Two new mixed-metal clusters {CuM2(H2O)2[Cu(C14H16N2O3)Cl]6}·H2O (M = Mn 1, Zn 2) based on Schiff-base ligands were designed and synthesized by the reaction of 1,2-cyclohexanediamine-N,N′-bis-(3-carboxylsalicylide), copper chloride and zinc chloride or manganese chloride under solvothermal conditions. They were characterized by various techniques including single-crystal X-ray diffraction, powder X-ray diffraction (XPRD), elemental analysis, TG analysis, IR and UV-visible spectroscopy. Compounds 1 and 2 are isostructural, and display an interesting windmill-type structure built from a trinuclear mixed-metal center [CuM2(CO2)6(H2O)2] (M = Mn 1, Zn 2) linked with six [CuLCl] (L = C14H16N2O3) units. The oxidation of cyclohexene catalysed by 1 and 2 as heterogeneous catalysts was investigated and showed high activity. In addition, a magnetic study indicates that antiferromagnetic interactions exist in compound 1.

•A rare example of organic-inorganic hybrid based on [Mn2V22O64]10 − polyoxoanion has been synthesized.•A three-dimensional supramolecular structure is formed in the hybrid through hydrogen bond.•The hybrid exhibits high activity in the oxidation of sulfide.A new organic-inorganic hybrid compound constructed from [Mn2V22O64]10 − units, H6[(C6H4NO2Cu(H2O)4)]2[Mn2V22O64]·28H2O 1, has been synthesized and characterized by single-crystal X-ray diffraction, IR, powder X-ray diffraction (XPRD) and TG. Compound 1 is composed of dimeric [Mn2V22O64]10 − polyoxoanions, metal-organo fragments [(C6H4NO2Cu(H2O)4)]2 + and lattice water molecules. Moreover, a three-dimensional supramolecular structure is formed in 1 by the extensive hydrogen bond interaction among the terminal oxygen atoms of [Mn2V22O64]10 − anions, the coordinated waters of Cu2 + ions and crystal water molecules. Compound 1 exhibits remarkable catalytic activity for the heterogeneous oxidation of sulfides under mild condition.A new organic-inorganic hybrid compound constructed from [Mn2V22O64]10 − units, H6[(C6H4NO2Cu(H2O)4)]2[Mn2V22O64]·28H2O, has been synthesized and it exhibits remarkable catalytic activity for the heterogeneous oxidation of sulfides under mild condition.

•The catalyst is a rare example of surfactant-encapsulated POMs formed by high-nuclear poly-{HPMo6} POMs.•The removal of sulfide could reach above 98% under the optimal conditions.•The catalyst can be reused 5 times with high recycling efficiency.Two novel surfactant-encapsulated high-nuclear polyoxometalates catalysts (DODA)20[(HPMo6O21)4(O2CCH2CO2)6]·27H2O and (DODA)10[(HPMo6O21)2(C2O4)3]·11H2O have been prepared and characterized by TG, FT-IR, 1H NMR and UV–Vis. They were used for the oxidative desulfurization of model oil containing sulfur compounds such as dibenzothiophene (DBT), 4,6-dimethyldibenzothiophene (4,6-DMDBT), benzothiophene (BT) with H2O2 as an oxidant under mild conditions. The removal of DBT, 4,6-DMDBT and BT could reach above 98% under the optimal conditions of n(S)/n(catalyst)/n(H2O2) = 220:1:880 at 60 °C for 2.5 h, 4.5 h and 5 h respectively, which improved to be a promising catalyst in the ODS process. The oxidative reactivity of the sulfur-containing compounds decreased according to DBT > 4,6-DMDBT > BT. We investigated the main factors affecting the process including temperature, the polymeric structures of catalysts, and O/S (H2O2/DBT) molar ratio in detail. Moreover, the catalyst can be reused 5 times with high recycling efficiency.Two new surfactant-encapsulated high-nuclear polyoxometalate catalysts composed of the poly-{PMo6} POMs, (DODA)20[(HPMo6O21)4(O2CCH2CO2)6]·27H2O (SEP-1) and (DODA)10[(HPMo6O21)2(C2O4)3]·11H2O (SEP-2), have been synthesized, and used as catalysts for the oxidative desulfurization of model oil with H2O2 as an oxidant. The removal of sulfide could reach above 98% under the optimal conditions.

