and transition metal mixed-organic-ligand complexes of negatively charged nitrogen-containing ligands and neutral nitrogen-containing ligands. Compound 1a is the first example of a POM supported TMC which is formed via arsenic–metal contact. Compound 2 is a chiral compound which exhibits a novel 1-D triple-chain structure constructed from [As8V14O42(H2O)]4− clusters, a type of chiral transition metal mixed-organic-ligand complex and a type of chiral transition metal complex. Compounds 3 and 4 are supramolecular compounds which are formed by [As8V14O42(H2O)]4− clusters and transition metal mixed-organic-ligand complexes, respectively. Compounds 5 and 6 are constructed from arsenic–vanadium clusters and transition metal complexes of nitrogen-containing ligands and oxalic groups. The catalytic properties of compounds 1 and 2–6 have been investigated and we found that the transition metal mixed-organic-ligand complexes have dramatic influences on the catalytic properties of catalysts.

Five new vanadoantimonates [Cd(en)3]3[Sb6V15O42(H2O)]·8H2O (1), [Ni(en)3]2[H2Sb6V15O42(H2O)]·5H2O (2), [Co(en)3]2[H2Sb6V15O42(H2O)]·5H2O (3), [H4Sb8V14O42(H2O)]·5H2O (4) and [Co(enMe)3]2[Sb8V14O42(H2O)]·4H2O (5) (en = ethylenediamine, enMe = 1,2-propanediamine) have been obtained under hydrothermal conditions and characterized by IR, UV-Vis, XRD, ESR and CD spectroscopy. Compound 1 is a chiral compound constructed from [Sb6V15O42(H2O)]6− (Sb6V15) and [Cd(en)3]2+. Compounds 2 and 3 are isostructural and isomorphous. Both compounds are chiral, each of which contains a 2-D inorganic layer formed by [H2Sb6V15O42(H2O)]4−via V–O⋯Sb contacts. Compound 4 contains a 2-D inorganic layer formed by [H4Sb8V14O42(H2O)], of which [H4Sb8V14O42(H2O)] is directed by both V–O⋯Sb and Sb–O⋯Sb interactions. Compound 5 contains a 1-D zigzag chain structure formed by [Sb8V14O42(H2O)]4− (Sb8V14) via Sb–O⋯Sb contacts.

A novel coordination polymer with the chemical formula [Cu4Br(CN)(mtz)2]n (mtz = 5-methyl tetrazole) (1), has been synthesized under solvothermal conditions and characterized by elemental analysis, infrared (IR) spectroscopy, thermal gravimetric analysis, powder X-ray diffraction and single-crystal X-ray diffraction. Interestingly, the Cu(I), CN− and mtz− in compound 1 are all generated from an in situ translation of the original precursors: Cu2+, acetonitrile and 1-methyl-5-mercapto-1,2,3,4-tetrazole (Hmnt). The in situ ring-to-ring conversion of Hmnt into mtz− was found for the first time. Structural analysis reveals that compound 1 is a novel 3D tetrazole-based Cu(I) coordination polymer, containing both metal halide cluster Cu6Br2 and metal pseudohalide cluster Cu2(CN)2 secondary building units (SBUs), which shows an unprecedented (3,6,10)-connected topology. Notably, a pseudo-porphyrin structure with 16-membered rings constructed by four mtz− anions and four copper(I) ions was observed in compound 1. The fluorescence properties of compound 1 were investigated in the solid state and in various solvent emulsions, the results show that compound 1 is a highly sensitive naked-eye colorimetric sensor for NB and 2-NT (NB = nitrobenzene and 2-NT = 2-nitrotoluene).

•A novel two-dimensional (2-D) solid materials with large channels.•A novel –ABAB– stacking mode.•Two different [Ni(en)2]2 + in compound 1.•Antiferromagnetic interactions in compound 1.A novel two-dimensional (2-D) solid material [Ni(en)2]2{SiMoVI8VIV6O42[Ni(en)2]2}·4H2O 1 (en = ethylenediamine) has been hydrothermally synthesized and structurally characterized by IR, UV–Vis spectrum, elemental analysis, XRD, ESR, XPS, X-ray diffraction analysis, magnetic property analysis and electrochemistry study. Single-crystal X-ray analysis reveals that the 2-D framework of compound 1 is based on Mo/V/Si bicapped Keggin clusters interconnected by nickel ethylenediamine complexes. Magnetic susceptibility measurement indicates that compound 1 exhibits antiferromagnetic coupling interactions.A novel two-dimensional (2-D) solid material [Ni(en)2]2{SiMoVI8VIV6O42[Ni(en)2]2}·4H2O 1 (en = ethylenediamine) has been hydrothermally synthesized and characterized.

•Unprecedented 3-D twofold interpenetrating network structure.•First diamondoid framework structure based on POMs and transition metal complexes.•First polymorphs based on As–V POMs.•Different influences of As–V clusters and transition metal complexes on the final structures.Three new compounds based on arsenic–vanadium clusters {[Cu(im)2]4[H2As8V14O42(SO4)]}·H2O (1) and [Cu(phen)(im)]3[Cu(phen)2][As8V14O42(H2O)] (2, 3) (im = imidazole, phen = phenanthroline) have been synthesized and characterized by IR, UV–Vis, XRD, TG analysis, elemental analysis, single-crystal X-ray diffraction analysis and catalytic properties. Crystal analysis reveals that compound 1 shows an unprecedented 3-D twofold interpenetrating network structure with each of the two interpenetrating frameworks exhibiting a novel diamondoid framework structure based on POMs and transition metal complexes. Compounds 2 and 3 are based on identical polyanions and identical transition metal complexes. However, the two compounds are not isomorphous and isostructural with each other. That is to say, the two compounds have an identical chemical formula with different structures: the two are polymorphs of each other. In addition, catalytic properties of compounds 1–3 have been studied.Three novel compounds based on arsenic–vanadium clusters have been synthesized and characterized.

