Molecular assembly of novel hetero-metal clusters: [(O=MoS3Cu2)2(μ-Sn2S6)]4− and [(S=MoS3Cu2)3(μ3-S)2]4−

Two mixed molybdenum–copper–sulfur clusters containing two or three {E=MoS₃Cu₂} (E=O, S) fragments have been assembled around the nucleophiles μ₂-Sn₂S₆⁴⁻ or μ₃-S²⁻, viz. [(MoES₃Cu₂)₂(μ-Sn₂S₆)]⁴⁻ (E=0.7 O + 0.3 S) and [(MoS₄Cu₂)₃(μ₃-S)₂]⁴⁻.     

A novel 3D coordination polymer [Cd15(μ4-Mtta)12(μ3-Mtta)6(μ3-SO4)4(μ3-OH)4]: Synthesis,structure and solid properties

A 3D coordination polymer, {[Cd₁₅(μ₄-Mtta)₁₂(μ₃-Mtta)₆(μ₃-SO₄)₄(μ₃-OH)₄] · 6H₂O}_n (1) (Mtta = 5-methyl-tetrazolate), which shows the rare multifunction of in situ formed Mtta and bright photo-induced blue emission, was isolated from a hydrothermal reaction of CdSO₄ · 8/3H₂O, NaN₃ in acetonitrile and water.     

Ru4(μ-CO)(CO)9(η4-μ4-C6H4)(η2-μ1,μ4-PPhCH2CH2PPh2): an unusual pyrolysis product of Ru3(CO)10(dppe) containing a benzyne ligand

The thermal decomposition of Ru₃(CO)₁₀(dppe) in refluxing benzene gives, in contrast to the pyrolysis of the dppm analogue, the tetranuclear cluster Ru₄(μ-CO)(CO)₉(η⁴-μ₄-C₆H₄)(η²-μ₁,μ₄-PCH₂CH₂PPh₂) (1) along with Ru₃(CO)₉(η²-μ₁,μ₂-C₆H₅)(η³-μ₁,μ₂-PPhCH₂CH₂PPh₂) (2). The single-crystal structure analysis of 1 reveals a square-planar tetraruthenium skeleton containing a η⁴-μ₄-benzyne ligand as well as a η²-μ₁,μ₄-phosphinidene–phosphine ligand.     

Synthesis,characterization and weak ferromagnetic coupling in [Cu2(μ3-CO3)(SCN)2(py)4]n

The crystal structure of a novel [Cu₂(μ₃-CO₃)(SCN)₂(py)₄]_n complex has been determined. It comprises of [CuCO₃Cu]_n infinite chains, running along the a-axis, and is in this aspect similar to the previously described [Cu(CO₃)(4-aminopyridine)₂]·H₂O complex. The FTIR spectrum of [Cu₂(μ₃-CO₃)(SCN)₂(py)₄]_n has been recorded and analyzed. A CuCO₃Cu intrachain coupling between Cu(II) atoms has been found to be responsible for the weak ferromagnetic properties of [Cu₂(μ₃-CO₃)(SCN)₂(py)₄]_n.     

A photoluminescent metallophane [Cu2(μ-dppb)2(CH3CN)4](BF4)2 with a chair conformation: synthesis,structural and spectroscopic studies

A dinuclear copper(I) complex [Cu₂(μ-dppb)₂(CH₃CN)₄](BF₄)₂ (dppb=1,4-bis(diphenylphosphino)benzene) has been prepared and characterized by X-ray crystallography, absorption and luminescence spectrometry. The two copper atoms are double linked by two dppb ligands to form a metallophane with the two bridging phenyl rings parallel to each other. The core cyclophane-like structure adopts a chair conformation constructed by four coplanar P atoms and two phenyl rings from two dppb ligands, and the two copper atoms located above and below the mean plane. At room temperature, the complex in solid state exhibits photoluminescence originated from the intraligand excited state perturbed by copper coordination. The title complex may serve as a pre-organized dimetal building block for constructing novel supramolecular system.     

Rapid phosphorus–nitrogen bond cleavage in bis(diphenylphosphino)amine. Synthesis,X-ray structure and electrochemical characterization of [Ni2(μ2-Ph2P)(μ2-Ph2PNHPPh)2(CNR)2]X,R=Me,n-Bu,Xylyl; X=Cl,I, BPh4 binuclear Ni(I) complexes

Ni(II) reacts with Ni(0) complexes in toluene solution to yield diamagnetic phosphido-bridging Ni(I)–Ni(I) complexes of the type Ni₂(μ²-PPh₂)(CNR)₂(μ²-dppa)₂. The great thermodynamic stability of these complexes is discussed on the light of their electrochemical properties. The X-ray crystal structure of the complexes Ni₂(μ²-PPh₂)(CNR)₂(μ²-dppa)₂, R=n-Bu, Xylyl is also presented.     

