Organofunctional Metal Oxide Clusters as Building Blocks for Inorganic-Organic Hybrid Materials

The controlled hydrolysis of metal alkoxides in the presence of methacrylic acid results in metal oxide clusters capped by polymerizable methacrylate ligands. Radical polymerization of small portions of such clusters with organic co-monomers allows the preparation of an interesting new type of inorganic-organic hybrid polymers in which the metal oxo clusters efficiently crosslink the organic polymers chains. SAXS investigations revealed that the clusters may aggregate to form clusters of clusters. The properties of the hybrid materials, such as thermal stability, swelling, dielectric and mechanical properties, depend not only on the portion of incorporated cluster, i.e. the crosslinking density, but also on the kind of employed cluster.     

Towards Syntheses and Structures of Heterometallic Clusters Containing Tantalum-tetrachalcogenato Building Blocks

An approach to tackle the synthesis of mixed-transition metal tantalum chalcogenide clusters is described. The synthesis of 1/_∞[Li₃(TaSe₄)(MeCN)₄]_∞ (1) will in future allow the construction of Ta–Se-transition metal clusters. The potential of this route was demonstrated by the synthesis of the mixed-metal Ta–S–Fe and Ta–S–Cu complexes (Et₄N)₃[Fe₂(SPh)₄(TaS₄)] (2) and [Cu₃(TaS₄)(PPh₃)₄] (3). Dedicated to Professor Günter Schmid on the occasion of his 70th birthday.     

Syntheses, Structures, and Some Properties of Three Vanadium Selenites

Three novel vanadium selenites with the formulae [（VO2）（1,10-phenanthtoline）（SeO3H）]2 1, [（VO2）（2,2′-bipyridine）]2（SeO3） 2 and [（VO）（H2O）（SeO3）2]2（HaEDD） 3 （EDD = N1,N1′-（ethane-1,2-diyl）diethane-1,2-diamine） were hydrothermally synthesized, and characterized with elemental analysis, FT-IR spectrum, Raman spectrum, TG-DTA analysis, EPR spectra, and single-crystal X-ray diffraction analysis. Compound I belongs to the triclinic system, space group P1^- with a = 7.7527（5）, b = 9.5345（10）, c = 9.8192（8） A^°, α = 92.712（3）, β = 105.540（3）, γ = 108.154（4）°, V = 657.66（1） A^°^3, Mr = 782.22, Z = 1, F（000） = 384,μ（MoKa） = 3.544 mm^-1, R = 0.0432 and wR = 0.1142; Compound 2 is of orthorhombic system, space group F212121 with a = 7.6574（15）, b = 14.916（3）, c = 19.085（4） A, V = 2179.8（8） Aa, Mr = 605.21, Z = 4, F（000） = 1200, μ（MoKa） = 2.579 mm^-1, R = 0.0338 and wR = 0.0658; Compound 3 belongs to the triclinic system, space group P1^- with a = 9.247（2）, b = 9.659（2）, c = 7.2651（19） A^°, α = 98.171（7）, β = 103.709（5）, γ = 114.712（13）°, V = 550.9（2） A^°^3, Mr = 828.03, Z = 1, F（000） = 400, μ（MoKa） = 7.537 mm^-1, R = 0.0641 and wR = 0.2118. Compound 1 is constructed from alternating corner-shared [VO4N2] octahedra and SeO3H units, forming a dimeric vanadium unit. These assemblies are further linked into an infinite chain via hydrogen bonds along the a axis. In the structure of 2, two distinct V centers form centrosymmetric [V2O6N4] clusters through edge-sharing, and the SeO3 unit serves as a capping unit to fix the oxovanadate cluster. In the structure of 3, each [VO6] octahedron shares four oxygen atoms with adjacent Se atoms, while every SeO3 unit shares two oxygen atoms with neighboring V atoms. This connectivity of alternating VO6 and SeO3 units results in a joint-like chain. Based on the TGA analysis, these three compounds are thermally stable under 200℃ .     

Syntheses and Crystal Structures of Two New Macrocyclic Compounds

Two new macrocyclic compounds, [Cu2(L)2](ClO4)4·2CH3OH (1) and [Cu(L)](ClO4)2·2H2O (2) (L = 1,3,10,12,15,18-hexaazatetracyclodocosane) were synthesized by condensation reactions involving amines and formaldehyde in the presence of copper anion. Compound 1 crystallizes in triclinic, space group Pí with a = 10.442(2), b = 14.197(3), c = 17.388(4), α = 91.218(4), β = 90.69(3), γ = 93.756(4)o, V = 2520.4(9)3, Z = 2, F(000) = 1260, Dc = 1.589 Mg/m3, Mr = 1205.92, μ = 1.137 mm-1, λ = 0.71073, the final R = 0.0668 and wR = 0.1573 for 9703 observed reflections with I > 2σ(I). Compound 2 crystallizes in monoclinic, space group C2/c with a = 16.911(2), b = 11.4172(15), c = 27.059(4), β = 107.787(2)o, V = 4974.7(12)3, Z = 8, F(000) = 2504, Dc = 1.610 Mg/m3, Mr = 602.92, μ = 1.155 mm-1, λ = 0.71073 , the final R = 0.0419 and wR = 0.1131 for 4374 observed reflections with I > 2σ(I).     

