Polynuclear complexes of main group and transition metals with polyaminopolycarboxylate and polyoxometalate

Six supramolecular compounds constructed by main group and transition metals, polyoxotungstates (SiW(12)O(40)(4-)) and trans-N,N,N',N'-1,2-cyclohexanediaminotetraacetic acid (H(4)CyDTA), (NH(4))(3)[Ni(4)Na(H(2)O)(10)(CyDTA)(2)][SiW(12)O(40)]·10H(2)O (1) (NH(4))(2)[Cu(3)Na(2)(HCyDTA)(2)(H(2)O)(13)][SiW(12)O(40)]·5H(2)O (2), (NH(4))(2)[Zn(5)(CyDTA)(2)(H(2)O)(16)][SiW(12)O(40)]·8H(2)O (3), (NH(4))(4)[Cd(4)(CyDTA)(2)(H(2)O)(8)][SiW(12)O(40)]·6H(2)O (4), (NH(4))(4)[Sr(3)(HCyDTA)(2)(H(2)O)(14)][SiW(12)O(40)]·2H(2)O (5) and [Ca(4)(H(2)CyDTA)(2)(H(2)O)(22)][SiW(12)O(40)]·8H(2)O (6), were synthesized in aqueous solution and characterized by IR spectroscopy, thermogravimetric analysis and single-crystal X-ray diffraction techniques. Single-crystal structure analyses indicate they are constructed by the complexes with different nuclearity and polyoxometalates. In the sequence of Ni, Cu, Zn the nuclearity of the homometallic complex units increases from 2 to 5. Cadmium ions gives a tetranuclear complex with a compact structure. In 5 and 6 the main group metal ions and CyDTA form polymeric chains. CyDTA exhibits rather different coordination patterns to main group metal ions and transition metal ions due to their ionic radii and electronic configuration. The complex units and polyoxometalates arrange in different patterns due to the different shapes of the complex units. The compounds exhibit different thermal decomposition processes and the formation of compounds 3 and 4 quenches ligand-centered emissions and gives a ligand-to-metal emission. The study on various temperature susceptibilities of 1 and 2 shows that there is an antiferromagnetic coupling in the two compounds but coupling patterns are different.     

Inorganic-organic hybrid materials with different dimensions constructed from copper-fluconazole metal-organic units and Keggin polyanion clusters

Inorganic-organic hybrid materials based on Keggin polyoxometalate building blocks combined with Cu(II)/Cu(I) and flexible fluconazole ligand [1-(2,4-difluorophenyl)-1,1-bis[(1H-1,2,4-triazol-1-yl)methyl]methanol] (Hfcz) have been obtained by hydrothermal methods, namely, [Cu(II)(2)(Hfcz)(4)(SiW(12)O(40))].3H(2)O (1), [Cu(II)(4)(fcz)(4)(H(2)O)(4)(SiMo(12)O(40))].6H(2)O (2), [Cu(II)(2)(fcz)(2)][Cu(II)(4)(fcz)(4)(SiW(12)O(40))][Cu(II)(2)(fcz)(2)(H(2)O)(2)(SiW(12)O(40))].6H(2)O (3), (Et(3)NH)(2)[Cu(I)(2)(Hfcz)(2)(SiW(12)O(40))].2H(2)O (4), (Et(3)NH)(2)[Cu(I)(2)(Hfcz)(2)(SiW(12)O(40))].H(2)O (5) and [Cu(I)(4)(Hfcz)(4)(SiMo(12)O(40))] (6). Their structures have been determined by single-crystal X-ray diffraction analyses, and the compounds are further characterized by elemental analyses, IR spectra and thermogravimetric (TG) analyses. In 1, Cu(II) cations are bridged by fluconazole ligands to form a 3D lvt coordination polymeric network, which is connected by (SiW(12)O(40))(4-) anions to form a complicated 3D (4,6)-connected framework with the topology of (4(2).6(4))(4(6).6(7).8(2))(2). In 2, two fcz(-) anions chelate two Cu(2+) cations to form a [Cu(fcz)](2)(2+) dimer, which is bridged by (SiW(12)O(40))(4-) polyanions to generate a 2D (4,4) grid. Compound 3 is formed by three types of co-crystallizing subunits including a dimer [Cu(fcz)](2)(2+), a dumbbell molecule [Cu(4)(fcz)(4)(SiW(12)O(40))] and an infinite chain {[Cu(2)(fcz)(2)(H(2)O)(2)(SiW(12)O(40))](2-)}(infinity). In compounds 4 and 5, Hfcz ligands link Cu(+) cations to generate 1D coordination polymeric units, and (SiW(12)O(40))(4-) polyanions connect these metal-organic units to form two types of (6(3)) sheets which are topological isomerism. In compound 6, (SiMo(12)O(40))(4-) polyanions fixed in Cu(I)-Hfcz square rings are further extended into a 2D sheet via linking Cu(I) atoms of different rings. By carefully inspection of the structures of 1-6, it is believed that various transition-metal organic units and Keggin polyanions with different coordination modes are important for the formation of the different structures. In addition, electrochemical behaviors of compounds 1, 2, 5 and 6 have been investigated.     