•A new compound based on bi-capped Keggin polyoxoniobates and copper coordination complexes•A novel polyoxoniobate tri-supported coordination complex•Three different types of copper complexes coexist in compound 1.•Polyoxoniobate supports two different types of complexes.A new compound based on bi-capped Keggin polyoxoniobates and copper coordination complexes, with formula [Cu(en)2][Cu(en)2(H2O)2][Cu(en)2(H2O)]2[H4SiNb12V2O42]·7H2O (1) (en = ethylenediamine), was obtained under hydrothermal condition and characterized by single crystal X-ray diffraction, infrared spectrum (IR), powder X-ray diffraction (PXRD), Ultraviolet–visible spectroscopy (UV–vis) and electron spin resonance (ESR) analysis. Compound 1 has three different types of copper complexes in it. A [Cu(en)2]2 + and two [Cu(en)2(H2O)]2 + fragments were supported by the polyoxoniobate to form a novel polyoxoniobate tri-supported coordination complex.A novel polyoxoniobate tri-supported coordination complex has been hydrothermally synthesized and characterized.

Four new organic–inorganic hybrid compounds, namely, [Cu3(4,4′-bpy)3][HSiW12O40]·(C3H4N2) (1), [Cu3(4,4′-bpy)3][PMo12O40]·(C5H6N2)·0.5H2O (2), [Cu2(4,4′-bpy)2][HPMo12O40]·(C5H6N2) (3) and [Cu(Phen)(4,4′-bpy)(H2O)]2[PW12O40]·(4,4′-bpy) (4) (C3H4N2 = imidazole, C5H6N2 = 2-aminopyridine, bpy = bipyridine, Phen = 1,10-phenanthroline), have been synthesized and characterized by IR, UV-vis, powder XRD, cyclic voltammetry analysis, photoluminescence analysis, elemental analyses and single crystal X-ray diffraction. The four compounds represent new examples of secondary organic moiety templated frameworks constructed from Keggin polyanions, metal ions and organic ligands. Compounds 1 and 2 present 3-D framework structures; compound 3 exhibits a 1-D ladder-like structure and compound 4 shows a 2-D layered framework structure. It is noted that the packing structures of compounds 1 and 2 are almost identical; however, the crystal space groups and cell parameters of the two are thoroughly different. Such a phenomenon has also been observed between compound 3 and a compound recently reported by us. Compound 4 is the first framework structure constructed from polyoxometalates, metal ions and mixed organic ligands. In addition, all the four frameworks are combined with dissociated organic moieties as templates.

Six new organic–inorganic hybrid compounds based on [XM12O40]4− (X = heteroatom, M = metal atom), namely [Cu(pic)2][H2XM12O40]·2Hapy·2apy (X = Si, M = W for 1, X = Ge, M = W for 2 and X = Si, M = Mo for 3), [Cu(2,2′-bpy)2][Cu(2,2′-bpy)(H2O)][Cu(pic)2]0.5[XM12O40]·nH2O (X = Si, M = Mo, n = 0.5 for 4, X = Ge, M = W, n = 1 for 5) and [Cu(phen)(H2O)]2[Cu(pic)2][GeW12O40]·2.5H2O (6) (pic = deprotonated picolinic acid, apy = 2-aminopyridine, 2,2′-bpy = 2,2′-bipyridine, phen = phenanthroline), have been synthesized and characterized by IR, UV-Vis, XRD, cyclic voltammetric measurements and single crystal X-ray diffraction analysis. Single crystal X-ray analysis reveals that compounds 1–3 are isomorphous and isostructural, in which each is based on [H2XM12O40]2− and [Cu(pic)2]. Compounds 4 and 5 are also isomorphous and isostructural, of which the structures are more interesting than those of compounds 1–3. Both structures are constructed from [XM12O40]4− and metal mixed–organic–ligand complexes. Compound 6 is also constructed from Keggin ions and metal mixed–organic–ligand complexes, which are, however, thoroughly different from those of compounds 4 and 5. The photodegradation properties of compounds 1–6 have been analyzed. Compounds 1–3 also exhibit rapid absorption properties for RhB (Rhodamine B). Detailed analysis of the photodegradation properties of compounds 1–5 reveals that the molybdate POM has stronger degradation ability for RhB than the tungstate one.

Five new organic–inorganic hybrid compounds based on the Keggin-type polyoxoanion [SiW12O40]4−, namely [Cu3(2,2′-bpy)3(inic)(μ2-OH)(H2O)][SiW12O40]·2H2O (1), [Cu6(phen)6(μ3-Cl)2(μ2-Cl)2Cl2(inic)2][SiW12O40]·6H2O (2), [Cu2(hnic)(2,2′-bpy)2Cl]2[H2SiW12O40] (3), [Cu2(nic)(phen)2Cl2]2[SiW12O40] (4) and [Cu2(pic)(2,2′-bpy)2Cl]2[SiW12O40] (5) (inic = isonicotinic acid, hnic = 2-hydroxy-nicotinic acid, nic = nicotinic acid, pic = picolinic acid, 2,2′-bpy = 2,2′-bipyridine, phen = 1,10-phenanthroline) have been synthesized and characterized by IR, UV-Vis, XPS, XRD, cyclic voltammetric measurements, photoluminescence analysis and single crystal X-ray diffraction analysis. Crystal analysis reveals that compound 1 exhibits a 2-D double layered framework structure constructed from [SiW12O40]4− and copper-aqua-2,2′-bipy-hydroxyl-isonicotinate complexes. Compound 2 is a 0-D discrete structure formed by [SiW12O40]4− and copper-chloro-isonicotinate-phenanthroline complexes. Compound 3 shows a 1-D single chain structure based on the linkage of copper-2,2-bpy-chloro-2-hydroxy-nicotinate complexes and [SiW12O40]4−. Compounds 4 and 5 both contain polyoxometalate supported transition metal complexes, one is a polyoxometalate supported copper-chloro-nicotinate-phenanthroline complex in 4, and the other is a polyoxometalate supported copper-2,2-bpy-chloro-nicotinate complex in 5. It should be noted that nicotinic, isonicotinic and picolinic acids are structural isomers and 2-hydroxy-nicotinic acid is an in situ hydroxylated product of nicotinic acid. In addition, photocatalytic degradation of Rhodamine B (RhB) by compounds 1–5 has been investigated in aqueous solutions.

