[(η6-p-PriC6H4Me)2Ru2Mo2O6(OMe)4]: a new tetranuclear mixed-metal oxo cluster presenting a cube-based chair structure

The title complex was obtained by reaction of [(η⁶-p-PrⁱC₆H₄Me)₄Ru₄Mo₄O₁₆] with methanol in the presence of p-hydroquinone. It contains an Mo₂Ru₂O₂(OMe)₄ core consisting of two Mo₂RuO(OMe)₃ half-cubes fused together to form a chair-like structure.     

Tetra-hafnium(IV) cluster cation sandwiched between 2 di-lacunary Dawson polyoxotungstate anions: Synthesis and structure of [Hf4(μ3-O)2(μ-OH)2(H2O)4(P2W16O59)2]14−

The title polyoxometalate (POM) 1 was obtained by a 1:2 molar-ratio reaction of tri-lacunary Dawson POM [B-α-P₂W₁₅O₅₆]^12? with Hf(SO₄)₂ or HfCl₄ in an aqueous solution, and isolated as dimethylammonium salt (Me₂NH₂-1) and, also, as sodium salt (Na-1). These compounds were unambiguously characterized by complete elemental analysis, including sodium and oxygen analyses, TG/DTA, FTIR, single-crystal X-ray structure analysis, (solid-state and solution) ³¹P NMR and solution ¹⁸³W NMR spectroscopy. X-ray crystallography revealed that 1 with C_i symmetry was composed of a tetra-Hf^IV cluster cation species [Hf₄(μ₃-O)₂(μ-OH)₂(H₂O)₄]¹⁰⁺ sandwiched between 2 di-lacunary Dawson polyoxometalates (POMs), [P₂W₁₆O₅₉]^12?, and it was isostructural with the previously reported Zr₄ analogue. Thus, a pair of Hf- and Zr-containing POMs belonging to the same structure-family was built up.     

Synthesis,structure and characterization of a new nonlinear optical calcium borate [Ca2B5O9]·[H(OH)2]

A new nonlinear optical crystal [Ca₂B₅O₉]·[H(OH)₂] (1) has been synthesized under hydrothermal condition. Compound 1 crystallizes in the monoclinic space group C2 with lattice constants a = 10.111(2) Å, b = 7.754(11) Å, c = 6.198(14) Å, β = 127.04(3)° and Z = 2. The fundamental building block (FBB) of 1 is a [B₅O₁₂] unit with two BO₃ triangles and three BO₄ tetrahedra. 1 was characterized by single-crystal X-ray diffraction, IR and UV–Vis spectroscopy, thermogravimetric analysis (TGA), powder X-ray diffraction (PXRD) respectively. Also, powder second harmonic generation (SHG) measurements indicate that 1 is phase matchable and displays a SHG response of about 3.5 times that of KDP (KH₂PO₄).     

Synthesis and structure of the pentanuclear mixed-metal cluster [Co4MoCp(μ3-SBut)(μ3-S)(μ3-CO)(μ-CO)2(CO)6]

The pentanuclear mixed-metal cluster [Co₄MoCp(μ₃-SBu^t)(μ₃-S)(μ₃-CO)(μ-CO)₂(CO)₆] (1) has been synthesised by reaction of [CoMoCp(CO)₇] with Bu^tSSBu^t. X-ray structural analysis identified an asymmetric unit with three cobalt atoms and one molybdenum forming an irregular tetrahedron while one cobalt–molybdenum edge is bridged by a cobalt atom. Crystal data: space group P2(1)/n, a=10.162(2), b=13.722(3), c=17.69(5) Å, β=91.44(2)°, Z=4.     

Synthesis,spectroscopic studies and structure prediction of the new Tb(3-NH2PIC)3·3H2O complex

The synthesis, spectroscopic properties and structure prediction of the complex of Tb(III) with 3-aminopyridine-2-carboxylic acid (3-NH₂PIC) are described. The complex was characterized by elemental analysis and IR, absorption and emission spectra. The C, H and N elemental analysis consistent with the formulation of the compound as Tb(3-NH₂PIC)₃·3H₂O. This complex exhibits a luminescence intensity that is attenuated to that of its Eu⁺³ congener. The Sparkle model, used for structural computations of lanthanide complexes (SMLC), was applied to the new complex. The calculation used an INDO/S-CI model for determination of the electronic spectrum.     

