Effects of Water and Ion-Exchanged Counterion on the FTIR Spectra of ZSM-5. II. (Cu+–CO)-ZSM-5: Coordination of Cu+–CO Complex by H2O and Changes in Skeletal T–O–T Vibrations

The 2157 cm^–1 (strong) and 2108 cm^–1 (very weak) (CO) IR bands due to Cu⁺–CO in ZSM-5 zeolite with ¹²C and ¹³C isotopes, respectively, are reversibly red-shifted by subsequent adsorption of H₂O at 293 K. On the contrary, the locally perturbed internal (T–O–T) asymmetric stretching framework vibration [ _as ^int (TOT)(Cu⁺–CO)=965 cm^–1] is reversibly blue-shifted. The courses of the band shifts revealed notable features. Charge transfers from water to Cu⁺ ions, changes in coordination spheres of Cu⁺(CO)(H₂O) _n aqua complexes and secondary (solvent-like) effects were considered to explain the results.     

Synthesis,structure, and properties of two novel copper(II) complexes, [Cu(phen)(L)2]·6H2O and [Cu(phen)3]·(ClO4)2

Two novel copper(II) complexes, namely [Cu(phen)(L)₂]·6H₂O (1) and [Cu(phen)₃]·(ClO₄)₂ (2) have been synthesized under mild condition (HL = 5-methyl-1H-pyrazole-3-carboxylic acid, phen = 1,10-phenanthroline). We report the structural evidence of discrete water decamer conformation in the solid state. These units are found to act as supramolecular glue in the aggregation of mononuclear copper(II) complex to give a three-dimensional network through hydrogen-bonding. The preliminary investigation on the thermal behavior and the anion exchange property of the complexes are presented.     

Phase Equilibria in the Sections of the Ca(NO3)2–CO(NH2)2–H2O System and Deicing Properties of Nitrate–Urea Mixtures

Theoretical Foundations of Chemical Engineering - Phase equilibria in the sections of the Ca(NO3)2–CO(NH2)2–H2O system and the deicing properties of calcium nitrate and carbamide...     

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.     

On the Possibility of Forming Complexes with the Participation of O2– Ions in Melts and Glasses of the Na2O–SiO2–Cu2O System

The structural role of copper ions in melts (glasses) of the Na₂O–SiO₂–Cu₂O–CuO system is analyzed in the framework of the acid–base concept with due regard for the geometric (the radius ratio for Cu²⁽¹⁾⁺ and O^2– ions) and energy (the mean enthalpies of the Cu²⁽¹⁾⁺–O bonds) factors. It is demonstrated that copper ions in the structure fulfill the function of modifier cations. In these melts, the Cu¹⁺–Cu²⁺ redox equilibrium can be described without regard for the formation of [Cu²⁽¹⁾⁺O_4/2]^2(3)– ionic complexes (which could be incorporated into the structure of silicon–oxygen anions) and [Cu²⁺O _b/k ]^{2 – b/k} polyhedra providing the interaction between Cu²⁺ ions and anions. The influence of the formation of these polyhedra on the redox equilibrium is considered within the formalism of chemical thermodynamics. The composition dependence of the oxygen ion exponent pO is measured by an electromotive force (emf) technique. The ratio between the numbers of copper atoms with different valences is determined by chemical analysis. The experimental data obtained are in agreement with the theoretical inferences.     

Cu(2,2‘-bipy)(H2O)V2O6的合成及结构

以硝酸铜、2,2-联吡啶及Na3VO4用水热法在170℃合成出一种钒酸铜新化合物Cu(2,2'-bipy)(H2O)V2O6(1).化合物1的结构为一种一维链状化合物,其链状结构是以[Cu(2,2'-bipy)(H2O)]2 基团将[V4O12]4-环状的结构连接而成.     

Synthesis,structure and superoxide dismutase activity of a novel tetranuclear copper(II) complex Na2[Cu4Na2(TACNTA)4(H2O)6]·(H2O)26

A novel tetranuclear copper(II) complex Na₂[Cu₄Na₂(TACNTA)₄(H₂O)₆]·(H₂O)₂₆, where TACNTA is 1,4,7-triazacyclononane-1,4,7-triacetate, was synthesized and characterized by X-ray crystallography. The result shows that each copper(II) ion is six-coordinated to three nitrogen atoms and three oxygen atoms of ligand TACNTA and adopts distorted octahedral coordination geometry. The superoxide (·O₂^?) dismutation activity of the complex was also investigated by the riboflavin–methionine–nitro blue tetrazolium assay.     