Six new hybrid compounds based on polyoxometalates and transition metal complexes, [SiW12O40][Ag4(2,2′-bpy)4(4,4′-bpy)3]·2H2O (1), [SiMo12O40][Cu(2,2′-bpy)(H4,4′-bpy)2(H2O)][H4,4-bpy] (2), [PMo12V2O42][Cd2(Phen)2(4,4′-bpy)2(H2O)2(C2O4)]·2H2O (3), [PMo12V2O42][Cu2(4,4′-bpy)2][Cu2(Phen)(4,4′-bpy)2]·3H2O (4), [SiMo12V2O42][Cu2(Phen)2(4,4′-bpy)]2 (5) and [GeMo12V2O42][Cu2(Phen)2(4,4′-bpy)]2 (6) (bpy = bipyridine, Phen = phenanthroline), have been synthesized and characterized. Compound 1 contains a discrete tetranuclear silver-2,2′-bpy-4,4′-bpy complex; compound 2 is the first example where the polyoxometalate supports a metal–aqua–2,2′-bpy-4,4′-bpy complex; it should be noted that the complex contains a 2,2′-bpy and two 4,4′-bpy ligands; compound 3 is the first hybrid compound based on polyoxometalates and metal–aqua–4,4′-bpy–oxalic–phenanthroline complexes; and compound 4 is a novel hybrid compound based on polyoxometalates, extended metal–4,4′-bpy complexes and extended metal–4,4′-bpy–phenanthroline complexes together. Compounds 5 and 6 are isomorphous and isostructural; both exhibit a supramolecular structure constructed from bicapped Keggin POMs and metal–4,4′-bpy–phenanthroline complexes.

•New bi-capped tungsten-based Keggin anion [VVWVI6.5WV3VIV4.5O42]7 −•2-D layer structure formed by bi-capped tungsten-based Keggin anions and TMCs.•Compound 1 shows antiferromagnetic interactions.A new compound, [Cu(en)2(H2O)]{[Cu0.5(en)]3[VVW6.5VIW3VV4.5IVO42Cu(en)2]}·3.5H2O (1) (en = ethylenediamine), has been hydrothermally synthesized and characterized by elemental analysis, IR, ESR, XPS, TG analysis and single-crystal X-ray diffraction analysis. Compound 1 exhibits a novel 2-D structure linked by 1-D infinite left- and right-handed helical chains and transition metal coordination fragments. Adjacent layers are further interconnected into a 3-D supramolecular structure via hydrogen bonds. The magnetic susceptibility of compound 1 demonstrated the presence of antiferromagnetic interactions.[Cu(en)2(H2O)]{[Cu0.5(en)]3[VVW6.5VIW3VV4.5IVO42Cu(en)2]}∙3.5H2O (1) (en = ethylenediamine) exhibits a novel 2-D structure containing unusual 1-D infinite left- and right-handed helical chains linked by transition metal fragments. Adjacent layers are further interconnected into a 3-D supramolecular structure via hydrogen bonds.

Seven new hybrid compounds based on polyoxometalates (POMs) and silver complexes, namely [Ag(2,2′-bpy)3]3{[H2.5BW12O40][Ag(2,2′-bpy)2(H2O)]}2 (1), [Ag(2,2′-bpy)3]3[Ag(2,2′-bpy)2][H2P2W18O62]·6H2O (2), [Ag(2,2′-bpy)3]2[Ag(2,2′-bpy)2][H3PW11AgO39(H2O)]·4.75H2O (3), [Ag(1,10-phen)2]2{[Mo8O26][Ag(1,10-phen)]2} (4), [Ag(2,2′-bpy)3]3[Ag(2,2′-bpy)2]2[H2.5BW12O40]2·(4,4′-bpy)3 (5), [Ag(1,10-phen)2]3[PMo12O40] (6) and [Ag(2,2′-bpy)3]2[H4P2W18O62]·(2,2′-bpy)2·2H2O (7) have been synthesized and characterized. The seven compounds can be classified into four groups based on transition metal complexes and/or dissociated organic moieties in them: (I) compounds based on POMs and two types of silver complexes, compounds 1–4 belong to this group; (II) compounds based on POMs, two types of silver complexes and organic moieties, compound 5 belongs to this group; (III) compounds based on POMs and silver complexes, compound 6 belongs to this group; (IV) compounds based on POMs, silver complexes and organic moieties, compound 7 belongs to this group.Seven new hybrid compounds based on polyoxometalates and silver coordination complexes which can be grouped into four different types have been synthesized and characterized.

A compound containing the first [V16O39Cl]6− (V16O39) polyanion has been hydrothermally synthesized and characterized.

Five hybrid compounds constructed from polyoxometalates, transition metals and organic ligands [Ni2(4,4′-bpy)5(H2O)2][HBW12O40]·5H2O (1), [Ni2(4,4′-bpy)5(Cl)2][H2SiW12O40]·3H2O (2), [Ni2(4,4′-bpy)5(Br)2][H2SiW12O40]·3H2O (3), [SiW12O40]3[Cu2(4,4′-bpy)7]·(H24,4′-bpy)2·4H3O·2H2O (4) and [SiW12O40]3[Cd2(4,4′-bpy)7]·(H24,4′-bpy)2·4H3O·2H2O (5) have been prepared and characterized by IR, UV-vis, XPS, XRD, TG, circular dichroism, second order nonlinear optical (NLO) measurements, photoluminescent measurements and single crystal X-ray diffraction analyses. The X-ray diffraction analyses reveal that the five compounds all exhibit novel framework structures constructed from polyoxometalates, transition metals and organic ligands. The compounds 1, 2, and 3 are isomorphous and compounds 4 and 5 are isomorphous, too. There are two main differences among the first three compounds. The first difference of the three is the central atom of the Keggin ions: it is B atom for compound 1, and Si atom for compounds 2 and 3. The second difference of the three is the monodentate ligand coordinating to the Ni ions: it is water molecule for compound 1, chloride ion for compound 2 and bromide ion for compound 3. The difference between compounds 4 and 5 is the transition metal centre of the frameworks. In addition, compounds 4 and 5 are the first examples of compounds containing both Keggin ion and pseudo-Keggin ion.

