An ionic crystal assembled by PNb12O40(VO)6 and tris(1,2-diaminopropane)cobalt complexes was hydrothermally isolated and structurally characterized by routine methods. The compound exhibits three-dimensional channels with a pore size of 3.68 Å × 2.30 Å and composed of hydrophilic oxygen atoms of polyanions and hydrophobic −CH3 groups of 1,2-diaminopropane ligands. With increasing vapor pressure, the compound shows preferable adsorption toward water over alcohols, and a gate-opening behavior was deduced from the water adsorption isotherm.

One-pot mechanochemical synthesis was demonstrated to be an efficient strategy to synthesize host–guest POM⊂rho-ZIF complexes (POM = polyoxometalate; rho-ZIF = zeolitic imidazolate framework with rho topology) with high crystallinity. In this work, the metastable rho-ZIF with large interior cavities and windows was used as host matrix for encapsulating and immobilizing bulky guest molecules with high loading efficiency and chemical stability. As novel catalysts, POM⊂rho-ZIF complexes were found effective for the selective oxidation of a series of sulfides to sulfoxides. Moreover, the heterogeneity of these composite catalysts was confirmed by leaching tests, and they can be recycled at least four times without significant loss of activity.

Five inorganic–organic hybrid vanadates based on tetravanadate cores, transition metals and N-donor ligands have been designed and synthesized under hydrothermal conditions, namely, [Zn(eIM)3]2V4O12 (1), [Zn(pIM)3]2V4O12·H2O (2), [Zn(ipIM)3]2V4O12 (3), [Co(eIM)3]2V4O12·H2O (4), [Cu(eIM)2(H2O)]2V4O12 (5) (eIM = 1-ethylimidazole, pIM = 1-propylimidazole, ipIM = isopropylimidazole). All compounds were fully characterized by single-crystal XRD, powder XRD, elemental analysis, TGA, and FT-IR spectroscopy. The hybrid zinc vanadates (1–3) and cobalt vanadate (4) exhibit interesting 2D folded structures and the hybrid copper vanadate (5) presents a 1D chain configuration. All compounds can catalyze olefin epoxidation reactions when using TBHP (TBHP = tert-butyl hydroperoxide) as an oxidant in acetonitrile. The introduction of transition metal ions into tetravanadate cores not only improved the catalytic activity but also fulfilled the heterogeneous catalytic behavior. 1–5 all exhibit extraordinary efficiency in converting olefins to the corresponding epoxides with high conversion and selectivity (particularly, conv. up to 97.1%, sele. up to 100% for 1). Leaching test was also carried out to prove the heterogeneous behavior.By introducing the transitional metal ions of Zn2+, Co2+, Cu2+ into the tetravanadates cores, we obtained five inorganic–organic hybrid vanadates. Compounds 1–5 exhibit much better efficiency in converting olefins to the corresponding epoxides with high conversion and selectivity than the original tetravanadates. More importantly, they also can function as heterogeneous catalysts and be reused without losing their activity.

Three novel inorganic–organic hybrid copper vanadates α-[Cu(mIM)4]V2O6 (1), β-[Cu(mIM)4]V2O6 (2), and [Cu(mIM)2)](VO3)2 (3) (mIM = 1-methylimidazole) have been synthesized by rationally controlling of the hydrothermal conditions and fully characterized by single-crystal XRD, powder XRD, elemental analyses, TGA, and FT-IR spectroscopy. Interestingly, compounds 1 and 2 were isolated as geometric isomers by tuning the solvothermal reaction temperature. Because of the different coordination modes between the tetradentate [V4O12]4– and [Cu(mIM)4]2+ subunits, the supramolecular structures of the two isomers show a 3D framework with an interpenetrating diamond topology for 1 and a 2D network for 2, respectively. Compound 3 was obtained by tuning the reaction temperature and the ratio of mIM/H2O, which showed interesting left- and right-handed helixes with an identical pitch of ca. 5.388 Å in its 2D network structure. As heterogeneous catalysts, compounds 1–3 exhibit excellent catalytic performance in the oxidation of sulfides with H2O2 as oxidant. Among them, the catalytic activity of 1 (conv. up to 98.7%, sele. up to 100%) outperforms others and can be reused without losing its activity. The activity of 1 is also investigated in the oxidation of various alcohols, and excellent results (conv. up to 98.5%, sele. up to 100%) are obtained.

Reaction of two related rigid terpyridine ligands, 4′-(4-cyanophenyl)-4,2′:6′,4-terpyridine (L1) and its derivative, 4′-(4-carboxyphenyl)-4,2′:6′,4-terpyridine (L2), with transition metal ions (Co2+ or Cu2+/Cu+), afforded four novel coordination compounds: Co(L1)Cl2 (1), Co3(L1)3Cl6 (2), CuI9(L1)4.5(CN)9 (3), and [CuII3(L2)6(H2O)6]·4H2O (4). Crystal structure analysis reveals that 1 is comprised of single-stranded 21 helical chains, and weak interactions involving C–H···Cl weak hydrogen bonding and π–π stacking interactions exist in the structure. The structure of 2 is comprised of 32 helices, which is compared with the structure of compound 1. 3 shows a three-dimensional (3D) 4-fold interpenetration structure. 4 exhibits a one-dimensional gridlike belt structure, which further builds 3D supramolecular architecture via π–π stacking interactions. These novel coordination compounds show exceptional catalytic activity for the oxidation of benzylic C–H bonds. Notably, compound 4 shows the best catalytic properties for the oxidation of benzylic hydrocarbons up to 99% conversion and 99% selectivity.