A feasible route to approach 3D POM-based hybrids: utilizing substituted or reduced Keggin anions with high charge density

Five new hybrid compounds based on Keggin polyanions, Ag(+)/Cu(+) ions and 1,3-bis(1,2,4-triazol-1-yl)propane (btp) molecules have been hydrothermally synthesized. In [Ag(5)(btp)(4)(H(2)O)(2)][PCuW(11)O(39)]·2H(2)O (1), [Ag(4.33)Na(0.67)(btp)(4)(H(2)O)(2)][PMnMo(11)O(39)]·H(2)O (2) and [Cu(4)(btp)(4)Na(H(2)O)(2)][PMnMo(11)O(39)]·2H(2)O (3), the neighboring mono-substituted Keggin clusters are alternately connected via sharing oxygen atoms to form an unusual Keggin-based transition-metal monosubstituted chain, in which the Keggin cluster serves as a decadentate ligand and grafts ten metal atoms representing the highest connected number for Keggin cluster and forming a 3D framework. In [Ag(5)(btp)(4)][PW(VI)(10)W(V)(2)O(40)] (4) and [Ag(5)(btp)(4)][PMo(VI)(10)Mo(V)(2)O(40)] (5), two-electron reduced Keggin clusters as hexadentate linkages are inserted in the rhomboid-like tunnels of the Ag-btp framework and connect with the framework via six Ag-O bonds to achieve 3D motifs, which are new and rare examples of heteropoly blue based hybrid compounds. The successful synthesis of the five high-dimensional structures may provide a feasible route for us to approach 3D polyoxometalate-based hybrids by using substituted Keggin anions and heteropoly blues with high charge density. Furthermore, photocatalytic experiments indicate that both 1 and 4 have good activities for photocatalytic degradation of RhB under UV irradiation. The luminescent properties of compounds 1-5 in the solid state were also investigated.     

Two hybrid polyoxometalate-pillared metal-organic frameworks

Two polyoxometalate-pillared 3D compounds, {Cu(5)(2-ptz)(6)(H(2)O)(4)(SiW(12)O(40))}·4H(2)O 1 and {Cu(9)(2-ptz)(12)(H(2)O)(6)(PMo(12)O(40))(2)}·H(2)O 2 (2-ptz = 5-(2-pyridyl)tetrazole) have been constructed based on different polyoxometalate anions, and copper-organic coordination polymer sheets by a hydrothermal method. Magnetic investigations reveal that both 1 and 2 exhibit antiferromagnetic coupling between the Cu(II) ions. Structural studies show the compound 1 exhibits a typical pcu-type net with the Sch?lfli symbol of {4(12)·6(3)}, and that compound 2 is a (3,4,6)-connected framework with novel {4(4)·6(10)·10}{6(3)}(2){6(5)·8} topology which has not been reported to date.     

Novel inorganic-organic hybrids constructed from multinuclear copper cluster and Keggin polyanions: from 1D wave-like chain to 2D network