•A chain structure formed by copper complexes and bicapped-Keggin-ion-based dimers.•A dimer based on two bicapped-Keggin clusters.•3-D supramolecular strucutre based on hydrogen bonds.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.The first double-supporting bi-capped Keggin dimeric compound, [Cu(en)2][Cu(en)2(H2O)]2[SiMo8V6O42][Cu(en)2]·1.5H2O (1) (en = ethylenediamine), has been synthesized under hydrothermal. Compound 1 exhibits a unique 1-D structure containing dimerized polyoxoanion linked by transition metal coordination fragment. The adjacent chains are further interconnected into a 3-D supramolecular structure via hydrogen bonds.

Highlights•Two novel compounds constructed from Keggin polyanions, metal ions and organic ligands.•Compound 1 shows a 2-D framework structure presenting large pores viewed along the a axis.•Compound 2 exhibits a novel 1-D ladder-like structure.Two new compounds, namely [Cu4(4,4′-bpy)4][SiW12O40]·6H2O (1) and [Cu2(4,4′-bpy)2][SiMo12O40]·(H24,4′-bpy) (2) (bpy = bipyridine), have been hydrothermally synthesized and characterized by IR, UV–Vis, X-ray photoelectron spectroscopy (XPS), powder XRD, elemental analyses and single crystal X-ray diffraction. The two compounds represent new examples of compounds constructed from Keggin polyanions, metal ions and organic ligands. Compounds 1 and 2 both contains Cu(4,4′-bpy)nn+ infinite chains and [SiM12O40]4− anions (M = W for 1 and M = Mo for 2). However, the structures of compounds 1 and 2 are thoroughly different. The Cu(4,4′-bpy)nn+ infinite chains and [SiW12O40]4− anions in compound 1 are connected into a 2-D layered framework structure, and the Cu(4,4′-bpy)nn+ infinite chains and [SiMo12O40]4− anions in compound 2 are linked into a 1-D ladder-like structure.Graphical abstractTwo new compounds, [Cu4(4,4′-bpy)4][SiW12O40]·6H2O (1) and [Cu2(4,4′-bpy)2][SiMo12O40]·(H24,4′-bpy) (2) (bpy = bipyridine), have been hydrothermally synthesized and characterized. Crystal diffraction analyses reveal that the two compounds represent two new examples of compounds constructed from polyoxoanions, metal ions and organic ligands.

Two new compounds [Cu(enMe)2][Cu(enMe)2(H2O)][SiMoV6MoVI6Sb2O40] (1) and [Ni(en)2]2[SiMoV6MoVI6Sb2O40] (2) (enMe = 1,2-diaminopropane, en = 1,2-ethylenediamine) have been hydrothermally synthesized and characterized by IR, UV–Vis spectroscopy, X-ray photoelectron spectroscopy (XPS), powder XRD analyses, elemental analyses and single crystal X-ray diffraction. The two compounds represent the first examples of hybrids based on bi-antimony capped Keggin polyanions {SiMo12Sb2O40} and different transition metal coordination complexes.Graphical abstractThe first compounds constructed from bi-antimony capped Keggin polyoxoanions {SiMo12Sb2O40} and different coordination fragments, namely [Cu(enMe)2][Cu(enMe)2(H2O)][SiMoV6MoVI6Sb2O40] (1) and [Ni(en)2]2[SiMoV6MoVI6Sb2O40] (2) (enMe = 1,2-diaminopropane, en = 1,2-ethylenediamine), have been synthesized and characterized by IR, XPS, XRD, TG, elemental analyses and single-crystal X-ray diffraction. Compound 1 exhibits a zigzag chain structure, while compound 2 presents a supramolecular structure..Highlights► The first compounds formed by {SiMo12Sb2O40} and transition metal complexes. ► Supramolecular compounds based on C–H⋯O and N–H⋯O hydrogen bonds. ► Compound 1 based on {SiMo12Sb2O40} and [Cu(enMe)2]2+ exhibits a chain structure. ► Compound 2 based on {SiMo12Sb2O40} and [Ni(en)2]2+presents a layered structure.

Four new hybrid compounds based on Keggin polyoxometallates and transition metal complexes, [Cu(phen)2]4[GeW12O40] (1), [Cu(bpy)(phen)]2[Cu(bpy)2]3[BW12O40] (2), [Cu(bpy)(phen)][Cu(bpy)2]3[SiW12O40] (3) and [Cu(bpy)2]4[GeW12O40] (4) (phen = 1,10-phenanthroline, bpy = 2,2′-bipyridine), have been hydrothermally synthesized and characterized by IR spectra, UV–Vis, XPS, XRD and single crystal X-ray diffraction analyses. Compounds 1, 2, 3 and 4 are new examples of hybrids based on polyoxometallates and transition metal complexes with a lower positive charge.Four new compounds have been synthesized and characterized. Structure analyses revealed that the four compounds are new examples of hybrids based on polyoxometalates and transition metal complexes with a lower positive charge.

Five new hybrid compounds constructed from polyoxometalates and transition metal coordination complexes with lower positive charge: [PW11CuO39][Cu(bpy)2]5 (1), [BW12O40][Cu(bpy)2]5 (2) [BW12O40][Cu(Phen)2]3[Cu(Phen)(H2O)]2·2H2O (3), [SiW12O40][Cu(bpy)2]4 (4) and [PW12O40][Cu(bpy)2]4 (5) have been prepared and characterized by IR, UV-Vis, XPS, XRD and single crystal X-ray diffraction analyses. The packing motif of the [Cu(bpy)2]+ copper coordination complexes in compound 1 exhibits square supramolecular channels running along the a axis, which are then filled by the [PW11CuO39]5− ions. Compound 2 is isomorphours with compound 1. Compound 3 contains a novel 2-D supramolecular layer structure constructed from [Cu(Phen)2]+ copper coordination complexes through π⋯π interactions. The packing motif of the [Cu(bpy)2]+ copper coordination complexes in compound 4 exhibits a supramolecular channel which is different from compound 1. Compound 5 is isomorphours with compound 4.