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.     

Thermal dehydration of Y(TFA)3(H2O)3: Synthesis and molecular structures of [Y(μ,η1:η1-TFA)3(THF)(H2O)]1∞ · THF and [Y4(μ3-OH)4(μ,η1:η1-TFA)6(η1-TFA)(η2-TFA)(THF)3(DMSO)(H2O)] · 6THF (TFA = trifluoroacetate)

In order to obtain a better anhydrous precursor for various applications in materials science and catalysis, thermal dehydration reactions of Y(TFA)₃(H₂O)₃ (TFA = trifluoroacetate) (A) were investigated. Thermal treatment of A at different temperatures under vacuum (5 × 10^?2 mm) for several hours failed to give totally anhydrous yttrium trifluoroacetate (as indicated by IR). Two different complexes, a partially dehydrated [Y(μ,η¹:η¹-TFA)₃(THF)(H₂O)]_1∞·THF (1) and a partially hydrolyzed [Y₄(μ₃-OH)₄(μ,η¹:η¹-TFA)₆(η¹-TFA)(η²-TFA)(THF)₃(DMSO)(H₂O)] · 6THF (2), were obtained with good and moderate yield, respectively, by crystallization of two different thermally treated batches of A from THF (or THF + DMSO) at room temperature. More efficient dehydration of A could be achieved at 200 °C in a furnace, the obtained anhydrous yttrium tris-trifluoroacetate giving Y(TFA)₃(THF)₂ (3) on crystallization from THF. All the products were characterized by elemental analyses, FT-IR and ¹H NMR spectroscopy as well as thermo-gravimetric analysis. In addition, single crystal X-ray structures are reported for 1 and 2, which show either a terminal (η¹ and η²) or bridging (μ,η¹:η¹) bonding behavior of the TFA ligand.     

Analysis of the Composition of CuI–As2Se3 and CuI–PbI2–As2Se3 Chalcogenide Films by X-ray Fluorescence Spectroscopy

The chalcogenide films As₂Se₃, CuI–As₂Se₃, and CuI–PbI₂–As₂Se₃ are prepared through chemical deposition from an organic solvent and investigated by X-ray fluorescence spectroscopy. The contents of the main components of the chalcogenide films are compared by analyzing the intensity ratios for the AsK , SeK , and CuK lines. It is found that the content of the main components (As, Se, and Cu) is virtually the same in binary chalcogenide, pseudobinary, and multicomponent chalcogenide systems, no matter what the technique used for preparing the materials (films deposited from solutions of chalcogenide glasses in n-butylamine and bulk glasses). This result is consistent with a model of dissolution of vitreous semiconductors in organic bases (amine) according to which the fundamental properties of bulk glasses remain unchanged upon formation of the films. The experimental data indicate an analogy between the properties of the multicomponent chalcogenide glasses CuI–As₂Se₃ and CuI–PbI₂–As₂Se₃ and the chalcogenide glass–based films.     

Synthesis,structure and magnetic properties of a trinuclear cyano-bridged complex [Cu(bappz)(μ-NC)Ni(CN)2(μ-CN)Cu(bappz)](ClO4)2 {bappz=1,4-bis(3-aminopropyl)piperazine}

The bimetallic trinuclear complex [Cu(bappz)(μ-NC)Ni(CN)₂(μ-CN)Cu(bappz)](ClO₄)₂ (bappz=1,4-bis(3-aminopropyl)piperazine) has been prepared from the reaction of [Cu(bappz)](ClO₄)₂ and K₂[Ni(CN)₄] in water and its crystal and molecular structure has been determined. The structure consists of a trinuclear [Cu(bappz)(μ-NC)Ni(CN)₂(μ-CN)Cu(bappz)]²⁺ cation and two perchlorate anions. The bridging [Ni(CN)₄]²⁻ anion is coordinated by two [Cu(bappz)]²⁺ cations through two cyano groups, providing a novel trinuclear structure with the Cu–(NC)–Ni–(CN)–Cu linkage. The nickel(II) ion is four-coordinated by carbon atoms from four cyano groups (two of them, in trans position, form a bridge) in a square planar arrangement, whereas both the copper(II) ions are five-coordinated by four bappz nitrogens and one cyanide nitrogen in a distorted square–pyramidal geometry. The temperature dependence of magnetic susceptibility was measured for this compound over the range of 2–300 K. The magnetic investigation showed the presence of a very weak antiferromagnetic interaction (superexchange interaction parameter J=−0.54 cm⁻¹) between the copper atoms through the diamagnetic [Ni(CN)₄]²⁻ ion.     