Two novel inorganic-organic hybrids constructed from Keggin-type polyanions and multinuclear copper clusters based on 1-H-1,2,3-benzotriazole (HBTA), [Cu(I)(8)(BTA)(4)(HBTA)(8)(SiMo(12)O(40))]·2H(2)O (1) and [Cu(II)(6)(OH)(4)(BTA)(4)(SiW(12)O(40))(H(2)O)(6)]·6H(2)O (2), have been hydrothermally synthesized and structurally characterized by single crystal X-ray diffraction, elemental analyses, IR spectra and thermogravimetric (TG) analyses. In compound 1, eight Cu(I) ions were linked by twelve HBTA/BTA ligands to form an octanuclear Cu(I) cluster, which is connected by SiMo(12)O(40)(4-) anion with two bridging O atoms and two terminal O atoms to construct a one-dimensional (1D) wave-like chain. The octanuclear copper unit represents the maximum subunit linked just by amine ligands in the POMs system. In 2, four BTA ligands linked five Cu(II) ions constructing a pentanuclear "porphyrin-like" subunit, which is connected by another Cu(II) ion to form a 1D metal-organic band. The SiW(12)O(40)(4-) polyanions as tetradentate inorganic linkages extend the 1D band into a two-dimensional (2D) network with (8(3))(2)(8(5)·10) topology. To the best of our knowledge, compounds 1 and 2 represent the first examples of inorganic-organic hybrids based on metal-HBTA multinuclear subunits and polyoxometalates. The photocatalysis and electrochemical properties have been investigated in this paper.     

Synthesis, characterization, and photoresponsive properties of a series of Mo(IV)-Cu(II) complexes

Six Mo(IV)-Cu(II) complexes, [Cu(tpa)](2)[Mo(CN)(8)]·15H(2)O (1, tpa = tris(2-pyridylmethyl)amine), [Cu(tren)](2)[Mo(CN)(8)]·5.25H(2)O (2, tren = tris(2-aminoethyl)amine), [Cu(en)(2)][Cu(0.5)(en)][Cu(0.5)(en)(H(2)O)][Mo(CN)(8)]·4H(2)O (3, en = ethylenediamine), [Cu(bapa)](3)[Mo(CN)(8)](1.5)·12.5H(2)O (4, bapa = bis(3-aminopropyl)amine), [Cu(bapen)](2)[Mo(CN)(8)]·4H(2)O (5, bapen = N,N'-bis(3-aminopropyl)ethylenediamine), and [Cu(pn)(2)][Cu(pn)][Mo(CN)(8)]·3.5H(2)O (6, pn = 1,3-diaminopropane), were synthesized and characterized. Single-crystal X-ray diffraction analyses show that 1-6 have different structures varying from trinuclear clusters (1-2), a one-dimensional belt (3), two-dimensional grids (4-5), to a three-dimensional structure (6). Magnetic and ESR measurements suggest that 1-6 exhibit thermally reversible photoresponsive properties on UV light irradiation through a Mo(IV)-to-Cu(II) charge transfer mechanism. A trinuclear compound [Cu(II)(tpa)](2)[Mo(V)(CN)(8)](ClO(4)) (7) was synthesized as a model of the photoinduced intermediate.     

Polyoxometalates–Directed Assembly of Inorganic–Organic Hybrid Compounds with Copper Multinuclear Nano-cluster Based on Flexible Double Tetrazole-based Thioether

Two new inorganic–organic hybrid compounds constructed from different polyoxometalates (POMs) and copper multinuclear clusters, [Cu(bmte)(H₂Mo₈O₂₆)_0.5]·3H₂O (1) and [Cu₃(bmte)₃(HSiMo₁₂O₄₀)]·H₂O (2) (bmte = 1,2-bis(1-methyl-5-mercapto-1,2,3,4-tetrazole)ethane), have been synthesized under hydrothermal conditions with a flexible double tetrazole-based thioether and characterized by IR, TG and single-crystal X-ray diffraction analyses. In compound 1, two bmte ligands chelate two Cu^I ions with three N atoms to form a binuclear nano-scale subunit [Cu₂(bmte)₂]²⁺, then the binuclear Cu^I subunits are connected by [Mo₈O₂₆]⁴⁻ anions to build a one dimensional (1D) chain. In compound 2, a trinuclear nano-scale subunit [Cu₃(bmte)₃]³⁺ constructed from three Cu^I ions and three bmte ligands has been obtained, and the adjacent trinuclear subunits are linked by [SiMo₁₂O₄₀]⁴⁻ anions to form a “zipper” 1D chain. The adjacent chains of the title compounds are ultimately extended into 2D layers by hydrogen bonds between bmte and POMs. The structural difference of the two compounds indicates that the POMs play an important structure-directed role on the final networks. In addition, the electrochemical behavior of 2-modified carbon paste electrode (2-CPE) and its electrocatalytic reduction of nitrite have been discussed.     