A family of polyoxometalate compounds based on 1:13 polyoxoanions [MnV13O38]7–, organic molecules, and lanthanide cations, H[{La2(DMF)5(H2O)4}{MnV13O38}]·DMF·5H2O (1), H[{Ce2(DMF)2(H2O)7}{MnV13O38}]·0.5DMF·5.5H2O (2), H2[{K(H2O)2}2{Nd(DMF)(H2O)3}{MnV13O38}]·5H2O (3), H[{Ln2(C6H5NO2)3(H2O)6}{[MnV13O38}]·C6H5NO2·10H2O (Ln = La 4, Ce 5), and H2.5[{Pr(C6H5NO2)(H2O)3.5}{Pr0.5(H2O)2}{MnV13O38}]·0.5C6H5NO2·10H2O (6) (DMF = N,N-dimethylformamide; C6H5NO2 = isonicotinic acid), have been obtained utilizing a conventional method of aqueous solution and further characterized by elemental analysis, IR spectrum, UV spectrum, thermogravimetric analysis, and single-crystal X-ray diffraction. Compounds 1 and 2 exhibit a one-dimensional extended chain structure constructed by [MnV13O38]7– and lanthanide-organic coordination linkage, while compound 3 reveals three-dimensional (3D) open framework formed by polyoxoanion-lanthanide chains and potassium cations. Compounds 4–6 exhibit 3D supramolecular framework architectures based on [MnV13O38]7– polyoxoanions and lanthanide-organic coordination units. These compounds represent the first examples of extended organic–inorganic hybrids built up by [MnV13O38]7– building blocks and rare earth cations. The influences of the lanthanide contraction effect on the structural alterations from 1 to 3 and from 4 to 6 have been disscussed. The electrochemical and electrocatalytic properties for compounds 1–6 have been studied. Magnetic studies indicate that antiferromagnetic interactions exist in compounds 1–6.

•1 represents a rare example of homometallic salen-based MOFs.•The synthesis method is simplified to one step without the pre-metalation process.•The fluorescence spectra prove the influence of structure on the property.Two new homometallic coordination polymers 1 and 2 have been prepared by the directly one-step hydrothermal reactions of a carboxylate-functionalized salen ligand with Zn(II) and Co(II) ions, respectively. 1 exhibits a 3D open framework built by [Zn4(μ4-O)(carboxylate)8] units and double Zn-salen ligands, while 2 shows a 1D chain structure constructed by cobalt ions and the ligand derived from the hydrolysis to one CN bond of salen ligand. The preliminary fluorescence measurements of 1–2 show the influence of structure on the property.Two new homometallic coordination polymers 1 and 2 have been prepared by the directly one-step hydrothermal reactions of a carboxylate-functionalized salen ligand with Zn(II) and Co(II) ions, respectively. 1 exhibits a 3D open framework, while 2 shows a 1D chain structure derived from the hydrolysis of salen ligand.

•The 3D framework of 1 possesses both hydrophobic and hydrophilic channels.•1 can reversibly transform to 2 upon SCSC process.•Both 1 and 2 were indicated the presence antiferromagnetic interactions.A new metal–organic framework (MOF) [Cu5(pz)2(μ3-OH)2(bdc)2(Hbdc)2]·8H2O (1) possessing both hydrophobic and hydrophilic channels has been prepared by two synthetic methods which have subtle differences. Interestingly, 1 can reversibly transform to a layered coordination polymer Na{[(Cu3(pz)3(μ3-OH)]2(bdc)2(Hbdc)}·DMF·21H2O (2) upon a single-crystal to single crystal (SCSC) process. 1 exhibits an 8-connected three-dimensional (3D) framework constructed by pentanuclear copper units and bdc linkers, while 2 shows a two-dimensional (2D) network built by triangular trinuclear copper units and bdc linkers. Furthermore, the magnetic properties of both 1 and 2 have been studied.There are two methods to implement the metal–organic framework 1 possessing both hydrophobic and hydrophilic channels, but only one way can achieve the reversible single-crystal to single-crystal transformation from 1 to a layered coordination polymer 2, which cannot be accomplished directly.

Purely inorganic porous frameworks using catalytically active [MnV13O38]7− clusters as nodes and rare earth ions as linkers have been successfully prepared. The POM-based porous framework is a kind of multifunctional material, which exhibits selective adsorption behavior and remarkable catalytic activity for the heterogeneous oxidation of sulfides.

