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.     

Construction of different dimensional inorganic-organic hybrid materials based on polyoxometalates and metal-organic units via changing metal ions: from non-covalent interactions to covalent connections

Five POM-based hybrid materials have been designed and synthesized based on different metal ions under hydrothermal conditions, namely, [Zn(Hfcz)(H(2)O)(3)](H(3)fcz)(SiMo(12)O(40)).3H(2)O (1), [Cd(2)(Hfcz)(6)(H(2)O)(2)](SiMo(12)O(40)).H(2)O (2), [Co(2)(Hfcz)(2)(SiW(12)O(40))](H(3)fcz)(2)(SiW(12)O(40)).10H(2)O (3), [Ni(2)(Hfcz)(4)(H(2)O)(2)](SiW(12)O(40)).5H(2)O (4) and [Ag(4)(Hfcz)(2)(SiMo(12)O(40))] (5), where Hfcz is fluconazole [2-(2,4-difluorophenyl)-1,3-di(1H-1,2,4-triazol-1-yl)propan-2-ol]. Their crystal structures have been determined by X-ray diffraction, elemental analyses, IR spectra, and thermogravimetric analyses (TGA). There are 1D mono and double chain-like metal-organic units in compounds 1 and 2, respectively. Polyoxometalates and metal-organic units co-crystallize through hydrogen bonds. In compound 3, metal-organic sheets are pillared by one kind of polyanion through covalent connections to generate a sandwich double-sheet. The other kind of polyanion acts as a counter-ion and lies in two adjacent sandwich double-sheets through non-covalent interactions. Polyanions covalently link metal-organic sheets to extend to an unusual 3D 5-connected framework with the (4(4).6(6)) topology in 4. In compound 5, polyanions link metal-organic chains to form a sheet through covalent connections. It is interesting that compound 5 shows an intricate (4,5,10)-connected framework with (4(4).6(2))(4)(4(8).6(2))(2)(4(14).6(19).8(12)) topology based on two kinds of Ag cations as four-connected and five-connected nodes, and polyanions as ten-connected nodes, when AgO interactions are considered. It represents the highest connected network topology presently known for polyoxometalate systems. The structural differences among 1-5 indicate the importance of different metal-organic units, coordination modes of polyanions for framework formation, and the interactions between polyanions and metal-organic units. In addition, the luminescent properties of compounds 1, 2 and 5, and electrochemical behaviours of compounds 1-5 have been investigated.     

Zeolite ionic crystals assembled through direct incorporation of polyoxometalate clusters within 3D metal-organic frameworks

Polyoxometalate-based metal-organic frameworks {[Gd(dpdo)(4)(H(2)O)(3)](PMo(12)O(40))(H(2)O)(2)CH(3)CN}(n) (2), {[Dy(dpdo)(4)(H(2)O)(3)](PMo(12)O(40))(H(2)O)(20CH(3)CN}(n) (3), {[Gd(dpdo)(4)(H(2)O)(3)](H(3)O)(SiMo(12)O(40))(dpdo)(0.5)(CH(3)CN)(0.5) (H(2)O)(3)}(n) (4), {[Ho(dpdo)(4)(H(2)O)(3)](H(3)O)(SiMo(12)O(40))(dpdo)(0.5)(CH(3)CN)(0.5)(H(2)O)(3)}(n) (5), {[Ni(dpdo)(2)(CH(3)CN) (H(2)O)(2)](2)(SiMo(12)O(40))(H(2)O)(2)}(n) (6), and {[Ni(dpdo)(3)](4)(PW(12)O(40))(3)[H(H(2)O)(27)(CH(3)CN)(12)]}(n) (7) (where dpdo is 4,4'-bipyridine-N,N'-dioxide) were constructed via self-assembly by embedding Keggin-type polyanions within the intercrystalline voids as guests or pillars. Compounds 2 and 3 are isomorphic and exhibit three-dimensional (3D) noninterwoven 64 frameworks with distorted-honeycomb cavities occupied by the polyanions. Compounds 4 and 5 are comprised of 3D noninterwoven frameworks formed by linking the adjacent folded sheets through hydrogen bonds and pi-pi stacking interactions relative to the free isolated dpdo ligand. Compound 6 is a pillar-layered framework with the [SiMo(12)O(40)](4-) anions located on the square voids of the two-dimensional bilayer sheets formed by the dpdo ligands and nickel(II) ions. Compound 7 is a 3D metal-organic framework formed by nickel(II) and 4,4'-bipyridine-N,N'-dioxide with the globular Keggin-structure [PW(12)O(4)](3-) anion as the template. A large protonated water cluster H(+)(H(2)O)(27) is trapped and stabilized within the well-modulated cavity.     