Coulombic aggregations of Mn(III) salen-type complexes and Keggin-type polyoxometalates: isolation of Mn2 single-molecule magnets

The reaction of Mn(III) salen-type complexes with di- and tetraanionic α-Keggin-type polyoxometalates (POMs) was performed, and three types of Coulombic aggregations containing Mn(III) out-of-plane dimeric units (abbreviated as [Mn(2)](2+)) that are potentially single-molecule magnets (SMMs) with an S(T) = 4 ground state were synthesized: [Mn(2)(5-MeOsaltmen)(2)(acetone)(2)][SW(12)O(40)] (1), [Mn(2)(salen)(2)(H(2)O)(2)](2)[SiW(12)O(40)] (2), and [Mn(5-Brsaltmen)(H(2)O)(acetone)](2)[{Mn(2)(5-Brsaltmen)(2)}(SiW(12)O(40))] (3), where 5-Rsaltmen(2-) = N,N'-(1,1,2,2-tetramethylethylene)bis(5-R-salicylideneiminate) with R = MeO (methoxy), Br (bromo) and salen(2-) = N,N'-ethylenebis(salicylideneiminate). Compound 1 with a dianionic POM, [SW(12)O(40)](2-), is composed of a 1:1 aggregating set of [Mn(2)](2+)/POM, and 2, with a tetraanionic POM, [SiW(12)O(40)](4-), is a 2:1 set. Compound 3 with [SiW(12)O(40)](4-) forms a unique 1D coordinating chain with a [-{Mn(2)}-POM-](2-) repeating unit, for which a hydrogen-bonded dimeric unit ([Mn(5-Brsaltmen)(H(2)O)(acetone)](2)(2+)) is present as a countercation. Independent of the formula ratio of [Mn(2)](2+)/POM, Mn(III) dimers and POM units in 1-3 form respective segregated columns along a direction of the unit cell, which make an alternate packing to separate evenly identical species in a crystal. The nearest intermolecular Mn···Mn distance is found in the order 2 < 3 < 1. The segregation of the [Mn(2)](2+) dimer resulted in interdimer distances long enough to effectively reduce the intermolecular magnetic interaction, in particular in 1 and 3. Consequently, an intrinsic property, SMM behavior, of Mn(III) dimers has been characterized in this system, even though the interdimer interactions are still crucial in the case of 2, where a long-range magnetic order competitively affects slow relaxation of the magnetization at low ac frequencies.     

Self-assembly of unprecedented [8+12] Cu-metallamacrocycle-based 3D metal-organic frameworks

[8+12]-metallamacrocycle-based 3D frameworks {[Cu(4)(pbt)(2)(SO(4))(2)(DMF)(2)(CH(3)OH)]·7H(2)O·DMF}(n) (1) and [12]-macrocycle 3D {[Cu(2)(pbt)(SO(4))(DMSO)(CH(3)OH)(2)]·5H(2)O·CH(3)OH}(n) (2) have been obtained. Both complexes display antiferromagnetic couplings and high catalytic activity in the oxidative coupling reaction of 1-ethynylbenzene and oxazolidin-2-one.     

Polyoxometalate-templated lanthanide-organic hybrid layers based on 6(3)-honeycomb-like 2D nets

The reaction of a double-betaine-containing ligand with LnPMo(12)O(40)·nH(2)O (Ln = Dy, Tb and Er) led to the isolation of new polyoxometalate-templated lanthanide-organic hybrid layers with the molecular formula [Ln(L)(1.5)(H(2)O)(5)][PMo(12)O(40)]·1.5CH(3)CN·2H(2)O (Ln = Dy (1), Tb (2) and Er (3); L = 1,4-bis(pyridinil-4-carboxylato)-l,4-dimethylbenzene). All compounds were characterized by elemental analyses, TG analyses, IR and the single-crystal X-ray diffraction. Compounds 1-3 are isostructural and possess a 2D undulating cationic network [Ln(L)(1.5)(H(2)O)(5)](n)(3n+) with the honeycomb-like cavities. Interestingly, the interval 2D networks are further connected by the H-bonds to form a 3D supramolecular framework. Moreover, two of such identical supramolecular frameworks are 2-fold interpenetrated with each other and encapsulate the α-Keggin-type [PMo(12)O(40)](3-) anionic templates and the solvent molecules. These composite compounds display both luminescent properties (induced by organic ligands and/or lanthanide ions) and electrocatalytic activities towards the reduction of nitrite.     