Three trimeric polyoxovanadate based on 1:13 anions [MnV13O38]7− with lanthanide cations Ln3+ (Ln = La, Ce and Nd) and pyridine-3-carboxylic acid: HK3{[Ln(H2O)4]6[MnV13O38]3(SO4)2}·3(C6H6NO2)·nH2O (Ln = La 1, Nd 3; n = 33 for 1, 20 for 3), H2.5K1.5{[Ce(H2O)4]6[MnV13O38]3(SO4)2}·3(C6H6NO2)·20.5H2O (2) (C6H5NO2 = pyridine-3-carboxylic acid) have been synthesized and characterized by elemental analysis, IR spectroscopy, UV spectroscopy, TG analysis, XPRD, electrochemical analyses, magnetism and single-crystal X-ray diffraction. Compounds 1–3 are isostructural and crystallized in the hexagonal system, space group P63/m. Compounds 1–3 contain an unusual trimeric polyoxoanion [{Ln2MnV13O38}3(SO4)2]7−, representing the first polyoxovanadate-based trimeric aggregate with rare earth ions. The electrochemical and electrocatalytic properties of the compounds have been investigated. Magnetic studies indicate that antiferromagnetic interactions exist in the compounds.

•Two new MOFs based on Cu12 units were synthesized and characterized.•1 and 2 represent the rare examples of MOFs constructed by cyclic type SBUs.•1 and 2 exhibit photocatalytic activity for the degradation of RhB.Two new metal–organic frameworks based on cyclic-type dodecanuclear copper units, (Me4N)6[Cu12(OMe)6(pz)6(BTC)6]·18H2O 1 and (Me4N)6[Cu12(OH)6(pz)6(BTC)6]·21H2O 2 (pz = pyrazolate, BTC = 1,3,5-benzenetricarboxylate), have been prepared by the solvothermal reactions of copper salts, Hpz and H3BTC ligands. The cyclic-type Cu12 unit in 1 and 2 is constructed by twelve CuII ions linked together by μ2-OH or μ2-OMe and unidentate carboxylate groups at the inner- and μ-pz and bidentate carboxylate groups at the outer surface of the toroid. In 1 and 2, each Cu12 unit is connected to 12 other units by BTC linkers, leading to 12-connected three-dimensional porous frameworks. The photocatalytic investigations indicate that compounds 1 and 2 exhibit photocatalytic activity for the degradation of RhB.Two new 12-connected MOFs based on dodecanuclear copper units were synthesized and characterized.

A 12-connected metal–organic framework based on an unprecedented cyclic Cu12 cluster with a large internal cavity has been prepared, and its cation exchange property was determined.

A new metal–organic framework based on hexanuclear copper units, Cu6(μ3-O)(μ3-OH)(pz)6(btc) (pz = pyrazolate, btc = 1,3,5-benzenetricarboxylate) 1, has been prepared by the hydrothermal reaction of Cu2 + ions, Hpz and H3btc ligands in a methanolic solution. The hexanuclear copper building unit in 1 is composed of two triangular Cu3O(H)(pz)3 units bridged by carboxyl groups, in which each Cu center is coordinatively unsaturated with open coordination sites. The photocatalytic investigation indicates that compound 1 exhibits a higher photocatalytic activity for the degradation of Rhodamine B.A new MOF based on hexanuclear copper units was synthesized and structurally characterized as a (3,3)-connected network.Highlights► A new MOF based on hexanuclear copper units was synthesized and characterized. ► The first example of MOFs based on Cu6 unit constructed by two Cu3(μ3-O) units. ► Each copper center is coordinatively unsaturated with open coordination sites. ► Compound 1 exhibits higher photocatalytic activity for the degradation of RhB.