Application of tetrazole-functionalized thioethers with different spacer lengths in the self-assembly of polyoxometalate-based hybrid compounds

Three metal-organic networks based on Keggin-type polyoxometalates (POMs) have been hydrothermally synthesized by tuning the spacer lengths of bis(tetrazole)-functionalized thioether ligands and structurally characterized: [Cu(4)(bmtm)(4)][SiW(12)O(40)]·2H(2)O (1), [Cu(4)(bmte)(3.5)][SiW(12)O(40)] (2), and [Cu(4)(bmtp)(4)][SiW(12)O(40)] (3) [bmtm = 1,1'-bis(1-methyl-5-mercapto-1,2,3,4-tetrazole)methane, bmte = 1,2-bis(1-methyl-5-mercapto-1,2,3,4-tetrazole)ethane, and bmtp = 1,5-bis(1-methyl-5-mercapto-1,2,3,4-tetrazole)pentane]. The spacer lengths and sulfhydryl of bis(tetrazole)-functionalized thioether ligands play important roles in the final framework formation, as shown by X-ray diffraction analysis. In compound 1, with the connection of a N,S bridge of bmtm, two kinds of binuclear Cu(I) units are formed and linked to construct a one-dimensional (1D) chain. The [SiW(12)O(40)](4-) (SiW(12)) cluster provides four terminal O atoms linking four binuclear units to generate a two-dimensional layer with (8(3))(2)(8(5)·10) topology. In compound 2, centrosymmetric octameric moieties composed of two equivalent tetrameric Cu(I) units are bridged by bmte ligands to form a 1D chain. The SiW(12) clusters show an unusual (2,8)-connected mode to connect with the 1D chain and construct a four-connected three-dimensional (3D) network with 5(3)·6(2)·7 topology. Compound 3 exhibits a rare 3D host framework with a type of large cavity and two types of small windows. The SiW(12) clusters as templates are strongly cemented into the large cavities and completely encircled by small windows. Furthermore, the compound 2 bulk-modified carbon-paste electrode (2-CPE) displays good electrocatalytic activity toward the reduction of nitrite.     

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.     

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.     

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.     

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.     

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.     

Inorganic-organic hybrid compounds based on octamolybdates and metal-organic fragments with flexible multidentate ligand: syntheses, structures and characterization