Construction of polyoxometalates-based coordination polymers through direct incorporation between polyoxometalates and the voids in a 2D network

A series of polyoxometalates (POMs)-based coordination polymers, namely, {[Cu(2,3-Me2pz)(2,5-Me2pz)0.5]4(SiW12O40)(2,5-Me2pz)}n (2,3-Me2pz = 2,3-dimethylpyrazine; 2,5-Me2pz = 2,5-dimethylpyrazine; 1), {[Cu2(4,4'-bipy)4(H2O)4](SiW12O40)(H2O)18}n (4,4'-bipy = 4,4'-bipyridine; 2), {[Cu(2-Mepz)1.5]3(PMo12O40)(H2O)3.5}n (2-Mepz = 2-methylpyrazine; 3), {[Ag(2,3-Me2pz)1.5]4(SiW12O40}n (4), {[Cu(pz)1.5]4(SiW12O40)(H2O)3}n (pz = pyrazine; 5), {[Cu(2,3-Me2pz)1.5]4(SiW12O40)}n (6), {[Cu(4,4'-bipy)1.75]4(SiW12O40)(H2O)2}n (7), and {[Cu2(4,4'-bipy)4(H2O)4](SiW12O40)(4,4'-bipy)2(H2O)4}n (8), were synthesized through direct incorporation between POMs and the voids of the 2D network. Crystal structural analysis reveals that the relationship between the size of the void of the 2D network and that of POMs is of key importance for successful synthesis of POMs-based open metal-organic frameworks. Guest replacement shows that the pore size of the framework constructed through direct incorporation between POMs and the voids of the 2D network is very sensitive to guest molecules.     

Hexameric polyoxometalates decorated by six 3d-4f heterometallic clusters

Two nanosized hexameric polyoxometalate-based solid state assemblies (H(2)en)(6)Na(15)K(9)[Dy(6)Fe(6)(H(2)O)(12)(SiW(10)O(38))(6)]·34H(2)O (1) and K(13)Na(17)[H(2)en](3)[Tb(6)Fe(6)(H(2)O)(12)(SiW(10)O(38))(6)]·40H(2)O (2) (en = 1,2-ethylenediamine), decorated by six [Ln-(μ(3)-O)(3)-Fe] 3d-4f heterometallic clusters, have been synthesized by the hydrothermal method, and characterized by IR, element analysis, magnetic studies and the single-crystal X-ray analyses. The detailed study of the synthetic conditions reveals that the use of the organic ligands, pH value and the reaction temperature all play important roles in the synthesis of the 3d-4f heterometallic POMs. Magnetic study suggests the presence of antiferromagnetic interactions in these two compounds.     

1,2,4-Triazole functionalized adamantanes: a new library of polydentate tectons for designing structures of coordination polymers

A series of functionalized adamantanes: 1,3-bis(1,2,4-triazol-4-yl)(tr(2)ad); 1,3,5-tris(1,2,4-triazol-4-yl)-(tr(3)ad); 1,3,5,7-tetrakis(1,2,4-triazol-4-yl)adamantanes (tr(4)ad) and 3,5,7-tris(1,2,4-triazol-4-yl)-1-azaadamantane (tr(3)ada) were developed as a new family of geometrically rigid polydentate tectons for supramolecular synthesis of framework solids. The coordination compounds were prepared under hydrothermal conditions; their structures reveal a special potential of the triazolyl adamantanes for the generation of highly-connected and open frameworks as well as structures based upon polynuclear metal clusters assembled with short-distance N(1),N(2)-triazole bridges. Complexes [Cd{L}(2)]A·nH(2)O [L = tr(3)ad, A = 2NO(3)(-) (4), CdCl(4)(2-) (5); L = tr(3)ada, A = CdI(4)(2-) (7)] are isomorphous and adopt a layered 3,6-connected structure of CdI(2) type. [{Cu(3)(OH)}(2)(SO(4))(5)(H(2)O)(2){tr(3)ad}(3)]·26H(2)O (6) is a layered polymer based upon Cu(3)(μ(3)-OH) nodes and trigonal tr(3)ad links. In [Cu(3)(OH)(2){tr(3)ada}(2)(H(2)O)(4)](ClO(4))(4) (8), [Cu(2){tr(3)ada}(2)(H(2)O)(3)](SO(4))(2)·7H(2)O (9) and [Cd(2){tr(3)ada}(3)]Cl(4)·28H(2)O (10) (UCl(3)-type net) the organic tripodal ligands bridge polynuclear metal clusters. Complexes [Ag{tr(4)ad}]NO(3)·3.5H(2)O (11) and [Cu{tr(4)ad}(H(2)O)](ClO(4))(2)·3H(2)O (12) have 3D SrAl(2)-type frameworks with the metal ions and adamantane tectons as topologically equivalent tetrahedral nodes, while in [Cd(3)Cl(6){tr(4)ad}(2)]·9H(2)O (13) the ligands bridge trinuclear six-connected Cd(3)Cl(6)(μ-tr)(4)(tr)(2) clusters. In the compounds [Cd(2){tr(2)ad}(4)(H(2)O)(4)](CdBr(4))(2)·2H(2)O (2) and [Cd{tr(2)ad}(4){CdI(3)}(2)]·4H(2)O (3) the bitopic ligands provide simple links between the metal ions, while in [Ag(2){tr(2)ad}(2)](NO(3))(2)·2H(2)O (1) the ligand is tetradentate and generates a 3D framework.     