Seven new compounds based on polyoxometalates and metal halide clusters have been synthesized and characterized by IR, XPS, UV-vis, XRD, elemental analyses and single crystal X-ray diffraction analyses. Compounds 1, 2, 3 and 4 are hybrids based on polyoxometalates and ennea-nuclear metal halide clusters, which are isomorphous to the compounds we reported recently. Compounds 5–7 are new examples of hybrids based on polyoxometalates and metal halide clusters, of which compounds 5 and 6 are the first examples of hybrids based on polyoxometalates and a new kind of hepta-nuclear metal halide cluster and compound 7 is the first example of hybrid based on polyoxometalates and octakaideca-nuclear metal halide clusters. In addition, compounds 2, 3 and 4 are the first examples of hybrids based on polyoxometalates and metal bromide clusters, and compounds 5 and 6 are the second examples of hybrids based on polyoxometalates and metal iodine clusters. Furthermore, compound 7 is the first example of compounds based on POMs and metal halide extended structures.

Four new supramolecular architectures based on Keggin polyoxometalates (POMs): [(HSiMo12O40)(H4,4′-bpy)2][(H4,4′-bpy)(H2O)2]·2H2O (1), [(HSiW12O40)(H4,4′-bpy)2][(H4,4′-bpy)(H2O)2]·2H2O (2), [(SiW12O40)(H4,4′-bpy)4]·(4,4′-bpy)·2H2O (3) and [H4SiW12O40](2,2′-bpy)4 (4) (bpy = bipyridine) have been prepared hydrothermally and characterized by IR, UV–Vis spectroscopy, X-ray photoelectron spectroscopy (XPS), powder XRD analyses, elemental analyses, fluorescence analysis and single crystal X-ray diffraction analyses. Both compounds 1 and 2 exhibit supramolecular 2D layer structures. Compound 3 exhibits a novel supramolecular double chain structure. Compound 4 contains a 1D chain structure with two 2,2′-bpy ligands as double bridges. It should be noted that compound 4 is the first example of hybrid compound based on 2,2′-bpy ligands and POMs.Graphical abstractFour new supramolecular architectures based on Keggin polyoxometalates have been hydrothermally synthesized and characterized by IR, XPS, XRD, fluorescence analyses, elemental analyses and single-crystal X-ray diffraction analyses.Highlights► Four supramolecular hybrids based on Keggin polyanions. ► Supramolecular hybrid based on 4,4′-bpy and 2,2′-bpy ligands. ► High-dimensional supramolecular networks through different hydrogen bonding interactions. ► The first example of compounds based on 2,2′-bpy ligands and POMs.

Two new organic–inorganic compounds based on polyoxometalates, metal halide clusters and organic ligands: [BW12O40]2[Cu2(Phen)4Cl](H24, 4′-bpy)4·H3O·5H2O (1) and [HPW12O40][Cd2(Phen)4Cl2](4, 4′-bpy) (2) (Phen=1, 10-phenanthroline, bpy=bipyridine), have been prepared and characterized by IR, UV–vis, XPS, XRD and single crystal X-ray diffraction analyses. Crystal structure analyses reveal that compound 1 is constructed from [BW12O40]5−, metal halide clusters [Cu2(Phen)4Cl]+and 4, 4′-bpy ligands, while compound 2 is constructed from [PW12O40]3−, metal halide cluster [Cd2(Phen)4Cl2]2+ and 4, 4′-bpy ligands. Compound 1 and compound 2 are not common hybrids based on polyoxometalates and metal halide clusters, they also contain dissociated organic ligands, therefore, compound 1 and 2 are the first examples of hybrids based on polyoxometalates, metal halide clusters and organic ligands.Graphical AbstractTwo new compounds have been synthesized and characterized. Structure analyses revealed that the two compounds are the first examples of hybrids based on polyoxometalates, metal halide clusters and organic ligands.Highlights► First examples of hybrids based on polyoxometalates, metal halide clusters and organic ligands. ► Two different kinds of metal halide clusters. ► Supramolecular structures based on polyoxometalates, metal halide clusters and organic ligands. ► Hybridization of three different of building blocks.

Four new organic–inorganic hybrid compounds based on bicapped Keggin polyoxometalate {PMo12Sb2O40}: [H24,4′-bpy][PMo12Sb2O40]·6H2O (1), [Him]2[PMo12Sb2O40]·H2O (2), [H3(DABCO)2][PMo12Sb2O40]·2H2O (3) and [Mn(phen)3][PMo12Sb2O40] (4) (bpy = bipyridine, im = imidazole, DABCO = 1,4-diazabicyclo[2,2,2]octane, phen = phenanthroline) have been prepared hydrothermally and characterized by IR, UV–Vis spectroscopy, X-ray photoelectron spectroscopy (XPS), powder XRD analyses, elemental analyses, fluorescence analysis and single crystal X-ray diffraction analyses. The four compounds are new examples of hybrid compounds based on bicapped Keggin polyoxometalate {PMo12Sb2O40}. Compound 1, 2 and 3 are constructed from {PMo12Sb2O40} anions and different organic moieties, respectively. Compound 4 is formed by combining {PMo12Sb2O40} anions and manganese coordination complexes.Graphical abstractFour new members of the family of compounds based on {PMo12Sb2O40} polyoxometalate have been synthesized and characterized by IR, XPS, XRD, fluorescence analyses, elemental analyses and single-crystal X-ray diffraction analyses.Highlights► Four supramolecular hybrids based on {PMo12Sb2O40} polyanions. ► Three supramolecular hybrids based on {PMo12Sb2O40} and different organic ligands. ► One supramolecular hybrid based on {PMo12Sb2O40} and manganese coordination complexes. ► Supramolecular hybrids based on different hydrogen bonding interactions.