Six polyoxometalate-based (POM) hybrid materials based on octamolybdate building blocks and metal-organic fragments with flexible multidentate ligand, namely [Cu(II)(2)(ttb)(2)(β-Mo(8)O(26))(H(2)O)(2)]·2H(2)O (1), Cu(I)(4)(ttb)(2)(β-Mo(8)O(26))(H(2)O) (2), [Cu(I)(4)(ttb)(3)(β-Mo(8)O(26))] (3), [Ni(2)(ttb)(2)(β-Mo(8)O(26))(H(2)O)(6)]·2H(2)O (4), [Zn(2)(ttb)(2)(α-Mo(8)O(26))(H(2)O)(2)] (5), and [Ag(4)(ttb)(2)(β-Mo(8)O(26))] (6), where ttb = 1,3,5-tris(1,2,4-triazol-1-ylmethyl)-2,4,6-trimethyl benzene, have been synthesized under hydrothermal conditions. Their structures have been determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses, TGA, IR spectra, and electrochemistry. Compounds 1 and 2 exhibit three-dimensional (3D) 2-fold interpenetrating frameworks with (3,6)-connected (4(1)·6(2))(4(2)·6(10)·10(3)) and (3,4)-connected (6(2)·8(1))(2)(6(2)·8(4)) topologies, respectively. We are not aware of any other examples of interpenetrating (3,6)- and (3,4)-connected frameworks which involves the octamolybdates. Compound 3 shows a rare two-dimensional (2D) 2-fold interpenetrating network structure. In compound 4, a 3D supramolecular framework with the channels is constructed by the hydrogen-bonding interactions between (β-Mo(8)O(26))(4-) polyanions and the Ni-ttb double layers, in which the guest (β-Mo(8)O(26))(4-) anions are included. If ZnO interactions are considered, the structure of 5 is a 3D (3,4)-connected framework with (4·8(2))(4·8(2)·10(3)) topology. In 6, the ttb ligand as a tetradentate ligand links the Ag atoms to yield a 2D POM-based network. By careful inspection of the structures of 1-6, it can be seen that the ttb ligand, the metal ion and the coordination mode of the octamolybdate anion play important roles in the formation of the POM-based MOFs.     

Step-wise synthesis of inorganic-organic hybrid based on γ-octamolybdate-based tectons

With the bottom-up design principle, we use metal-ions to bridge the predesigned tectons (1 [(H(2)L(1))(2)(Mo(8)O(26))]·4H(2)O and 3 [(H(2)L(2))(L(2))(0.5)(Mo(8)O(26))(0.5)]·H(2)O) so that two higher dimensional γ-octamolybdate based inorganic-organic hybrid compounds 2 [Cu(I)(2)(L(1))(3)(Mo(8)O(26))(0.5)] and 4 [Ni(L(2))(2)(HL(2))(2)(Mo(8)O(26))]·4H(2)O are successfully obtained.     

Polymeric networks of copper(II) using succinate and aromatic N-N donor ligands: synthesis, crystal structure, magnetic behaviour and the effect of weak interactions on their crystal packing

Four succinato-bridged complexes of copper(II) have been synthesized. Complex 1, [Cu(2)(mu-OH(2))(2)L(bpy)(2)(NO(3))(2)](n) and 2, [Cu(2)(mu-OH(2))(2)L(phen)(2)(NO(3))(2)](n)(bpy = 2,2[prime or minute]-bipyridine; phen = 1,10-phenanthroline and LH(2)= succinic acid) exhibit 1D coordination polymer structures where both the nitrate ions are directly linked to the copper(ii) producing synthons in a 2D sheet. A novel 2D grid-like network, ([Cu(4)L(2)(bpy)(4)(H(2)O)(2)](ClO(4))(4)(H(2)O))n3, is obtained upon changing the nitrate by perchlorate anion in complex 1, where the channels are occupied by the anions. On changing the nitrate by tetrafluoroborate anion in complex 2, a novel octanuclear complex, [Cu(8)L(4)(phen)(12)](BF(4))(8).8H(2)O 4, is isolated. The coligand bpy and phen in these complexes show face-to-face (in 1,2,3,4) or edge-to-face (in 4 )pi-pi interactions forming the multidimensional supramolecular architectures. Interestingly, the appearance of edge-to-face pi-pi interactions in complex facilitates the formation of discrete octanuclear entities. Variable-temperature (300-2 K) magnetic measurements of complexes have been done. Complexes 1 and 2 show very weak antiferromagnetic (OOC-CH(2)-CH(2)-COO) and ferromagnetic coupling (mu-H(2)O). Complex 3 also shows antiferromagnetic (syn-syn mu-OCO), and ferromagnetic coupling (mu-O of the -COO group). Complex 4 with two types (syn-syn and syn-anti) of binding modes of the carboxylate group shows strong antiferromagnetic interaction.     