Assembly and properties of transition-metal coordination polymers based on semi-rigid bis-pyridyl-bis-amide ligand: effect of polycarboxylates on the dimensionality

Seven new coordination polymers, [Co()(1,3-BDC)(H(2)O)(3)]·H(2)O (), [Co()(1,2-BDC)(H(2)O)]·H(2)O (), [Co(3)()(1,2,4-BTC)(2)(H(2)O)(4)]·4H(2)O (), [Co()(NPH)]·2H(2)O (), [Cu()(1,3-BDC)] (), [Cu()(1,2-BDC)] (), [Cu()(1,3,5-HBTC)(H(2)O)](2)·2H(2)O () ( = N,N'-bis(pyridin-3-yl)cyclohexane-1,4-dicarboxamide, 1,3-H(2)BDC = 1,3-benzenedicarboxylic acid, 1,2-H(2)BDC = 1,2-benzenedicarboxylic acid, 1,2,4-H(3)BTC = 1,2,4-benzenetricarboxylic acid, H(2)NPH = 3-nitrophthalic acid and 1,3,5-H(3)BTC = 1,3,5-benzenetricarboxylic acid) have been hydrothermally synthesized by assembling transition-metal cobalt-copper salts with semi-rigid bis-pyridyl-bis-amide ligand and different aromatic polycarboxylic acids. Complex exhibits a one-dimensional (1D) sinusoidal-like chain, which is further assembled into a three-dimensional (3D) supramolecular framework through hydrogen-bonding interactions. Complex possesses a 3D framework with 4-connected 6(6) topology, which contains a two-dimensional (2D) distorted asymmetric hexagonal grid. When 1,2,4-BTC is used in complex , a 3D framework with (6(3)·8(2)·10)(2)(6(5)·8)(2)(8) topology is constructed. Complex possesses a 3D framework with 4-connected 6(6) topology, which is similar to that of except for containing a 2D symmetric hexagonal grid. When Co(II) ion is replaced by Cu(II) ion, the 3D framework of complex with (4·6(2))(4·6(6)·8(3)) topology based on and 1,3-BDC ligands is obtained. Complex shows a 2D cross network consisting of a superposed Cu- 1D chain and 1,2-BDC, which is further expanded into a 3D supramolecular framework by hydrogen-bonding interactions. In complex , 1,3,5-HBTC is employed as the auxiliary ligand, and a 3D supramolecular framework based on the undulated 2D layers is formed through π-π stacking and hydrogen-bonding interactions. Both the metal ions and polycarboxylates play important roles in the construction of the title complexes. In addition, the electrochemical behaviors and the fluorescence properties of the seven complexes have been investigated.     

Two three-dimensional {V16Ge4}-based open frameworks stabilized by diverse types of Co(II)-amine bridges and magnetic properties

Two novel three-dimensional (3D) extended vanadogermanate-based frameworks, [Co(pdn)(2)](3)[Co(2)(pdn)(4)][V(16)Ge(4)O(44)(OH)(2)(H(2)O)]·5H(2)O (1), [Co(2)(en)(3)][Co(en)(2)](2)[Co(en)(2)(H(2)O)][V(16)Ge(4)O(44)(OH)(2)(H(2)O)]·10.5H(2)O (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 [V(16)Ge(4)O(44)(OH)(2)(H(2)O)](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 {V(16)Ge(4)} clusters as nodes, while compound 2 exhibits a 3D (4,6)-connected network with a Schl?fli symbol of (4(6)·6(7)·8(2))(2)(4(2)·6(4)), 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.     