Three novel supramolecular compounds [PWVI10.5WV1.5O40][Cu(2, 2′-bpy)2]4.5 (1), [CuI(Phen)2]4[CuI5Cl4(Phen)4][PWVI10WV2O40]2·4H2O(2) and [CuI(Phen)2]4[CuI5Cl4(Phen)4][BWVI12O40]2·2H2O(3) (bpy = bipyridine, Phen = 1,10-Phenanthroline) have been synthesized and characterized by IR, UV-Vis, TG, XRD, elemental analyses and single crystal X-ray diffraction analyses. Compound 1 is the first example of a hybrid compound which is constructed from polyoxometalates and supramolecular noncovalent coordination cages. Both compounds 2 and 3 are constructed from two different types of building blocks: polyoxometalates and metal halide fragments.

Two new hybrid compounds based on Keggin-type polyoxometalates: {[PMo12O40][Ni(Phen)2(H2O)]2}·K·2OH− (1) and [Cd2(Phen)4Cl2][HPW12O40]·H2O (2) (Phen=1,10-phenanthroline), have been prepared and characterized by IR, UV–vis, XPS, XRD and single crystal X-ray diffraction analyses. Compound 1 exhibits a 1-D chain structure constructed from Pseudo-Keggin polyoxometalate bi-supported transition metal coordination complexes linked by K+ ions. Compound 2 contains Pseudo-Keggin polyoxoanions [HPW12O40]2− and novel metal–chloride–ligand coordination complexes [Cd2(Phen)4Cl2]2+.Graphical abstractTwo new hybrid compounds based on different Keggin-type polyoxometalates have been hydrothermally synthesized and characterized by IR, UV-Vis, XPS, XRD, elemental analysis and single crystal X-ray diffraction analysis.Research highlights► Two hybrids based on Pseudo-Keggin polyanions and metal coordination complexes. ► 1-D structure formed by polyanion bisupported metal coordination units linked by K+. ► A metal–chloride–ligand coordination complex [Cd2(Phen)4Cl2]2+. ► A hybrid based on polyanions and metal–chloride–ligand coordination complexes.

Two novel compounds have been hydrothermally synthesized and characterized by IR spectra and single crystal X-ray diffraction analyses. Crystal structure analyses reveal that 1 and 2 exhibit novel 2-D framework structures constructed from tungsten polyoxoanions, metal ions and 4,4-byp units, respectively.

Three novel heteropolyanions [PMo12Sb2O40][Cu(enMe)2]·4H2O (1), [PMo12Sb2O40][Ni(enMe)2]·4H2O (2) and [PMo12Sb2O40][Cu(en)2]·H3O·H2O (3) (enMe = 1,2-diaminopropane, en = ethylene diamine) have been synthesized and characterized by IR spectroscopy, X-ray photoelectron spectroscopy (XPS), thermogravimetric analyses and elemental analyses. Single-crystal X-ray diffraction analyses reveal that these three compounds represent the first examples of compounds based on the novel polyoxoanion {PMo12Sb2O40} and different transition metal coordination complexes. 1 and 2 are isostructural and both exhibit novel 1-D structures. In contrast to 1 and 2, 3 exhibits a substantially distinct novel 1-D structure. In addition, 3 is the first example of an extended structure constructed from polyoxoanions and Cu+ transition metal coordination complexes.

Five novel heteropolyanions have been synthesized and characterized by IR, UV-vis, XPS spectroscopy, XRD, and elemental analyses. Single-crystal X-ray diffraction analyses reveal that these five compounds represent novel examples of compounds based on the combination of polyoxometalates, transition metal coordination complexes and organic amines. Of which 1, 2 and 3 exhibit 0D structures of polyoxometalate supported transition metal coordination complexes, while 4 and 5 exhibit novel 1D structures constructed from polyoxometalates and transition metal coordination complexes.

Two new compounds based on AsIII–VIV polyoxometalates, [HAs6V15O42(H2O)][Cu(enMe)2]2.5·2H2O (1), [H2enMe]2[As8V14O42(H2O)]·3H2O (2), have been hydrothermally synthesized and characterized by IR, UV-vis, ESR, XPS spectra, elemental analyses, magnetic susceptibility studies and single-crystal X-ray diffraction analyses, respectively. X-Ray crystallographic studies reveal that 1 represents the first example of 2D structure constructed from [HAs6V15O42(H2O)]5− anions and transition metal coordination complexes, in addition, it exhibits the first brick-wall-like 2D layer structure constructed from polyoxometalates and transition metal coordination complexes. 2 exhibits a very interesting stacking mode. The study of magnetic susceptibilities demonstrates the presence of antiferromagnetic interactions in both 1 and 2.

Three new supramolecular compounds based on triethylenediamine and different polyoxometalates [WVI3VV3O19H]{[Cu(HDABCO)]2(H2O)} (1), [P2MoVI18O62][HDABCO]2[H2DABCO]2·12 H2O (2) and [MoVI7.5WVI0.5O27][Cu(HDABCO)]2·2 H3O·2 H2O (3) (DABCO=triethylenediamine) have been synthesized hydrothermally and characterized by IR, TG, XPS and X-ray diffraction analyses. Crystal structure analyses reveal that compound 1 exhibits a face-centered cubic packing motif, compound 2 displays a supramolecular structure constructed form the “chains” arranged hexagonally, compound 3 contains [Mo7.5W0.5O27]∞ chain decorated by [Cu(HDABCO)]2+ cations, which was then packed into a layer structure. These results show that the same organonitrogen combining with the different POMs will yield different supramolecular networks.Graphical abstractThree new supramolecular compounds based on triethylenediamine and different polyoxometalates have been hydrothermally synthesized and characterized by IR, XPS, TG, elemental analysis and X-ray diffraction analysis.

A new compound [(BW12O40)Cd(2,2′-bpy)2(H2O)][Cd(2,2′-bpy)3]1.5·0.5H2O (1) has been hydrothermally synthesized and characterized by IR, UV–Vis, XPS spectrum, TG, XRD, elemental analysis and single crystal X-ray diffraction analysis. Crystal structure analysis reveals that 1 is the first Keggin polyoxoanion supported cadmium coordination complex.The first Keggin polyoxometalate supported cadmium coordination complex has been hydrothermally synthesized and characterized by IR, UV-Vis, XPS, TG, XRD, elemental analysis and single-crystal X-ray diffraction analysis.