[Zn2(H2O)3(2,2′-bipy)2(btc)][Zn(H2O)(2,2′-bipy)(btc)] ·8H2O: a novel zinc–carboxylate complex consisting of independently cationic and anionic chains

A novel zinc complex, [Zn₂(H₂O)₃ (2,2^′-bipy)₂(btc)][Zn(H₂O)(2, 2^′-bipy)(btc)]·8H₂O (1), (H₃btc=1,3,5- benzenetricarboxylic acid, 2,2^′-bipy=2,2^′-bipyridine) has been prepared by hydrothermal reaction of H₃btc, Zn(CH₃CO₂)₂·2H₂O and 2,2^′-bipyridine at 180 °C and characterized by single-crystal X-ray diffraction analysis. Complex 1 consists of independently cationic and anionic chains. The hydrogen bonding interactions between chains extend 1 into a two-dimensional supramolecular architecture.     

Catalytic reactivity and surface chemistry of polyaniline(EB)–Pd–H2O systems

Catalytic reactivity and surface chemical effects induced by the presence of water in the molecular system polyaniline(EB)–Pd–H₂O were investigated. The polyaniline(EB) doped with palladium reveals its high activity and selectivity in the semihydrogenation: hexyne → hexenes (→ hexane). However, to demonstrate these effects, the specimen has to be submitted to a special treatment to lose most of its water. The XPS analysis allowed identification of the catalytically active sites of the studied system. They were ascribed to the [PdCl₄]²⁻ complex anions present at the surface of the dry specimens. This revised version was published online in August 2006 with corrections to the Cover Date.     

Heteronuclear Cu(II)–Mn(II)–Cu(II) Complex Constructed from Metallo-Ligand Through Carboxylate Oxygens: Coexistence of Water Hexamers

A heteronuclear complex of [Mn(H₂O)₄(CuL)₂]₂·4H₂O 1 (H₂L = 2-hydrogen benzaldehydeneglycylglycine) has been synthesized and characterized by IR spectra, TGA, and single crystal X-ray diffraction analysis. The molecule consists of one $\text{Mn}{(\text{H}_{2}\text{O})_{4}}^{2+}$ Mn(H₂O) ₄ ²⁺ group and two symmetric groups [CuL]^? which are connected by carboxylate oxygen atoms. A discrete water hexamer composed of a planar tetrameric water ring and two pendent water molecules acts as a ‘glue’ to assemble adjacent [CuL]^? into a two-dimensional structure.     

Mechanism of the Formation of Ba2Ti9O20-Based Phases in the Course of Solid-Phase Interaction in the BaO–TiO2(ZrO2) and Cs2O–BaO–TiO2(ZrO2) Systems

The mechanism of solid-phase interaction in the BaO–TiO₂(ZrO₂) and Cs₂O–BaO–TiO₂(ZrO₂) systems is investigated. It is established that the formation of the Ba₂Ti₉O₂₀ compound and Ba₂Ti₉O₂₀-based solid solutions is a multistage process proceeding through the formation of intermediate phases. The solid-phase interaction in the BaO–TiO₂(ZrO₂) system occurs through the formation of the BaTi₄O₉ intermediate compound. The Ba₂Ti₉O₂₀ single-phase product is formed only in the presence of ZrO₂ (0.82 mol %) upon heat treatment at a temperature of 1250°C for 5 h. In the Cs₂O–BaO–TiO₂(ZrO₂) system, the BaTi₅O₁₁ metastable intermediate phase is formed at the first stage of the solid-phase interaction. The Cs _x Ba_{2 – x/2}Ti_{9 – y} Zr _y O₂₀ single-phase solid solutions are prepared upon heat treatment at 1100°C for 1 h. It is demonstrated that, in the Ba₂Ti₉O₂₀ structure, cesium can isomorphously substitute for barium with the formation of Cs _x Ba_{2 – x/2}Ti_{9 – y} Zr _y O₂₀ solid solutions (0 x 0.8, y = 0 and 0.09).     