Distinct structures of coordination polymers incorporating flexible triazole-based ligand: topological diversities, crystal structures and property studies

Six new coordination polymers, namely {[Zn(btec)(0.5)(btmb)]·2H(2)O}(n) (1), {[Co(btec)(0.5)(btmb)(H(2)O)]·3H(2)O}(n) (2), {[Cu(btec)(0.5)(btmb)]·H(2)O}(n) (3), {[Cu(4)(btc)(4)(btmb)(4)]·H(2)O}(n) (4), {[Co(3)(bta)(2)(btmb)(2)]·2H(2)O}(n) (5), [Co(Hbta)(btmb)](n) (6) (H(4)btec = 1,2,4,5-benzenetetracarboxylate, H(3)btc = 1,3,5-benzenetricarboxylate, H(3)bta = 1,2,4-benzenetricarboxylate and btmb = 4,4'-bis(1,2,4-triazol-1-ylmethyl)biphenyl), have been successfully synthesized under hydrothermal conditions. All these complexes were structurally determined by single-crystal X-ray diffraction, elemental analysis, IR, TGA and XRD. Crystal structural analysis reveals that 1 is the first example of an unusual 3D framework with (8(6)) topology containing a 2D molecular fabric structure. Complex 2 exhibits a 3D NbO network with (6(4)·8(2)) topology. In 3, Cu(II) ions are coordinated by anti-conformational btmb ligands to form left- and right-handed double helices, which are further bridged by the 4-connected btec(4-) anions to give a 3D porous network. Complex 4 presents a rare 3D gra network structure with (6(3))(6(9)·8) topology. 5 and 6 were obtained through controllable pH values of solution, 5 features a scarce binodal (3,8)-connected tfz-d framework with the trinuclear Co(II) clusters acting as nodes, whereas 6 has an extended 2D 4(4) grid-like layer and the adjacent 2D layers are interconnected by strong hydrogen bonding interactions into a 3D supramolecular framework. The structural diversities indicate that distinct organic acid ligands, the nature of metal ions and the pH value play crucial roles in modulating the formation of the resulting coordination complexes and the connectivity of the ultimate topological nets. Moreover, magnetic susceptibility measurement of 5 indicates the presence of weak ferromagnetic interactions between the Co(II) ions bridged by carboxylate groups.     

Diverse structures and adsorption properties of quasi-Werner-type copper(II) complexes with flexible and polar axial bonds

The quasi-Werner-type copper(II) complex, [Cu(PF(6))(2)(4-mepy)(4)] (1), in which 4-mepy is the 4-methylpyridine ligand, has flexible and polar axial bonds of Cu-PF(6). Flexibility of the Cu-PF(6) bonds induces diverse and unprecedented guest-inclusion structures, such as {[Cu(PF(6))(2)(4-mepy)(4)][Cu(PF(6))(4-mepy)(4)(acetone)]·PF(6)·4acetone} (γ-1?2.5acetone), {[Cu(PF(6))(2)(4-mepy)(4)][Cu(PF(6))(4-mepy)(4)(2-butanone)]·PF(6)·3.5(2-butanone)} (γ-1?2.25(2-butanone)), {[Cu(PF(6))(2)(4-mepy)(4)][Cu(PF(6))(4-mepy)(4)(H(2)O)]·PF(6)·4benzene} (γ-1?0.5H(2)O·2benzene), and {[Cu(PF(6))(2)(4-mepy)(4)]·2benzene} (γ-1?2benzene). Exposure of the dense form, α-1, to benzene vapor affords the benzene-inclusion complex {[Cu(PF(6))(2)(4-mepy)(4)]·2benzene} (γ-1?2benzene), all benzene guests of which are easily removed by vacuum drying, reforming guest-free, dense α-1' with smaller sized crystals than α-1. In contrast to α-1, which shows almost no CO(2) adsorption, α-1' adsorbs CO(2) gas with structural transformations, this being the first example that exhibits adsorption of gas in a dense Werner-type complex and a drastic change in adsorption properties depending on the size of the crystals.     