A novel polyoxometalate [PW11O39Ni(4,4′-Hbpy)]·(4,4′-H2bpy)2·3H2O (1) has been hydrothermally synthesized and characterized by IR, XPS, TG, elemental analysis and single-crystal X-ray diffraction analysis. Crystal structure analysis reveals that 1 is a novel metal coordination fragment derivative of the classic Keggin polyanion.A novel metal coordination fragment derivative of the classic Keggin polyanion has been hydrothermally synthesized and characterized by IR, XPS, TG, elemental analysis and single-crystal X-ray diffraction analysis.

A novel POM compound containing the first Sb bicapped Keggin anion {SiMo12O40Sb2} and two different layers constructed from these anions stacked alternately has already been hydrothermally synthesized.

Two new supramolecular compounds based on tungsten–vanadium polyoxoanions formulated as [Cu(2,2′-bipy)3]2H14[PW2.2V9.8O40(VO)2[Cu(2,2′-bipy)2H2O]2][PW2.2V9.8O40(VO)2]·10H2O (1) and [Cu4(2,2′-bipy)4(H2O)2(PO4)2]H6.5[PW8.4V3.6O40]·2H2O (2) (2,2′-bipy=2,2′-bipyridine) have been synthesized hydrothermally and characterized by IR, TG, XPS and X-ray diffraction analyses. Crystal structure analyses reveal that compounds 1 and 2 exhibit novel 2D supramolecular layer structures constructed from tungsten–vanadium polyoxoanions and different types of secondary building units (SBUs), respectively, the different SBUs are formed by [Cu(2,2′-bipy)2H2O]2+ and [Cu(2,2′-bipy)3]2+ cations in compound 1 and [Cu4(2,2′-bipy)4(H2O)2(PO4)2]2+ cations in 2, respectively. Study of magnetic properties indicated the presence of antiferromagnetic behaviors for both compound 1 and 2.Two new supramolecular compounds were reported. Compounds 1 and 2 exhibit novel 2D supramolecular layer structures constructed from tungsten–vanadium polyoxoanions and different types of secondary building units, respectively.

A novel compound PMo10VIV4IVO42Co(Phen)2(H2O)2PMo10VIV4IVO42Co(Phen)22·2OH-·4,4-bpy1 which represents the missing link between the discrete POMs and the POMs as building blocks in extended structure has already been hydrothermally synthesized and characterized by elemental analysis, IR, UV–Vis, XPS spectrum, TG analysis and single-crystal X-ray diffraction analysis. The study of the magnetic susceptibility of the compound 1 demonstrates the presence of ferromagnetic interactions.A novel compound PMo10VIV4IVO42Co(Phen)2(H2O)2PMo10VIV4IVO42Co(Phen)22·2OH-·4,4-bpy1 which represents the missing link between the discrete POMs and the POMs as building blocks in extended structure has already been hydrothermally synthesized and characterized by elemental analysis, IR, UV–Vis, XPS spectrum, TG analysis, study of the magnetic susceptibility and single-crystal X-ray diffraction analysis.

A novel organic–inorganic hybrid compound [Cu(imi)2]4[γ-Mo8O26] (1) has been synthesized from hydrothermal reaction of imidazone, MoO3·H2O and CuSO4·5H2O in H2O solution and characterized by single-crystal X-ray diffraction analysis. Crystallographic data for 1: monoclinic, space group P2(1)/n, a=12.990(3) Å, b=13.915(3) Å, c=15.049(3) Å, β=108.24(3)°, Z=4, V=2583.4(9) Å3. The compound consists of the first centrosymmetric γ-octamolybdate-supported complex [Cu(imi)2]4[γ-Mo8O26]. TG analysis, IR and XPS spectrum of the compound were also studied.

A novel coordination polymer with the chemical formula [Cu4Br(CN)(mtz)2]n (mtz = 5-methyl tetrazole) (1), has been synthesized under solvothermal conditions and characterized by elemental analysis, infrared (IR) spectroscopy, thermal gravimetric analysis, powder X-ray diffraction and single-crystal X-ray diffraction. Interestingly, the Cu(I), CN− and mtz− in compound 1 are all generated from an in situ translation of the original precursors: Cu2+, acetonitrile and 1-methyl-5-mercapto-1,2,3,4-tetrazole (Hmnt). The in situ ring-to-ring conversion of Hmnt into mtz− was found for the first time. Structural analysis reveals that compound 1 is a novel 3D tetrazole-based Cu(I) coordination polymer, containing both metal halide cluster Cu6Br2 and metal pseudohalide cluster Cu2(CN)2 secondary building units (SBUs), which shows an unprecedented (3,6,10)-connected topology. Notably, a pseudo-porphyrin structure with 16-membered rings constructed by four mtz− anions and four copper(I) ions was observed in compound 1. The fluorescence properties of compound 1 were investigated in the solid state and in various solvent emulsions, the results show that compound 1 is a highly sensitive naked-eye colorimetric sensor for NB and 2-NT (NB = nitrobenzene and 2-NT = 2-nitrotoluene).

A compound containing the first [V16O39Cl]6− (V16O39) polyanion has been hydrothermally synthesized and characterized.

A novel POM compound containing the first Sb bicapped Keggin anion {SiMo12O40Sb2} and two different layers constructed from these anions stacked alternately has already been hydrothermally synthesized.

Three novel heteropolyanions [PMo12Sb2O40][Cu(enMe)2]·4H2O (1), [PMo12Sb2O40][Ni(enMe)2]·4H2O (2) and [PMo12Sb2O40][Cu(en)2]·H3O·H2O (3) (enMe = 1,2-diaminopropane, en = ethylene diamine) have been synthesized and characterized by IR spectroscopy, X-ray photoelectron spectroscopy (XPS), thermogravimetric analyses and elemental analyses. Single-crystal X-ray diffraction analyses reveal that these three compounds represent the first examples of compounds based on the novel polyoxoanion {PMo12Sb2O40} and different transition metal coordination complexes. 1 and 2 are isostructural and both exhibit novel 1-D structures. In contrast to 1 and 2, 3 exhibits a substantially distinct novel 1-D structure. In addition, 3 is the first example of an extended structure constructed from polyoxoanions and Cu+ transition metal coordination complexes.