A three-dimensional ferromagnet based on linked copper-azido clusters

Two novel three-dimensional coordination polymers [Cu(6)(N(3))(12)(N-Eten)(2)](n) (1) (N-Eten=N-ethylethylenediamine) and {[Cu(9)(N(3))(18)(1,2-pn)(4)].H(2)O}(n) (2) (1,2-pn=1,2-diaminopropane) have been synthesized by the self-assembly reactions of Cu(NO(3))(2).3H(2)O, NaN(3) and small diamine ligands. Their molecular structures were determined by single-crystal X-ray diffraction. Complex 1 is composed of a neutral 3D coordination framework based on unprecedented hexanuclear copper(ii) clusters which features three types of bridging modes for azide (mu-1,1, mu-1,3 and mu-1,1,3). Complex 2 is a novel 3D coordination polymer featuring octanuclear copper-azido clusters and [Cu(diamine)(2)](2+) units which are linked by azido bridges. Magnetic studies for complex show ferromagnetic ordering at 3.5 K, where the azido bridges mediate ferromagnetic coupling between adjacent Cu(II) ions. The magnetic data for 1 were fitted to a uniform hexanuclear copper model which yielded g=2.21, J=6.26 cm(-1), zJ'=0.39 cm(-1). Complex 2 shows ferromagnetic coupling in the octanuclear unit and antiferromagnetic interaction between neighboring units.     

Structural evolution and magnetic properties of Co(II) coordination polymers varied from 1D to 3D constructed by 1,4-bis(1,2,4-triazol-1-ylmethyl)benzene

Seven Co(II) coordination polymers, [Co(btx)(3)(H(2)O)(2)](ClO(4))(2)·(btx)·2H(2)O (1), [Co(btx)(3)(H(2)O)(2)](BF(4))(2)·(btx)·2H(2)O (2), [Co(btx)(2)(H(2)O)(2)](NO(3))(2)·2H(2)O (3), [Co(btx)(2)Cl(2)] (4), [Co(btx)(BA)(2)(H(2)O)(2)]·2HBA (5), [Co(btx)(IPA)] (6) and [Co(3)(btx)(3)(BTA)(2)(H(2)O)(2)] (7) (btx = (1,4-bis(1,2,4-triazol-1-ylmethyl)benzene), HBA = benzoic acid, H(2)IPA = isophthalic acid, H(3)BTA = benzene-1,3,5-tricarboxylic acid), have been hydrothermally synthesized and characterized. 1 and 2 are isostructural and show a 1D Co-μ(2)-btx-Co chain structure, in which btx acts as both a bridging and terminal ligand. 3 is also a 1D chain structure but different from 1 and 2. The Co(II) ions are bridged by double μ(2)-btx to form Co(2)-btx(2) rings, which were further connected into 1D chains by sharing the Co(II) ions of the rings. 4 exists as a 2D grid with (4,4) topology structure. When aromatic acid was introduced to the synthetic system, three other coordination polymers 5-7 were obtained. In 5, the 1D chain is as that of 1, except that the terminal ligand was replaced by BA(-). 6 shows a two-fold parallel interpenetration framework featuring a 6-c uninodal net with (3(3),4(6),5(5),6) Schlafli topological symbol. 7 is an interesting 3D framework, which contains a 2-nodal net motif with the unprecedented (3(6),4(2),5(6),6)(3(9),4(9),5(3))(2) topology structure. The influence of the varieties of the structures and magnetic properties are studied and discussed in detail.     

Di- and tetra-nuclear copper(II), nickel(II), and cobalt(II) complexes of four bis-tetradentate triazole-based ligands: synthesis, structure, and magnetic properties

