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Three series of copper hydride clusters [Cu 8 H 6 L 6 ] 2+ (1), [Cu 4 HX 2 L 4 ] + where X - = Cl - (2a), Br - (2b), I - (2c), N 3 - (2d) and SCN - (2e), and [Cu 4 HX 3 L 3 ] where X - = Br - (3b) and I - (3c) (L = 2-(diphenylphosphino)pyridine, dppy) were synthesized and characterized by single-crystal X-Ray crystallography and standard spectroscopic techniques. The metal core of 1, Cu 8 , can be described as a bicapped octahedron, while those of 2 and 3 series adopt tetrahedral structures. The hydride positions were deduced from difference electron density maps and corroborated by NMR and DFT calculations. For 1, there are two μ 4 -H - , one each in the two tetrahedral cavities of the two capping atoms and four μ 3 -H - on the six triangular faces around the waist of the octahedron. For [Cu 4 HX 2 L 4 ] + and [Cu 4 HX 3 L 3 ] series, the single μ 4 -H - resides in the center of the Cu 4 tetrahedron. It was found that these three series of copper clusters are intimately connected and can convert from one to another under specific reaction conditions. Their transformation pathways were investigated in detail. Spontaneous resolution to form optically pure enantiomeric single crystals was observed for [Cu 4 H(SCN) 2 L 4 ] + (2e) and [Cu 4 HBr 3 L 3 ] (3b). Photoluminescence was observed for [Cu 4 HX 2 L 4 ] + , as well as [Cu 4 HX 3 L 3 ] with strong emissions from green to yellow regions.

A tripodal amide based ligand, tris-{(2-carbamoyl-5-carbomethoxy-pyridine)-2-ethyl}amine (H3L, 1), was synthesized and structurally characterized by single crystal X-ray diffraction. Investigation of the cation recognition behavior showed that the ligand has selective colorimetric sensing properties for cobalt(II) ions by an obvious color change from colorless to yellow. To investigate the sensing mechanism of H3L for Co(2+) ions, UV-vis absorption spectroscopy and single-crystal structural analysis were performed. The mixture of the ligand and cobalt(II) ions displayed selective colorimetric sensing properties for weak acid anions, such as CO3(2-), Ac(-), HCO3(-), SO3(2-), and PO4(3-). Detailed (1)H NMR experiments revealed that the basicity of the anions played an important role in the intensity of the interaction between the ligand and anions. The structures of compounds CoL (2), Co-Ac-HL (3), H4L-NO3 (4), and H4L-ClO4 (5) were also determined by single crystal diffraction studies.

Two homochiral coordination polymers, namely, [Yb(III)(3)Mn(III)(6)(L)(6)(μ(2)-OMe)(6)(isonicotinate)(2)(HOMe)(2)][Yb(III)(3)Mn(III)(6)(L)(6)(μ(2)-OMe)(6)(isonicotinate)(2)(HOMe)(4)](NO(3))(2)·6MeOH·12H(2)O (5) (H(3)L = (S,E)-4-(2-hydroxybenzylideneamino)-2-hydroxybutanoic acid) and [Yb(III)(3)Mn(III)(6)Na(L)(6)(μ(2)-OMe)(6)(OOCH)(3)]I·17H(2)O (6), have been constructed by utilizing a stable enantiopure [Yb(III)(3)Mn(III)(6)(L)(6)(μ(2)-OMe)(6)](3+) (Yb(3)Mn(6)) cluster as a precursor.

An undeca-nuclear nickel substituted POM, namely [Ni(H(2)O)(6)][Ni(11)(PW(9)O(34))(2)(IDA)(3)(en)(2)(Hen)(2)(OH)(6)]·(H(2)O)(7)·(H(2)en)(2) (1) (en = 1,2-ethylenediamine, H(2)IDA = iminodiacetic acid), was synthesized through hydrothermal reaction of Na(6)PW(9)O(34), en, H(2)IDA and NiCl(2)·6H(2)O. Single-crystal structure reveals that 1 can be viewed as Ni(6)PW(9) and Ni(5)PW(9) units linked by a μ(3)-O bridge and two IDA(2-) ligands. Magnetic investigation indicates the presence of dominantly ferrimagnetic interactions within the Ni(11) core. Electrochemistry study shows that 1 displays a stable and reproducible voltammetric graph.