Two novel three-dimensional (3D) extended vanadogermanate-based frameworks, [Co(pdn)2]3[Co2(pdn)4][V16Ge4O44(OH)2(H2O)]·5H2O (1), [Co2(en)3][Co(en)2]2[Co(en)2(H2O)][V16Ge4O44(OH)2(H2O)]·10.5H2O (2), (pdn = 1,2-propanediamine, en = ethylenediamine) have been synthesized under hydrothermal conditions via changing the organic amine. X-ray crystal structure analyses reveal that both frameworks are built of [V16Ge4O44(OH)2(H2O)]10− anions and different Co-amine cations. They represent the first example of incorporating elemental Co into the extended vanadogermanate frameworks. Compound 1 shows a 3D framework with NaCl topology based on {V16Ge4} clusters as nodes, while compound 2 exhibits a 3D (4,6)-connected network with a Schläfli symbol of (46·67·82)2(42·64), which is found for the first time in polyoxovanadate chemistry. The diverse types of metal–organoamine subunits play critical roles in the formation on the final structures. Furthermore, variable temperature susceptibility measurements on compounds 1 and 2 demonstrate the presence of anticipated rare ferrimagnetic behavior.

Two novel extended chains based on rare {VIV15Si6O48} have been prepared under hydrothermal conditions by introducing an organosilicone source into the synthetic system of the polyoxovanadates. Single-crystal X-ray diffraction analyses show that the neighboring {VIV15Si6O48} clusters are linked by a pair of VVO2 fragments via the coordination bonds of (Si–)O–V–O(–Si) to give rise to a zig-zag chain in compound 1, which is the first example of V(IV,V) mixed valence states successfully synthesized in {V15Si6O48}-containing POMs. While in 2 the linkages are changed to [Co(pdn)2(H2O)]2+ (pdn = 1,3-propanediamine) cations instead of {VVO2} fragments, to generate another comparable 1-D infinite chain, which demonstrates the first organic-inorganic vanadosilicon hybrid linked by a second transition-metal complex. The possible hydrolysis mechanism of tetraethyl orthosilicate as the Si source is postulated to afford a feasible protocol to synthesize a new type of vanadosilicate cluster. The magnetic properties of the two compounds have also been investigated.

The first organic–inorganic hybrid vanadoniobate cluster compounds with a bicapped Keggin-type {VNb12O40(VO)2} core have been synthesized and characterized.

Two novel polyoxotantalate derivatives, {[Cu(1,3-dap)2]2[Cu(1,3-dap)(H2O)]2[Ta6O19]}·8H2O (1) and [Cu(en)2]4[Ta6O19]·14H2O (2) (1,3-dap = 1,3-diaminopropane, and en = ethylenediamine), which are constructed from the Lindqvist-type [Ta6O19]8− anion and copper–amine complexes, have been synthesized and characterized by elemental analyses, IR, XPS, TGA and single-crystal X-ray diffraction. In compound 1, each [Ta6O19]8− anion is bound to four copper fragments via the surface bridging oxygen atoms to form a neutral tetrasupported Lindqvist structure, which is further connected by water trimer via hydrogen-bonds to yield a one-dimensional (1D) supramolecular chain. In compound 2, the [Ta6O19]8− anions are linked together via the hydrogen bonds and Cu⋯O weak interaction to form an infinite 1D supramolecular chain, which is further connected to each other via hydrogen bonds with the cyclic water tetramer to yield a two-dimensional (2D) supramolecular network.The [Ta6O19]8− anions in 2 are connected by Cu⋯O weak interactions and extensive OH⋯O hydrogen-bonding interactions to form a 2D supramolecular network.Research highlights► Transition metal complexes were first introduced into the system of polyoxotantalates. ► 1 represents the first hexatantalate coordinated with four copper–amine complexes. ► There exist water trimer and water tetramer in 1 and 2, respectively. ► There are extensive hydrogen bonds between water clusters and polyanions in 1 and 2.

A novel homochiral 3D copper(II)-organic framework has been synthesized under solvothermal reaction. Single-crystal X-ray diffraction reveals it features a fascinating 3D cationic framework with SO42− and water molecule occupying its central of channel. Moreover, the unique triple-stranded helices in the structure based on tetranuclear CopperII Cluster Node are further linked by the UCA ligand (UCA = Urocanic acid) and give rise to the resultant homochiral network, which can be described as a rarely observed 4966 topology.A novel homochiral 3D copper(II)-organic framework has been synthesized under solvothermal reaction. It features a fascinating 3D cationic framework with SO42- and water molecule occupying its central of channel. Moreover, the unique triple-stranded helices in the structure based on tetranuclear CopperII Cluster Node are further linked by the UCA ligand (Urocanic acid) and give rise to the resultant homochiral network in a rarely observed 4966 topology.