Four bis-tetradentate N(4)-substituted-3,5-{bis[bis-N-(2-pyridinemethyl)]aminomethyl}-4H-1,2,4-triazole ligands, L(Tz1)-L(Tz4), differing only in the triazole N(4) substituent R (where R is amino, pyrrolyl, phenyl, or 4-tertbutylphenyl, respectively) have been synthesized, characterized, and reacted with M(II)(BF(4))(2)·6H(2)O (M(II) = Cu, Ni or Co) and Co(SCN)(2). Experiments using all 16 possible combinations of metal salt and L(TzR) were carried out: 14 pure complexes were obtained, 11 of which are dinuclear, while the other three are tetranuclear. The dinuclear complexes include two copper(II) complexes, [Cu(II)(2)(L(Tz2))(H(2)O)(4)](BF(4))(4) (2), [Cu(II)(2)(L(Tz4))(BF(4))(2)](BF(4))(2) (4); two nickel(II) complexes, [Ni(II)(2)(L(Tz1))(H(2)O)(3)(CH(3)CN)](BF(4))(4)·0.5(CH(3)CN) (5) and [Ni(II)(2)(L(Tz4))(H(2)O)(4)](BF(4))(4)·H(2)O (8); and seven cobalt(II) complexes, [Co(II)(2)(L(Tz1))(μ-BF(4))](BF(4))(3)·H(2)O (9), [Co(II)(2)(L(Tz2))(μ-BF(4))](BF(4))(3)·2H(2)O (10), [Co(II)(2)(L(Tz3))(H(2)O)(2)](BF(4))(4) (11), [Co(II)(2)(L(Tz4))(μ-BF(4))](BF(4))(3)·3H(2)O (12), [Co(II)(2)(L(Tz1))(SCN)(4)]·3H(2)O (13), [Co(II)(2)(L(Tz2))(SCN)(4)]·2H(2)O (14), and [Co(II)(2)(L(Tz3))(SCN)(4)]·H(2)O (15). The tetranuclear complexes are [Cu(II)(4)(L(Tz1))(2)(H(2)O)(2)(BF(4))(2)](BF(4))(6) (1), [Cu(II)(4)(L(Tz3))(2)(H(2)O)(2)(μ-F)(2)](BF(4))(6)·0.5H(2)O (3), and [Ni(II)(4)(L(Tz3))(2)(H(2)O)(4)(μ-F(2))](BF(4))(6)·6.5H(2)O (7). Single crystal X-ray structure determinations revealed different solvent content from that found by microanalysis of the bulk sample after drying under a vacuum and confirmed that 5', 8', 9', 11', 12', and 15' are dinuclear while 1' and 7' are tetranuclear. As expected, magnetic measurements showed that weak antiferromagnetic intracomplex interactions are present in 1, 2, 4, 7, and 8, stabilizing a singlet spin ground state. All seven of the dinuclear cobalt(II) complexes, 9-15, have similar magnetic behavior and remain in the [HS-HS] state between 300 and 1.8 K.     

Two novel inorganic-organic hybrid materials constructed from two kinds of octamolybdate clusters and flexible tetradentate ligands

Two novel hybrid materials based on two kinds of octamolybdate anions and metal-organic frameworks (MOFs), namely, [Ag(8)(L(1))(4)(α-Mo(8)O(26))(β-Mo(8)O(26))(H(2)O)(3)]·H(2)O (1) and [Cu(I)(3.1)Cu(II)(0.5)(β-Mo(8)O(26))(0.5)(ζ-Mo(7)(VI)Mo(V)O(26))(0.5)(L(2))(2)(H(0.8)L(2))(0.5)] (2), where L(1) = 1,1'-(1,3-propanediyl)bis[2-(4-pyridyl)benzimidazole] and L(2) = 1,1'-(1,4-butanediyl)bis[2-(3-pyridyl)benzimidazole], have been successfully synthesized. Crystal structure analysis revealed that 1 is a three-dimensional (3D) framework constructed of silver(I)-organic sheets and two types of (Mo(8)O(26))(4-) isomers. Compound 2 is a rare 3D framework containing copper(I,II)-organic cages and 1D channels occupied by the (ζ-Mo(7)(VI)Mo(V)O(26))(5-) and (β-Mo(8)O(26))(4-) anions. The two compounds were characterized by elemental analysis, IR spectroscopy, diffuse reflectivity spectroscopy, and photoluminescent spectroscopy. In addition, the photocatalytic behavior of 1 was investigated.     