Synthesis,structure, and characterization of polymeric lanthanide 2-aminoterephthalate frameworks [Ln2(atp)3(H2O)2]·dmf·4H2O

X-ray crystallography reveals four isostructural lanthanide polymeric solids, [Ln₂(atp)₃(H₂O)₂]·dmf·4H₂O (atp = 2-aminoterephthalate; dmf = N,N′-dimethylformamide; Ln = La (1), Ce (2), Pr (3) and Nd (4), respectively) that are obtained from the solvothermal synthesis which are crystallized in an interesting 3D polymeric framework with a (4,4,6)-linked {4²·8⁴}{4⁴·6²}₂{4⁸·6⁶·8}₂ fsy net topology. Upon excitation at 350 nm, they all show the solid state ligand-centered luminescences but both 2 and 3 also exhibit the weak lanthanide-based characteristic emissions in the visible region at room temperature. The cyclic voltammetric investigation indicates that 2 exhibits appreciable electrochemical activity for formaldehyde.     

A novel dirhenium(III) complex with bridging picolinate and methoxide ligands from the reaction between cis-Re2(μ-O2CCH3)2Cl4(H2O)2 and picolinic acid

The reaction of cis-Re₂(μ-O₂CCH₃)₂Cl₄(H₂O)₂ with picolinic acid (Hpic) affords either the diamagnetic, metal–metal bonded, dirhenium(III) complex Re₂(μ-OMe)(μ:η²-pic)(η²-pic)₃Cl (1) or the mononuclear rhenium(V) complex ReO(η²-pic)₂Cl (2), depending on whether mixed methanol/ethanol or acetone/ethanol solvent mixtures are used. The structures of 1 and 2 have been established by X-ray crystallography. Complex 1 is unusual in having a bridging methoxide and bridging picolinate ligand in an edge-sharing bioctahedral structure in which the Re–Re bond distance of 2.4588(4) Å is unusually short for what is a formal Re–Re double bond.     

Synthesis and structure of K2[HMo6VIVVO22(NH3CH2COO)3]·8H2O: a new example of a polyoxomolybdovanadate coordinated by a glycinato ligand

A new complex of formula K₂[HMo₆^VIV^VO₂₂(NH₃CH₂COO)₃]·8H₂O has been prepared from molybdenum(VI) oxide and vanadium(V) oxide in aqueous solution by adding glycine and potassium chloride, and its structure determined by X-ray structure analysis. The molybdovanadate anion is built up of six MoO₆ edge-sharing octahedra connected into a ring centered by a VO₄ tetrahedron. The MoO₆ octahedra are in pairs linked by the bridging glycine-carboxylato ligands.     

Synthesis,structure and characterization of (NH4)2[Cu2(H2O)4(NH3CH2COO)2(NH2CH2COO)2]H2V10O28·6H2O

The decavanadate with a novel glycine–glycinato complex of copper (II) in the cationic part, (NH₄)₂[Cu₂(H₂O)₄(NH₃CH₂COO)₂(NH₂CH₂COO)₂]H₂V₁₀O₂₈·6H₂O (1), has been prepared and characterized by elemental analysis, infrared and EPR spectroscopies. The triplet X band EPR spectrum of powdered sample evidenced magnetic interaction between the Cu(II) atoms in the dimeric unit which is probably realized through the bridging water molecules in this part of the complex. A single crystal X-ray diffraction study revealed that the structure of 1 contains cationic copper complex with a rare Cu(H₂O)₂Cu double bridge. In this cation, a simultaneous bidentate N, O– and monodentate O– coordination of glycine to the same central atom was observed for the first time.     

Insights in the sol–gel processing of Pb(Mg1/3Nb2/3)O3. The synthesis and crown structure of a new lead magnesium cluster: Pb6Mg12(μ-OAc)6(μ2,η2-OAc)18(μ3,η2-OC2H4OPri)12

The synthesis and molecular structure of a Pb–Mg bimetallic acetatoalkoxide (Pb₆Mg₁₂(μ-OAc)₆(μ₂,η²-OAc)₁₈(μ₃,η²-OC₂H₄OPrⁱ)₁₂, space group R-3, a=b=30.032(2), c=18.855(2) Å, α=β=90°, γ=120°) are discussed in this article. This compound was isolated as an intermediate during the elaboration of Pb(Mg_1/3Nb_2/3)O₃ (PMN) using sol–gel process. It results from the reaction of a bimetallic Mg/Nb species with lead acetate in 2-isopropoxyethanol.     