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.     

Unexpected fragmentation of the Fe3(CO)9(μ3-Se)(μ3-AsCH3) cluster core in the reaction with CpCo(CO)2: synthesis and structure of Fe3(CO)6(μ3-Se)(μ-AsCH3{CpFe(CO)2})2(μ-CO)

The [Fe₃(CO)₆(μ₃-Se)(μ-AsCH₃{CpFe(CO)₂})₂(μ-CO)] (Cp=η⁵-C₅H₅) cluster has been obtained by the reaction of [Fe₃(CO)₉(μ₃-Se)(μ₃-AsCH₃)] with [CpCo(CO)₂]. Its crystal and molecular structures have been determined by X-ray analysis.     

Sandwich type organic-inorganic hybrid of 3d–4f heterometallic containing germanotungstates [{Cu2(1,10-phen)2(μ-CH3COO)2}Ln(α-GeW11O39)2]11 −: Syntheses,crystal structures,magnetic and photoluminescence properties

Alkali salts of organic-inorganic hybrid 3d-4f heterometallic containing derivatives of sandwich type germanotungstates: [{Cu₂(1,10-phen)₂(μ-CH₃COO)₂}Ln(α-GeW₁₁O₃₉)₂]^11 − [Ln = Pr^III (1a), Nd^III (2a), Sm^III (3a), Eu^III (4a), Gd^III (5a); 1,10-phen = 1.10-phenanthroline] have been prepared in the aqueous potassium acetate buffer (pH 4.7) solution. All these compounds were synthesized following by one pot reaction procedure under mild reaction conditions. All compounds were isolated as mixed alkali sodium/potassium salts from the solution and used for further structural characterization by single crystal XRD, powder-XRD, FT-IR, liquid UV/vis, solid state photoluminescence spectroscopy and thermo-gravimetric analysis. FT-IR spectra and powder-XRD pattern suggest that all compounds (1a–5a) are isomorphous. Further single crystal XRD analysis shows that all these compounds exhibit sandwich-type [Ln(α-GeW₁₁O₃₉)₂]^13 − structural feature in the polyoxoanions as the fundamental building block units, and the copper complexes coordinated with 1,10-phen and acetate ligands are coordinated to the terminal oxygen of the polyanion. The compounds 1a, 3a and 4a show good photoluminescence properties at room temperature. The compound 5a shows weak ferromagnetic behavior.     

Isostructural organic–inorganic hybrids of P,P′-diphenyl-methylenediphosphinate (CH2(P(Ph)O2)2)2− with divalent transition metals

New organic–inorganic hybrid materials have been synthesized by reaction in water solution of manganese, cobalt or nickel acetates with P,P^′-diphenylmethylenediphosphinic acid and all the two-dimensional structure coordination polymers obtained have been found to be isomorphous.     

Microstructure–conductivity relationship of Na3Zr2(SiO4)2(PO4) ceramics

The ionic conductivity of solid electrolytes is dependent on synthesis and processing conditions, ie, powder properties, shaping parameters, sintering time (t_s), and sintering temperature (T_s). In this study, Na₃Zr₂(SiO₄)₂(PO₄) was sintered at 1200 and 1250°C for 0-10 hours and its microstructure and electrical performance were investigated by means of scanning electron microscopy and impedance spectroscopy. After sintering under all conditions, the sodium super-ionic conductor-type structure was formed along with ZrO₂ as a secondary phase. The microstructure investigation revealed a bimodal particle size distribution and grain growth at both T_s. The density of samples increased from 60% at 1200°C for 0 hours to 93% at 1250°C for 10 hours. The ionic conductivity of the samples increased with t_s due to densification and grain growth, ranging from 0.13 to 0.71 mS/cm, respectively. The corresponding equivalent circuit fitting for the impedance spectra revealed that grain boundary resistance is the prime factor contributing to the changing conductivity after sintering. The activation energy of the bulk conductivity (E_a,bulk) remained almost constant (0.26 eV) whereas the activation energy of the total conductivity (E_a) exhibited a decreasing trend from 0.37 to 0.30 eV for the samples with t_s = 0 and 10 hours, respectively—both sintered at 1250°C. In this study, the control of the grain boundaries improved the electrical conductivity by a factor of 6.