Solvent control: dinuclear versus tetranuclear complexes of a bis-tetradentate pyrimidine-based ligand

A new bis-tetradentate acyclic amine ligand L(Et) has been synthesized from 4,6-bis(aminomethyl)-2-phenylpyrimidine and 2-vinylpyridine. Dinuclear complexes, Mn(II)(2)L(Et)(MeCN)(H(2)O)(3)(ClO(4))(4) (1), Fe(II)(2)L(Et)(H(2)O)(4)(BF(4))(4) (2), Co(II)(2)L(Et)(H(2)O)(3)(MeCN)(2)(BF(4))(4) (3), Ni(II)(2)L(Et)(H(2)O)(4)(BF(4))(4) (4), Ni(II)(2)L(Et)(H(2)O)(4)(ClO(4))(4)·8H(2)O (4'), Cu(II)(2)L(Et)(BF(4))(4)·MeCN (5), Zn(II)(2)L(Et)(BF(4))(2)(BF(4))(2)·?MeCN (6), were obtained from 1 : 2 reactions of L(Et) and the appropriate metal salts in MeCN, whereas in MeOH tetranuclear complexes, Mn(II)(4)(L(Et))(2)(OH)(4)(ClO(4))(4) (7), Fe(II)(4)(L(Et))(2)(F)(4)(BF(4))(4)·5/2H(2)O (8), Co(II)(4)(L(Et))(2)(F)(4)(BF(4))(4)·3H(2)O (9), Ni(II)(4)(L(Et))(2)(F)(4)(BF(4))(4)·4H(2)O (10), Cu(II)(4)(L(Et))(2)(F)(4)(BF(4))(4)·3H(2)O (11) and Zn(II)(4)(L(Et))(2)(F)(4)(BF(4))(4) (12), result. Six complexes have been structurally characterized: in all cases each L(Et) is bis-tetradentate and provides a pyrimidine bridge between two metal centres. As originally anticipated, complexes 1, 4' and 6 are dinuclear, while 9, 10 and 12 are revealed to be tetranuclear, with two M(2)(L(Et))(4+) moieties bridged by two pairs of fluoride anions. Weak to moderate antiferromagnetic coupling between the metal centres is a feature of complexes 2, 3, 4, 8, 9 and 10. The dinuclear complexes 1-6 undergo multiple, mostly irreversible, redox processes. However, the pyrimidine-based dicopper(II) complex 5 undergoes a two electron quasi-reversible reduction, Cu(II)(2)→ Cu(I)(2), and this occurs at a more positive potential [E(m) = +0.11 V (E(pc) = -0.03 and E(pa) = +0.26 V) vs. 0.01 M AgNO(3)/Ag] than for either of the dicopper(II) complexes of the analogous pyrazine-based ligands.     

Inorganic-organic hybrid compounds based on octamolybdates and multidentate N-donor ligand: syntheses, structures, photoluminescence and photocatalysis

Six inorganic-organic hybrid compounds, namely, [Cu(2)(2,4'-tmbpt)(2)(β-Mo(8)O(26))(H(2)O)(2)]·7H(2)O (), [Cu(2,4'-tmbpt)(γ-Mo(8)O(26))(0.5)(H(2)O)]·H(2)O (), [Co(2,4'-Htmbpt)(2)(γ-Mo(8)O(26))(H(2)O)(2)] (), [Zn(2,4'-Htmbpt)(2)(γ-Mo(8)O(26))(H(2)O)(2)] (), [Ni(2,4'-tmbpt)(α-Mo(8)O(26))(0.5)(H(2)O)]·2.5H(2)O () and [Ag(2,4'-Htmbpt)(β-Mo(8)O(26))(0.5)] (), have been synthesized under hydrothermal conditions (2,4'-tmbpt = 1-((1H-1,2,4-triazol-1-yl)methyl)-3-(2-pyridyl)-5-(4-pyridyl)-1,2,4-triazole). The structures of compounds have been determined by single-crystal X-ray diffraction analyses and characterized by infrared spectra (IR), elemental analyses, powder X-ray diffraction (PXRD) analyses and thermogravimetric analyses (TGA). Compound shows a 3D (3,4)-connected framework constructed by the 2D Cu(ii)-organic fragments and [β-Mo(8)O(26)](4-) anions. Compound exhibits a 2D layer structure based on Cu(ii)-organic chains and [γ-Mo(8)O(26)] chains. The layers are extended into a 3D supramolecular framework by hydrogen-bonding interactions. Compounds and are isostructural, and display 1D chain structures. The chains are further interlinked by hydrogen-bonding interactions to form 3D supramolecular architectures. Compound shows a 3D framework based on the 2D Ni(ii)-organic fragments and [α-Mo(8)O(26)](4-) anions. In compound , the 1D chains constructed by the Ag(i) ions, 2,4'-Htmbpt ligands and [β-Mo(8)O(26)](4-) anions are extended by hydrogen-bonding interactions into a 2D supramolecular layer. Each layer threads into the adjacent layers, yielding a 2D → 3D interdigitated structure. Moreover, the photoluminescent properties of and , the optical band gaps of , and the photocatalytic properties of have also been investigated.     