Three new Fe-containing MOFs, H3O[Fe5(BTC)3(OAc)2(DMF)2]·H2O 1, [FeNa(m-BDC)2]·NH2(CH3)22 and [N(CH3)4]2[Fe3(HBTC)(BTC)2(H2O)]·5.5H2O 3 (BTC = 1,3,5-benzenetricarboxylate, m-BDC = 1,3-benzene-dicarboxylate), have been synthesized from the solvothermal reactions of iron salts and carboxylate ligands. The framework of 1 is constructed from two kinds of secondary building units (SBUs): the sinusoidal chain of iron octahedra SBU [Fe2(COO)6]n2n− and paddle-wheel SBU [Fe2(COO)4(DMF)]. Compound 1 represents the first example of Fe-containing MOFs constructed from two kinds of SBUs. The framework of 2 is built from zigzag-chain SBUs [FeNa(COO)6]n3n− and m-BDC linkers. The framework of 3 is formed by linear tri-nuclear iron SBUs [Fe3(COO)8(H2O)]2− and triangular BTC linkers. To our knowledge, the Fe-containing sinusoidal chain SBU in 1, zigzag-chain SBU in 2 and linear tri-nuclear iron SBU in 3 are found in Fe-containing MOFs for the first time. Magnetic investigation indicates the present of antiferromagnetic exchange interaction within the iron units of compounds.Graphical abstractThree new metal–organic frameworks with FeII-containing SBUs, namely, H3O[Fe5(BTC)3(OAc)2(DMF)2]·H2O (1), [FeNa(m-bdc)2]·NH2(CH3)2 (2) and [N(CH3)4]2[Fe3(Hbtc)(btc)2(H2O)]·5.5H2O (3) have been solvothermal synthesized and characterized by elemental analysis, IR spectroscopy, thermal gravimetric analysis (TG), UV analysis and single-crystal X-ray diffraction. The magnetic properties of these three compounds have also been investigated.Highlights► MOFs with two kinds of SBUs were synthesized. ► Hybrid compounds built up from inorganic chain-like SBUs instead of clusters. ► Iron complexes display a range of antiferromagnetic exchange interaction.

The visible light photocatalytic H2 evolution activities of a series of transition-metal substituted Keggin-structure heteropoly blues K6SiW11O39M(H2O)·nH2O (M = Co, Ni, Cu and Zn) were systematically studied with Pt nanoparticles as co-catalyst. The H2 evolution rates were 150, 98, 65 and 48 μmol h−1g−1 for SiW11Cu, SiW11Ni, SiW11Co and SiW11Zn, respectively, meaning that the order of photocatalytic activity of these heteropoly blues from transition-metal substituted polyoxometalates was: SiW11Cu > SiW11Ni > SiW11Co > SiW11Zn. The catalysts could be efficiently reused for at least 5 cycles.

Two organic–inorganic 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)}n2n+ 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.

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.

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.

A new Ni12 cluster based on polyoxometalate ligands [Ni12(OH)9WO4(W7O26(OH))(PW9O34)3]25− (1) has been assembled in aqueous solution containing [PW9O34]9−, WO42−, and NiCl2·6H2O. The Ni12 core in 1 shows a unique three-petal flower-shaped structure composed of three Ni4 cubane units. Magnetic investigation indicates the presence of dominantly ferromagnetic interactions within the Ni12 core.

Three trimeric polyoxovanadate based on 1:13 anions [MnV13O38]7− with lanthanide cations Ln3+ (Ln = La, Ce and Nd) and pyridine-3-carboxylic acid: HK3{[Ln(H2O)4]6[MnV13O38]3(SO4)2}·3(C6H6NO2)·nH2O (Ln = La 1, Nd 3; n = 33 for 1, 20 for 3), H2.5K1.5{[Ce(H2O)4]6[MnV13O38]3(SO4)2}·3(C6H6NO2)·20.5H2O (2) (C6H5NO2 = pyridine-3-carboxylic acid) have been synthesized and characterized by elemental analysis, IR spectroscopy, UV spectroscopy, TG analysis, XPRD, electrochemical analyses, magnetism and single-crystal X-ray diffraction. Compounds 1–3 are isostructural and crystallized in the hexagonal system, space group P63/m. Compounds 1–3 contain an unusual trimeric polyoxoanion [{Ln2MnV13O38}3(SO4)2]7−, representing the first polyoxovanadate-based trimeric aggregate with rare earth ions. The electrochemical and electrocatalytic properties of the compounds have been investigated. Magnetic studies indicate that antiferromagnetic interactions exist in the compounds.

A 12-connected metal–organic framework based on an unprecedented cyclic Cu12 cluster with a large internal cavity has been prepared, and its cation exchange property was determined.

Purely inorganic porous frameworks using catalytically active [MnV13O38]7− clusters as nodes and rare earth ions as linkers have been successfully prepared. The POM-based porous framework is a kind of multifunctional material, which exhibits selective adsorption behavior and remarkable catalytic activity for the heterogeneous oxidation of sulfides.