Diallylmelamine combines with Ag(2)O and auxiliary polycarboxylates to give three stable crystalline network structures, namely, [Ag(2)(dama)(2)(nipt)·H(2)O·C(2)H(5)OH](n) (1), [Ag(2)(dama)(glu)](n) (2), and [Ag(4)(dama)(2)(pma)·2H(2)O](n) (3), (dama = diallylmelamine, H(2)nipt = 5-nitroisophthalic acid, H(2)glu = glutaric acid, H(4)pma = pyromellitic acid), which have been successfully synthesized and characterized by elemental analysis, FT-IR Spectra, powder X-ray diffraction and thermogravimetric analyses, and single-crystal X-ray diffraction. Complex 1 is a 1D double-chain extended by μ(2)-N,N'-(η(2)-vinyl)-dama and μ(3)-nipt along the b axis. Notably, dama ligands in 1 display two coordination modes (bidentate μ(2)-N,N'-(η(2)-vinyl) and monodentate μ(1)-N) and two different conformations (cis(anti-gauche) and trans(anti-anti)). In 2, a pair of centrosymmetric glu ligands clamp two Ag(I) ions to form a half paddle-wheel [Ag(2)(COO)(2)] secondary building unit (SBU) which is further extended by μ(2)-N,N'-(η(2)-vinyl)-dama to form a 1D tape. Complex 3 is a 2D sheet built from μ(3)-N,N',N''-(η(2)-vinyl)-dama and μ(8)-pma. Interestingly, apparent silver-vinyl interactions with a η(2) mode were commonly observed in the solid-state structures of 1-3 (Ag-C = 2.311(4)-2.467(5) Å). The structural dissimilarity between 1 and 2 is caused by the different auxiliary polycarboxylates and different coordination modes of dama. In addition, the thermal stabilities and emissive behaviors of them were also investigated.

Three metal-organic frameworks, [M(3)(ip)(4)][EMIm](2) (M = Co 1, Ni 2, Mn 3, H(2)ip = isophthalic acid, EMIm = 1-ethyl-3-methyl imidazolium) were prepared from an ionic liquid medium. All the compounds feature the same (4(24))(6(4)) topology based on linear trinuclear clusters as eight-connected nodes. Compounds 1 and 2 are isostructural, while compound 3 exhibits a different structure due to the slight difference in the arrangement of M(3)(OOCR)(8) SBUs. Magnetic property measurements reveal that all the compounds display anti-ferromagnetic coupling, where compounds 2 and 3 show isotropic exchange interactions of -0.10 cm(-1) for 2 and -1.6 cm(-1) for 3. Investigation of the thermal diffusivity shows that the thermal diffusivity of 1 is higher than that of 3, while that of 3 is higher than that of 2., (This journal is © The Royal Society of Chemistry 2011)

A 2D tri-layer compound {[Co(8)(tbip)(6)(H(2)O)(9)(OH)(4)]·12(H(2)O)}(n) (1) (H(2)tbip = 5-tert-butyl isophthalic acid) consisting of novel heptacobaltate clusters and single cobalt centers bridged by tbip(2-) ligands has been hydrothermally synthesized. The complex represents a rare example of a homometallic coordination polymer built up from both heptanuclear metal clusters and single metal centers simultaneously. The magnetic investigation reveals that the complex exhibits the overall predominance of antiferromagnetic coupling between magnetic centers.

This paper discusses the synthesis of two carbon-based pyridine ligands of fullerene pyrrolidine pyridine (C(60)-py) and multi-walled carbon nanotube pyrrolidine pyridine (MWCNT-py) via 1,3-dipolar cycloaddition. The two complexes, C(60)-Ru and MWCNT-Ru, were synthesized by ligand substitution in the presence of NH(4)PF(6), and Ru(II)(bpy)(2)Cl(2) was used as a reaction precursor. Both complexes were characterized by mass spectroscopy (MS), elemental analysis, nuclear magnetic resonance (NMR) spectroscopy, infrared spectroscopy (IR), ultraviolet/visible spectroscopy (UV-VIS) spectrometry, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), and cyclic voltammetry (CV). The results showed that the substitution way of C(60)-py is different from that of MWCNT-py. The C(60)-py and a NH(3) replaced a Cl(-) and a bipyridine in Ru(II)(bpy)(2)Cl(2) to produce a five-coordinate complex of [Ru(bpy)(NH(3))(C(60)-py)Cl]PF(6), whereas MWCNT-py replaced a Cl(-) to generate a six-coordinate complex of [Ru(bpy)(2)(MWCNT-py)Cl]PF(6). The cyclic voltammetry study showed that the electron-withdrawing ability was different for C(60) and MWCNT. The C(60) showed a relatively stronger electron-withdrawing effect with respect to MWCNT., (This journal is © The Royal Society of Chemistry 2011)