Four di-Cu(II)-substituted sandwich-type germanomolybdates obtained under different reaction conditions: from zero-dimensional to two-dimensional structure

Four di-Cu(II)-substituted sandwich-type germanomolybdates, (H(2)en)(2)H(7){[Na(0.5)(H(2)O)(3.5)](2)[Cu(2)(β-Y-GeMo(9)O(33))(2)]}·6H(2)O (1), (H(2)en)(2)H{[Na(2.5)(H(2)O)(12)](2)[Cu(en)(2)][Cu(2)(β-Y-GeMo(9)O(33))(2)]}·8H(2)O (2), [Na(4)(H(2)O)(12)](2)H(4)[Cu(2)(β-Y-GeMo(9)O(33))(2)]}·11H(2)O (3) and [Cu(en)(2)](2)[Cu(en)(2)(H(2)O)](2){[Cu(en)(2)](2)[Cu(2)(β-Y-GeMo(9)O(33))(2)]}·8H(2)O (4) (en = ethylenediamine), have been prepared. It is interesting that 1-3 were obtained in the same aqueous solution reaction system but exhibited different structures: 1 displays a 0D structure, 2 shows an organic-inorganic 1D chain structure, while 3 displays a 2D network. 4 was synthesized under hydrothermal condition by the same reagents, which represents the first transition metal-sandwiched organic-inorganic 2D heteropolymolybdate.     

Cobalt(II), nickel(II), copper(II), and zinc(II) complexes with [3(5)]adamanzane, 1,5,9,13-tetraazabicyclo[7.7.3]nonadecane, and [(2.3)(2).2(1)] adamanzane, 1,5,9,12-tetraazabicyclo[7.5.2]hexadecane

Isolation of the free bicyclic tetraamine, [3(5)]adamanzane.H(2)O (1,5,9,13-tetraazabicyclo[7.7.3]nonadecane.H(2)O), is reported along with the synthesis and characterization of a copper(II) complex of the smaller macrocycle [(2.3)(2).2(1)]adamanzane (1,5,9,12-tetraazabicyclo[7.5.2]hexadecane) and of three cobalt(II), four nickel(II), one copper(II), and two zinc(II) complexes with [3(5)]adamanzane. For nine of these compounds (2-8, 10b, and 12) the single-crystal X-ray structures were determined. The coordination geometry around the metal ion is square pyramidal in [Cu([(2.3)(2).2(1)]adz)Br]ClO(4) (2) and trigonal bipyramidal in the isostructural structures [Cu([3(5)]adz)Br]Br (3), [Ni([3(5)]adz)Cl]Cl (5), [Ni([3(5)]adz)Br]Br (6), and [Co([3(5)]adz)Cl]Cl (8). In [Ni([3(5)]adz)(NO(3))]NO(3) (4) and [Ni([3(5)]adz)(ClO(4))]ClO(4) (7) the coordination geometry around nickel(II) is a distorted octahedron with the inorganic ligands at cis positions. The coordination polyhedron around the metal ion in [Co([3(5)]adz)][ZnCl(4)] (10b) and [Zn([3(5)]adz)][ZnCl(4)] (12) is a slightly distorted tetrahedron. Anation equilibrium constants were determined spectrophotometrically for complexes 2-6 at 25 and 40 degrees C and fall in the region 2-10 M(-1) for the halide complexes and 30-65 M(-1) for the nickel(II) nitrate complex (4). Rate constants for the dissociation of the macrocyclic ligand from the metal ions in 5 M HCl were determined for complexes 2, 3, 5, 8, 10, and 12. The reaction rates vary from half-lives at 40 degrees C of 14 min for the dissociation of the Zn([3(5)]adz)(2+) complex (12) to 14-15 months for the Ni([3(5)]adz)Cl(+) ion (5).     

Highly porous 4,8-connected metal-organic frameworks: synthesis, characterization, and hydrogen uptake

A series of highly porous 4,8-connected isoreticular MOFs of the scu topology [Cu(4)(L(1))(H(2)O)(4)]·20DEF, [Cu(4)(L(2))(H(2)O)(4)]·16DMF·5H(2)O, and [Cu(4)(L(3))(H(2)O)(4)]·14DMF (L(1)-L(3) are (R)-1,1'-binaphthyl-derived octacarboxylate bridging ligands) were synthesized and characterized by single-crystal X-ray crystallography. Although the frameworks exhibit some distortion during the solvent removal process, the high-connectivity nature of the building blocks helps in stabilizing the frameworks, leading to high surface areas (S(BET) = 1189-2448 m(2)/g) and significant hydrogen uptake of up to 1.8 wt % (77 K, 1 atm).