Two novel compounds have been hydrothermally synthesized and characterized by IR spectra and single crystal X-ray diffraction analyses. Crystal structure analyses reveal that 1 and 2 exhibit novel 2-D framework structures constructed from tungsten polyoxoanions, metal ions and 4,4-byp units, respectively.

Six new organic–inorganic hybrid compounds based on [XM12O40]4− (X = heteroatom, M = metal atom), namely [Cu(pic)2][H2XM12O40]·2Hapy·2apy (X = Si, M = W for 1, X = Ge, M = W for 2 and X = Si, M = Mo for 3), [Cu(2,2′-bpy)2][Cu(2,2′-bpy)(H2O)][Cu(pic)2]0.5[XM12O40]·nH2O (X = Si, M = Mo, n = 0.5 for 4, X = Ge, M = W, n = 1 for 5) and [Cu(phen)(H2O)]2[Cu(pic)2][GeW12O40]·2.5H2O (6) (pic = deprotonated picolinic acid, apy = 2-aminopyridine, 2,2′-bpy = 2,2′-bipyridine, phen = phenanthroline), have been synthesized and characterized by IR, UV-Vis, XRD, cyclic voltammetric measurements and single crystal X-ray diffraction analysis. Single crystal X-ray analysis reveals that compounds 1–3 are isomorphous and isostructural, in which each is based on [H2XM12O40]2− and [Cu(pic)2]. Compounds 4 and 5 are also isomorphous and isostructural, of which the structures are more interesting than those of compounds 1–3. Both structures are constructed from [XM12O40]4− and metal mixed–organic–ligand complexes. Compound 6 is also constructed from Keggin ions and metal mixed–organic–ligand complexes, which are, however, thoroughly different from those of compounds 4 and 5. The photodegradation properties of compounds 1–6 have been analyzed. Compounds 1–3 also exhibit rapid absorption properties for RhB (Rhodamine B). Detailed analysis of the photodegradation properties of compounds 1–5 reveals that the molybdate POM has stronger degradation ability for RhB than the tungstate one.

Five new organic–inorganic hybrid compounds based on the Keggin-type polyoxoanion [SiW12O40]4−, namely [Cu3(2,2′-bpy)3(inic)(μ2-OH)(H2O)][SiW12O40]·2H2O (1), [Cu6(phen)6(μ3-Cl)2(μ2-Cl)2Cl2(inic)2][SiW12O40]·6H2O (2), [Cu2(hnic)(2,2′-bpy)2Cl]2[H2SiW12O40] (3), [Cu2(nic)(phen)2Cl2]2[SiW12O40] (4) and [Cu2(pic)(2,2′-bpy)2Cl]2[SiW12O40] (5) (inic = isonicotinic acid, hnic = 2-hydroxy-nicotinic acid, nic = nicotinic acid, pic = picolinic acid, 2,2′-bpy = 2,2′-bipyridine, phen = 1,10-phenanthroline) have been synthesized and characterized by IR, UV-Vis, XPS, XRD, cyclic voltammetric measurements, photoluminescence analysis and single crystal X-ray diffraction analysis. Crystal analysis reveals that compound 1 exhibits a 2-D double layered framework structure constructed from [SiW12O40]4− and copper-aqua-2,2′-bipy-hydroxyl-isonicotinate complexes. Compound 2 is a 0-D discrete structure formed by [SiW12O40]4− and copper-chloro-isonicotinate-phenanthroline complexes. Compound 3 shows a 1-D single chain structure based on the linkage of copper-2,2-bpy-chloro-2-hydroxy-nicotinate complexes and [SiW12O40]4−. Compounds 4 and 5 both contain polyoxometalate supported transition metal complexes, one is a polyoxometalate supported copper-chloro-nicotinate-phenanthroline complex in 4, and the other is a polyoxometalate supported copper-2,2-bpy-chloro-nicotinate complex in 5. It should be noted that nicotinic, isonicotinic and picolinic acids are structural isomers and 2-hydroxy-nicotinic acid is an in situ hydroxylated product of nicotinic acid. In addition, photocatalytic degradation of Rhodamine B (RhB) by compounds 1–5 has been investigated in aqueous solutions.

Five new organic–inorganic hybrid compounds based on different polyoxoanions [HxGeW12O40]n− or [H3As2W18O62]3− (x = 0, 2; n = 4, 2), namely [Cu3(2,2′-bpy)3(inic)(OH)(H2O)][GeW12O40]·1.5H2O (1), [Cu2(phen)2(μ2-Cl)2(inic)]2[H2GeW12O40]·2H2O (2), [Cu2(phen)2(μ2-Cl)Cl(nic)]2[H2GeW12O40] (3), [Cu2(2,2′-bpy)2(hnic)Cl]2[H2GeW12O40] (4), [Cu(phen)(inic)H2O][Cu2(phen)2(inic)2(H2O)][H3As2W18O62]·3H2O (5) (inic = isonicotinic acid, nic = nicotinic acid, hnic = 2-hydroxy-nicotinic acid, 2,2′-bpy = 2,2′-bipyridine, phen = 1,10-phenanthroline), have been synthesized and characterized by IR, UV-Vis, XRD, cyclic voltammetric measurements and single crystal X-ray diffraction analysis. Single crystal X-ray analysis reveals that compound 1 is isomorphous and isostructural with a compound reported by us recently, the main difference between the two is the heteroatom of the polyoxoanions in the two compounds. Compound 2 is a supramolecular structure constructed from polyoxoanions and transition metal mixed-organic-ligand complexes. Compound 3 is a novel polyoxoanion bi-supported transition metal mixed-organic-ligand complex. Compound 4 is a 1-D chain structure constructed from polyoxoanions and transition metal mixed-organic-ligand complexes. The photodegradation properties of compounds 1–5 have been analyzed.

An unprecedented antimonato-polyoxovanadate (SbPOV) based on both α-[V14Sb8O42]4− and β-[V14Sb8O42]4− isomers has been hydrothermally synthesized.