Microwave-assisted construction of ferromagnetic coordination polymers of [W(V)(CN)8]3- with Cu(II)-pyrazole synthons

The microwave-mediated self-assembly of [W(V)(CN)(8)](3-) with Cu(II) in the presence of pyrazole ligand resulted in the formation of three novel assemblies: Cu(II)(2)(Hpyr)(5)(H(2)O)[W(V)(CN)(8)](NO(3))·H(2)O (1), {Cu(II)(5)(Hpyr)(18)[W(V)(CN)(8)](4)}·[Cu(II)(Hpyr)(4)(H(2)O)(2)]·9H(2)O (2), and Cu(II)(4)(Hpyr)(10)(H(2)O)[W(V)(CN)(8)](2)(HCOO)(2)·4.5H(2)O (3) (Hpyr =1H-pyrazole). Single-crystal X-ray structure of 1 consists of cyanido-bridged 1-D chains of vertex-sharing squares topology. The structure of 2 reveals 2-D hybrid inorganic layer topology with large coordination spaces occupied by {Cu(Hpyr)(2)(H(2)O)(4)}(2+) ions. Compound 3 contains two types of cyanido-bridged 1-D chains of vertex-sharing squares linked together by formate ions in two directions forming hybrid inorganic-organic 3-D framework (I(1)O(2)). The magnetic measurements for 1-3 reveal a weak ferromagnetic coupling through Cu(II)-NC-W(V) bridges.     

Two novel heterometallic Cu(II)-Sr(II) coordination polymers based on 3,5-pyrazoledicarboxylic acid: synthesis, crystal structures and magnetic properties

The syntheses, crystal structures and magnetic properties are described for two novel 2D heterometallic Cu(II)-Sr(II) coordination polymers {Sr(H(2)O)(6)[(Im)(4)Cu(4)(pdc)(4)Sr(H(2)O)(4)]·6H(2)O}(n) (1) and [Cu(2)(H(2)O)(2)(pdc)(2)Sr(H(2)O)(3)](n) (2) (H(3)pdc = 3,5-pyrazoledicarboxylic acid; Im = imidazole). The 1 : 1 : 1 : 5 reaction of SrCl(2)·6H(2)O, Cu(NO(3))(2)·3H(2)O, H(3)pdc and imidazole in H(2)O-EtOH at 120 °C under autogenous pressure gave 1. Complex 2 was obtained from the 1 : 1 : 1 H(3)pdc/Sr(OH)(2)·8H(2)O/Cu(NO(3))(2)·3H(2)O reaction mixture in H(2)O-EtOH under solvothermal conditions. Complex 1 can be described as a 2D grid-shaped network with the four Cu(II) ions in a saddle-like conformation. In complex 2, Sr(II) ions link metalloligands [Cu(2)(pdc)(2)(H(2)O)(2)](2-) to generate a 2D layer framework. Variable-temperature solid-state dc magnetic susceptibility studies have been performed in the temperature range 2.0-300 K for complexes 1 and 2. Antiferromagnetic Cu(II)···Cu(II) exchange interactions were found for both 1 and 2.