An ultrasonic reaction of Ag(2)O, 4,4'-bipyridine (bipy) and (2S, 3R)-3-amino-2-hydroxybutanoic acid (L-Thr) gives an unexpected Ag(I) supramolecular framework, {[Ag(3)(bipy)(3)(cahba)]·HCO(3)·10H(2)O}(n) (1), in which the (2S, 3R)-3-(carboxyamino)-2-hydroxybutanoic acid (H(2)cahba) is a carbamate derivative of L-Thr, obtained via in situ transformation of amino group of L-Thr into carbamate by means of CO(2) uptake.

Three enantiopure isostructural sandwich-type clusters, Ln(III)(3)Mn(III)(6) (Ln = Dy (1), Tb (2) and Gd (3)) have been synthesized through reactions of a chiral Schiff-base ligand ((S,E)-4-(2-hydroxybenzylideneamino)-2-hydroxybutanoic acid, H(3)L) with manganese and lanthanide ions, showing intramolecular antiferromagnetic interaction.

Three sandwich-type silicotungstates, formulated as [Cu4(H2O)2(SiW9O34)2] x 12 NH4 x 22 H2O (1), [Cu4(H2O)2(SiW9O34)2] x 12 NH4 x 11 H2O (2) and {[Cu(NH3)4]2[Cu(H2O)4][Cu4(H2O)2(SiW9O34)2]} 2[Cu(NH3)4(H2O)] x 2 NH4 x 6 H2O (3), were synthesized by microwave irradiation and hydrothermal reaction. Crystal structural analysis reveals that 1-3 possess the same dimeric polyoxoanions [Cu2SiW9O34(H2O)]2(12-) featuring tetranuclear copper(II) clusters. Magnetic studies indicate that the Cu4 clusters exhibit ferromagnetic coupling interactions. Investigation on their catalytic activity for the oxidation of ethylbenzene suggests that catalytic activity of 1-3 is closely related to the acidity of complexes and the existence of unsaturated coordination sites in the complex.

A nanosized Gd6Ni3 cluster-based two-dimensional 3d-4f heterometallic coordination polymer has been synthesized under hydrothermal conditions using a mixture of H4PMIDA (H4PMIDA = N-(phosphonomethyl) iminodiacetic acid), Gd(ClO4)3 and Ni(CH3COO)2·4H2O. An electrical property investigation reveals that the coordination polymer exhibits a proton conductivity.

A one-dimensional iron(II) spin-crossover compound [Fe(3py-im)(2)(NCS)(2)].7H(2)O (1) (3py-im = 2,4,5-tris(4-pyridly)-imidazole) has been solvothermally synthesized and structurally characterized. Compound 1 crystallizes in the monoclinic space group P2/c with a = 11.9078(2), b = 9.9474(1), c = 17.7290(3) and beta = 102.361(2) degrees at 105 K. Studies on the variable-temperature magnetic susceptibilities and Mössbauer spectra suggest that compound undergoes incomplete spin transition behaviour. Pressure effects on the transition behaviour have also been investigated, the thermal-induced spin transition becomes more gradual and the critical temperature shifts towards slightly higher temperature range when external pressure increases. However, the spin transition can not be completed by applying external pressure even as high as 0.79 GPa.

Four Keggin-based coordination polymers, namely, {[Cu2(4,4'-bpy)(4,4'-Hbpy)4(H2O)4](SiW12O40)2(H2O)4}n (1), {[Cu2(4,4'-bpy)(4,4'-Hbpy)6(SiW12O40)3](4,4'-Hbpy)2(H2O)7}n (2), {[Cu2(mu2-H2O)2(4,4'-bpy)3(SiW12O40)](H2O)6}n (3) and {[Cu2(mu2-OH)(4,4'-bpy)3(SiW12O40)(H2O)] [Cu2(mu2-O)(4,4'-bpy)4(H2O)2]0.5 x (H2O)3}n (4) (4,4'-bpy = 4,4'-bipyridine) were prepared through the hydrothermal reaction of silicotungstic acid, copper(II) nitrate and 4,4'-bipyridine under different pH conditions. Coordination polymers 1 and 2, which exhibit 0D and 1D structures respectively, were prepared at pH = 3.5. At pH = 5.5, a 2D coordination polymer 3 was obtained. Increasing the pH of the reaction to 8.5 led to a 3D coordination polymer 4. The structural diversities of 1-4 reveal that the pH value of the reaction plays a key role in the assembly of POM-based coordination polymers. Investigation of the catalytic properties of 1-4 for the oxidation of ethylbenzene indicates that the catalytic activity of the coordination polymers is closely related to the protonated extent of 4,4'-bpy in the coordination polymers.