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.Two types of new inorganic–organic hybrid frameworks through incorporation of Keggin-type heteropolyanion [SiW12O40]4− within the voids of lanthanides-pdc network as pillars or guests under hydrothermal condition were successfully assembled. Solid-state properties of compounds 1 and 2a such as thermal stability and photoluminescence have been further investigated.

Two novel organic–inorganic hybrid vanadoantimonate compounds, [Zn2(dien)3][{Zn(dien)}2V16Sb4O42(H2O)]·4H2O (1) and [Zn(dien)2]2 [{Zn(dien)}2(V14Sb8O42)2(H2O)]·4H2O (2) (dien = Diethylenetriamine), have been synthesized hydrothermally at different pH value, and structurally characterized by elemental analyses, FT-IR, XPS, TGA and single crystal X-ray diffraction analysis. Compound 1 is composed of the rare [V16Sb4O42]8− cluster covalently linked by two [Zn(dien)]2+ coordination cations to yield a novel one-dimensional linear chain. Compound 2 exhibits a one-dimensional zigzag chain constructed from the [V14Sb8O42]4− cluster and [Zn(dien)]2+ coordination polymer. The two examples represent the first one-dimensional assemblies based on vanadoantimonate cluster and the metal–organic complex moieties.

Two novel 3D extended polyoxotantalates/niobates solid complexes: [Na6(H2O)13)][Li(H2O)(H3O)][(Ta6O19)] (1) and [Na6(H2O)13][Li(H2O)2][H(Nb6O19)] (2) have been assembled successfully based on double alkali metal ions (Li+ and Na+) and Lindqvist clusters ([Ta6O19]8−/[Nb6O19]8−) under aqueous solution. Both compounds have been characterized by IR, TG analysis and single-crystal X-ray diffraction. It is worth noting that Li and Na ions, different kinds of alkali ions, are first observed coexisting in two resultant solid crystal structures of polyoxotantalates/niobates. Further photocatalytic investigations show that methylene blue (MB) dye solution can be degraded by UV irradiation effectively in the presence of [Nb6O19]8−/[Ta6O19]8−. The experiments indicate that the degradation efficiency depends on pH value, irradiation time, initial MB concentration and different types of POM anions etc.

Two novel extended chains based on rare {VIV15Si6O48} have been prepared under hydrothermal conditions by introducing an organosilicone source into the synthetic system of the polyoxovanadates. Single-crystal X-ray diffraction analyses show that the neighboring {VIV15Si6O48} clusters are linked by a pair of VVO2 fragments via the coordination bonds of (Si–)O–V–O(–Si) to give rise to a zig-zag chain in compound 1, which is the first example of V(IV,V) mixed valence states successfully synthesized in {V15Si6O48}-containing POMs. While in 2 the linkages are changed to [Co(pdn)2(H2O)]2+ (pdn = 1,3-propanediamine) cations instead of {VVO2} fragments, to generate another comparable 1-D infinite chain, which demonstrates the first organic-inorganic vanadosilicon hybrid linked by a second transition-metal complex. The possible hydrolysis mechanism of tetraethyl orthosilicate as the Si source is postulated to afford a feasible protocol to synthesize a new type of vanadosilicate cluster. The magnetic properties of the two compounds have also been investigated.

Two novel three-dimensional (3D) extended vanadogermanate-based frameworks, [Co(pdn)2]3[Co2(pdn)4][V16Ge4O44(OH)2(H2O)]·5H2O (1), [Co2(en)3][Co(en)2]2[Co(en)2(H2O)][V16Ge4O44(OH)2(H2O)]·10.5H2O (2), (pdn = 1,2-propanediamine, en = ethylenediamine) have been synthesized under hydrothermal conditions via changing the organic amine. X-ray crystal structure analyses reveal that both frameworks are built of [V16Ge4O44(OH)2(H2O)]10− anions and different Co-amine cations. They represent the first example of incorporating elemental Co into the extended vanadogermanate frameworks. Compound 1 shows a 3D framework with NaCl topology based on {V16Ge4} clusters as nodes, while compound 2 exhibits a 3D (4,6)-connected network with a Schläfli symbol of (46·67·82)2(42·64), which is found for the first time in polyoxovanadate chemistry. The diverse types of metal–organoamine subunits play critical roles in the formation on the final structures. Furthermore, variable temperature susceptibility measurements on compounds 1 and 2 demonstrate the presence of anticipated rare ferrimagnetic behavior.

The first organic–inorganic hybrid vanadoniobate cluster compounds with a bicapped Keggin-type {VNb12O40(VO)2} core have been synthesized and characterized.