Hydrothermal synthesis,crystal structure and physical properties of {[Gd(H2O)4(μ2-C6NO2H5)2Gd(H2O)4](μ3-C6NO2H4)2(ZnCl3)2} · 2H2O · 2Cl

A bimetallic 4f–3d tetranuclear complex {[Gd(H₂O)₄(μ₂-C₆NO₂H₅)₂Gd(H₂O)₄](μ₃-C₆NO₂H₄)₂(ZnCl₃)₂} · 2H₂O · 2Cl (1) has been synthesized via hydrothermal reaction and structurally characterized by single-crystal X-ray diffraction. Complex 1 is characterized by a tetranuclear Gd₂Zn₂ structure with the gadolinium and zinc atoms interconnected by isonicotinic acid ligands. The tetranuclear species of {[Gd(H₂O)₄(μ₂-C₆NO₂H₅)₂Gd(H₂O)₄](μ₃-C₆NO₂H₄)₂(ZnCl₃)₂} link to isolated chlorine ions and water molecules via π?π interactions and hydrogen bonds to yield a 3-D supramolecular framework. Photoluminescent investigation reveals that the title complex displays an emission in ultraviolet region. The solid-state diffuse reflectance spectra of 1 reveal the presence of a sharp optical gap of 3.66 eV.     

Synthesis,structure and properties of a new copper (II) complex, [Cu2(4,4′-bpy)5(H2O)4](ClO4)4(4,4′-bpy)(DMF)2(H2O)2

A new copper (II) complex with formula [Cu₂(4,4′-bpy)₅(H₂O)₄](ClO₄)₄(4,4′-bpy)(DMF)₂(H₂O)₂ has been synthesized by reaction of 4,4′-bpyridine (4,4′-bpy) with Cu(ClO₄)₂. While strong hydrogen bonds play central roles in the formation of the 3D structure, the combined influence of the weak interactions such as C–H?O bonds, anion?π and C–H?π interactions are also evident in the structure. The preliminary investigation on the thermal property of the complex is presented.     

A new polyborate anion, [B7O9(OH)6]3−: Self assembly,XRD and thermal properties of s-fac-[Co(dien)2][B7O9(OH)6]·9H2O

The title compound, s-fac-[Co(dien)₂][B₇O₉(OH)₆]·9H₂O (1) (dien = HN(CH₂CH₂NH₂)₂), has been prepared as a crystalline solid in moderate yield (35%) from the reaction of B(OH)₃ with [Co(dien)₂][OH]₃ in aqueous solution (10:1 ratio). The structure contains a novel polyborate anion [B₇O₉(OH)₆]^3 − which is structurally based on the known ‘ribbon’ isomer of [B₇O₉(OH)₅]^2 −, with an additional [OH]⁻ group coordinated to a B atom in one of the outer boroxole rings. Compound 1 is formed by a self-assembly process in which the cation and anion mutually template themselves from equilibrium mixtures under reaction conditions. The [B₇O₉(OH)₆]^3 − anions are H-bonded to each other in layers with ‘cavities’ suitable for the [Co(dien]₂]^3 + complex. Three [B₇O₉(OH)₆]^3 − anions are in the secondary coordination sphere (via H-bonds) of each cation, with each anion H-bonded to three cations.     

Facile synthesis and molecular structure of the tris(amine) complex [PdCl(H2NBz)3]Cl·H2O

Reaction of Na₂[PdCl₄] with three equivalents of benzylamine at room temperature led to the isolation of [PdCl(H₂NBz)₃]Cl·H₂O in near quantitative yield, a rare example of a tris(monoamine)functionalised palladium(II) centre. A crystal structure showed that the three phenyl groups lie on the same side of the PdN₃Cl plane and the metal-bound chloride is hydrogen bonded to the co-crystallised water.     