A novel two-dimensional network self-assembled by the narrowest ladder cations [Cu(CH3COO)(bpe)(H2O)]nn+ containing the Cu2(μ-O)2 cores and the dimeric anions [Cu2(nta)2(bpe)]2− through hydrogen-bonding interaction

A novel complex [Cu(CH₃COO)(bpe)(H₂O)]_n·n/2[Cu₂(nta)₂(bpe)] ·6nH₂O) (bpe=trans-1,2-bis(4-pyridyl)ethylene) was synthesized and characterized. The molecule structure shows that it is composed of the ladder-like double chain cations [Cu(CH₃COO)(bpe)(H₂O)]_nⁿ⁺ and the dimeric anions [Cu₂(nta)₂(bpe)]²⁻. Through bridging oxygen atom of the acetate, the Cu₂ (μ-O)₂ core is formed. The ladder-like chain cation is the narrowest ladder [3.422(3) Å]. Two-dimensional undulating network is constructed by the cations and the dimeric anions through hydrogen-bonding interactions.     

Terbium-oxalate-pyridinedicarboxylate coordination polymers suggesting the reductive coupling of carbon dioxide (CO2) to oxalate (C2O42−):[Tb2 (3,5-PDC)2(H2O)4(C2O4)]·2H2O and [Tb(2,4-PDC)(H2O)(C2O4)0.5] (PDC = pyridinedicarboxylate)

Under hydrothermal conditions, Tb(NO₃)₃·5H₂O reacted with 3,5-pyridinedicarboxylic acid (3,5-PDCH₂) to give a 3-D coordination polymer with the empirical formula of [Tb₂ (3,5-PDC)₂(H₂O)₄(C₂O₄)]·2H₂O (1). Tb(NO₃)₃·5H₂O also reacted with 2,4-pyridinedicarboxylic acid (2,4-PDCH₂) to give another 3-D coordination polymer [Tb₂ (2,4-PDC)₂(H₂O)₂(C₂O₄)] (2). The structures of both polymers have been determined by X-ray diffraction. X-ray structure analyses show that both polymers contain bridging oxalate (C₂O₄²⁻) ligands, which might have been formed by the reductive coupling of CO₂ molecules released from the PDC²⁻ ligands through the C–C bond cleavage.     

Mixed solvothermal synthesis and X-ray characterization of a layered copper coordination polymer,Cu(H2O)(1,3-BDC) · H2O (BDC=benzenedicarboxylate)

A novel copper coordination polymer, Cu(H₂O)(1,3-BDC) · H₂O was synthesized by a mixed solvothermal reaction of cupric acetate with 1,3-BDC and characterized by single-crystal X-ray diffraction. This compound crystallizes in a tetragonal space group P4/nmm with cell parameters a=19.1411(5) Å, c=6.7881(2) Å, and Z=8. Its structure contains paddle-wheel-like bi-copper clusters with the pseudo-octahedral centers of Cu(II) ion, Cu₂O₈(H₂O)₂. Every 1,3-BDC fragment links two such clusters to yield a two-dimensional open structure. It was also characterized by infrared spectroscopy, elemental analysis, inductively coupled plasma analysis, differential thermal and thermal gravimetric analyses.     

Oxidation of cobalt(II) to cobalt(III) in the presence of phosphorus and sulphur donors via –O–C bond cleavage: synthesis and structure of [CoIII(dppe)(EtOCS2)(COS2)] (dppe=1,2-bis(diphenyl phosphino)ethane)

An ethanolic solution of cobalt(II) reacts with dppe (1,2-bis(diphenyl phosphino)ethane) and etxant (ethyl xanthate) affording an intensely coloured Co^III complex, [Co^III(dppe)(etxant)(COS₂)], by eliminating [EtOC(S)(SEt)] via –O–C bond rupture. The structure of the cobalt(III) complex has been confirmed by X-ray crystallography, NMR and mass spectrometry.     

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.     

Six- and five-coordinated complexes of Co(II) with 2-(2′-pyridyl)quinoxaline. Crystal structures of the complexes [CoLCl2(DMF)] and [CoL2(H2O)2](ClO4)2·H2O·2CH3OH

Reaction of Co(II) perchlorate hexahydrate and anhydrous Co(II) chloride with the ligand 2-(2′-pyridyl)quinoxaline (L) leads to the formation of the novel five- and six-coordinated complexes CoLCl₂(DMF) (1) and [CoL₂(H₂O)₂](ClO₄)₂·H₂O·2CH₃OH (2), correspondingly. The crystal structures of the above complexes show a trigonal bipyramidal geometry around the metal atom for complex 1 and a distorted octahedral geometry for complex 2.