The reaction of cucurbit[6]uril with Cu(NO3)2 and CuCl2, respectively, generates a 1D zigzag chain of {[Cu(H2O)4(cucurbit[6]uril)].(NO3)2.(H2O)8}n and a 1D tubular structure of {[Cu(H2O)2(Cl)2(cucurbit[6]uril)](1/3).(H2O)3}n, showing clearly how to control the reversible and mutual interconnections between ligand and metal ion under the guide of coordination chemistry.

A novel cobalt compound [Co(9)(HL)(4)(L)(4)Cl(2)] x (EtOH)(2)(H(2)O)(2) (H(3)L = (E)-2-2((1,3-dihydroxy-2-methylpropan-2-ylimino)methyl) phenol) has been solvothermally synthesized and structurally characterized. The compound crystallised in the space group C2/c with a = 32.624(2) A, b = 9.4814(4) A, c = 33.395(2) A, beta = 109.339(5) degrees and V = 9746.8(9) A(3). The crystal structure is a mixed-valence nonanuclear Co(II/III) oligomer, which contains a square-pyramidal Co(II)(5) core formed through mu(4)-Cl and mu(3)-alkoxo bridges and the pentanuclear Co(II)(5) core is surrounded by four peripheral Co(III) ions at the square-pyramidal base plane through mu(2)-alkoxo bridges. Magnetic properties of the compound can be considered as the magnetism of the Co(II)(5) core, and the superexchange interactions between Co(II) ions within the core were calculated with three Co(II)-Co(II) superexchange parameters by using MAGPACK software package to give J(1) = + 11.1 cm(-1), J(2) = -6.50 cm(-1), J(3) = -3.25 cm(-1), D = + 6.0 cm(-1) and g = 2.30.

A cage-shaped 3d-4f heterometallic ferromagnetic cluster, consisting of six Ni(ii) and three La(iii) ions, was synthesized by microwave irradiation. The magnetic susceptibilities of the cluster were fitted with the help of the program MAGPACK, revealing that the magnetic exchange in the cluster is closely related to the coordination mode and spatial distribution between the metal ions.

The reaction of iminodiacetic acid with Ln2O3 (Ln = Dy, Ho, Er, Yb) under hydrothermal conditions generate a series of 3D lanthanide-based coordination polymers, in which, the iminodiacetic acid (IDA) was transformed into a 2,5-diketopiperazine-1,4-diacetate.

Solvothermal reaction of Co(OAc)2.4H2O with H4L (H4L = 2-((2-hydroxybenzylidene)amino)-2-hydroxymethylpropane-1,3-diol) in MeCN gave a mixed-valence pentanuclear cobalt complex [Co5(HL)2(H2L)2(OAc)2].2.5H2O. Crystal structural analysis revealed that two Co(III) ions were linked to a central triangular Co(II) core through HL(3-) and H2L(2-) hydroxyl groups. Magnetic measurements showed interesting magnetic properties that were assigned to spin-orbital coupling and ferromagnetic exchange interactions.

Hydrothermal reaction of La(NO(3))(3), NaHCO(3) and H(3)L (H(3)L = pyrazole-3,5-dicarboxylic acid) gives a 3D metal-organic framework with a dynamic porous property.

[Ag(UO2)3 (OAc)9][Zn(H2O)4(CH3CH2OH)2] (, OAc = CH3COO-) crystallized from an ethanol solution and its structure was determined by IR spectroscopy, elemental analysis, 1H NMR, 13C NMR and X-ray crystallography; it is composed of [Zn(H2O)4(CH3CH2OH)2]2+ cations and [Ag(UO2)3(OAc)9]2- anions in which triuranyl [(UO2)(OAc)3]3 clusters are linked by the Ag ion.