Crystal Structure and Physicochemical Properties of Two Supramolecular Compounds: (C4H8NH2)4[Mo8O26] and (NH4)Na2[AsIIIMo6O21(O2CCH2NH3)3]·8H2O

Two inorganic–organic hybrid supramolecular compounds based on polyoxometalates formulated as (C₄H₈NH₂)₄[Mo₈O₂₆] (1) and (NH₄)Na₂[As^IIIMo₆O₂₁(O₂CCH₂NH₃)₃]·8H₂O (2) have been synthesized by conventional solution method and characterized by infrared, UV–Vis and single-crystal X-ray diffraction analyses. Thermal analysis was performed to study their thermal stability. The atomic arrangement in compound (1) can be described as inorganic layers built by [Mo₈O₂₆]^4?, pyrrolidinium cations are embedded into layers. The fascinating structural feature of compound (2) is that the glycine molecules are bounded to two edge-sharing Mo centers via their carboxylate functionality leading to functionalized heteropolymolybdate [As^IIIMo₆O₂₁(O₂CCH₂NH₃)₃]^3?, extensive net hydrogen bonds between cations and anions contribute to the crystal packing. The electrochemical behavior of compound (2) has been studied.     

Synthesis and X-ray characterization of the new pentanickel cluster cation [Ni5(μ5-S)(μ3-S)2(μ2-S)(μ-CH3COO)(PPh3)5]+

By reacting Ni(CH₃COO)₂·6H₂O with H₂S in the presence of PPh₃, the new Ni/S cluster of formula [Ni₅(μ₅-S)(μ₃-S)₂(μ₂-S)(μ-CH₃COO)(PPh₃)₅]PF₆·C₇H₈·0.5CH₂Cl₂ has been isolated and characterized by X-ray diffraction analysis. Crystal data: space group P2₁/c, a=15.774(4), b=21.235(7), c=29.288(7) Å, β=95.66(4)°. The inner core consists of a square pyramid of five nickel atoms, linked together by a bridging acetate and four variously bridging sulfur ligands. The ³¹P{¹H} NMR spectra in dichloromethane solution are consistent with the above geometry.     

A novel paradodecatungstate-B compound decorated by transition metal copper,Na2Cu5(H2O)24(OH)2[H2W12O42]·10H2O: Synthesis,structure and antitumor activities

A new paradodecatungstate-B compound decorated by transition metal copper, Na₂Cu₅(H₂O)₂₄(OH)₂[H₂W₁₂O₄₂]·10H₂O (1), has been synthesized by convenient aqueous solution method and structurally characterized by single-crystal X-ray diffraction, IR spectrum, elemental analysis and TGA. The compound crystallizes in the triclinic P-1 space group with a = 10.7140(8) Å, b = 12.9476(9) Å, c = 13.6696(10) Å, α = 73.56°, β = 75.73°, γ = 67.69°, V = 1661.8(2) ų and Z = 1. In compound 1, polyanion of [H₂W₁₂O₄₂]^10 − acts as a dodecadentate ligand that links copper and sodium cations, forming a remarkable three-dimensional framework. The experiment of antitumor activities in vitro shows that the title compound exhibits remarkable inhibitory actions on human cervical carcinoma HeLa cells, ovarian carcinoma SKOV-3 cells, hepatoma HepG2 cells and neuroblastoma SHY5Y cells.     

Synthesis and nanostructure of [Mo(C6H4O2)3]·2(C4H8N2O) and the synthesis from 1,2-PDA to (C4H8N2O)

Continuing our work on the synthesis of MoO₂L₂ and MoO₃L_AL_B that show excellent anti-cancer activities in vitro, the MoL₃ have been synthesized by the solvothermal reaction of Na₂MoO₄ with catechols and 1,2-DPA in the mixed solvent of MeCN/MeOH. X-ray diffraction revealed that Mo in chiral octahedral geometry coordinate with three catechol ligands formed three five-membered rings, and the [Mo(C₆H₄O₂)₃] are linked by hydrogen bonds Mo(OC₆H₄)O…H–N(C₄H₈O)N–H…O(C₆H₄O)Mo through the by-product (C₄H₈N₂O) that are formed by one 1,2-DPA with one CO₂ on the catalysis of Mo-complex. Also, we have disassembled bulk crystal into nano-aggregates, and under TEM mono-lamella morphology of nanostructures was observed, which agrees well with the previous conclusion that the morphologies of the nano-aggregates are associated with the quantum motifs in their crystal lattices. [Mo(C₆H₄O₂)₃] have also been characterized by UV–vis spectra, cyclic voltammogram and thermogravimetric analysis.