Spectrophotometric Determination of Vanadium in Complex Materials Using N-m-TMBHA and Thiocyanate

Abstract

Vanadium(V) reacts with N-m-Tolyl-p-methoxy benzohydroxamic acid to form 1:2 (metal to ligand) complex containing a basic V=O group and an acidic V-OH group, which forms addition compounds with thiocyanate to give a hyper and bathochromic effect in chloroform. On the basis of this bathochromic effect of thiocyanate a rapid, selective and sensitive method for the spectrophotometric determination of vanadium(V) has been developed. The blue coloured complex of vanadium(V) is extractable in chloroform having absorption maxima at 580nm and max 7100 ±50 1. mole^?1 cm^?1. The method is free from interferences of Mo(VI), W(VI), Zr(IV) and has been successfully applied for the analysis of steels and other complex materials.     

Cyclodextrins as Building Blocks for Supramolecular Structures and Functional Units

Cyclodextrins are frequently used as building blocks, because they can be linked both covalently and noncovalently with specificity. Thus one, two, three, seven, fourteen, eighteen, or twenty substituents have been linked to one β-cyclodextrin molecule in a regioselective manner. Furthermore, Cyclodextrins may serve as organic host molecules. Their internal cavity is able to accommodate one or two guest molecules. Conversely, suitable guest molecules can be used to thread one, two, or many (one hundred or more) cyclodextrin rings. The resulting supramolecular structures are often formed in solution, which allows characterization by high-resolution spectroscopic methods. Chemical conversion of these structures provides molecular architectures such as catenanes, rotaxanes, polyrotaxanes, and tubes, which are not readily prepared by other methods. The particular properties of Cyclodextrins can also be employed, for example, for the chromatographic separation of complex mixtures of substances, even racemates, by molecular recognition. Cyclodextrins and their derivatives have been found to be remarkably active catalysts as well. Finally, since Cyclodextrins can favorably influence the release of drugs, many new applications will certainly be developed in the near future.     

Polyoxometalates as Inorganic Building Blocks of Multifunctional Molecular Materials

The use of polyoxometalates (pOM's) as inorganic component in the synthesis of new molecular hybrid materials is presented. Here we show that the combination of organic molecules of the tetrathiafulvalene (TTF) type or perylene (per) with POM's yields new radical salts with unprecedented structures that present interesting magnetic and/or electrical properties or coexistence of both. The first true metallic radical salt containing a POM has been prepared and characterized. We also describe the recent results obtained by combining magnetic POM's with the organometallic cation decamethylferrocene.     

Syntheses and Crystal Structures of Lanthanide Complexes of New 15-Membered Macrocyclic Ligands with Three Pendant Acetato Groups

Two new 15-memhored fimctionalized macrocycles, dioxo-polyazacydoalkanes with three pendant acetato groups, have been synthesized by the condensation reaction of DTPA dianhy-dride (DTPA = diethylenetrlamlnepentaacetic acid ) with 1,2-di-amlnopropane, ( 15-DTPA-1, 2-pn), or 1, 2-diaminocydohex-ane, (15-DTPA-1,2-cy). Their lanthanide complexes [ Ln ( 15-DTPA-1,2-pn)(H2O)]2[Ln= Eu (1), Gd (2)] and [Ln(15-DTPA-1,2-cy)(H2O)]2[Ln= Eu (3), Gd (4)] were also pre-pared. Single crystal X-ray diffraction analyses of complexes 2 and 4 show that they have dimeric structures in solid state;each metal ion is nine-coordinated in a distorted tricapped-trig-onal prism. In complex 4, the coexistence of two diastereoiso-meric molecules in the crystal lattice was observed.     

17电子钒开环夹心羰基配合物的合成及XRD,IR,EPR研究

以４种甲基取代戊二烯基为配体合成了４个过渡金属钒开环夹心羰基配合物［２，４－（ＣＨ３）２Ｃ５Ｈ５］２ＶＣＯ（Ｉ），［２，３－（ＣＨ３）２Ｃ５Ｈ５］ＶＣＯ（Ⅱ），［２－ＣＨ３Ｃ５Ｈ６］２ＶＣＯ（Ⅲ）和［３－ＣＨ３Ｃ５Ｈ６］２ＶＣＯ（Ⅳ），其中Ⅱ，Ⅲ，Ⅳ为新配合物，用Ｘ射线单晶衍射，ＩＲ，ＥＰＲ法对所合成配合物进行了结构表征，发现Ｉ具有两种晶相。     

Template Syntheses and Crystal Structures of Hexaaza Macrocyclic Complexes with C-Methyl Substituents

1 INTRODUCTION Polyaza-macrocyclic compounds with functional substituents have been extensively investigated recen- tly because of their potential applications in radioac- tive therapy, recovery of metal ions, biomimetic che- mistry, and catalysis[1, 2]. With various structures and distinctive properties, they have become significant building blocks for further chemical studies[3～6]. As far as the preparation method is concerned, metal template condensation reactions are shown to be effec…     

Syntheses and Structures of Two Copper Compounds Supported by Octamolybdate

1INTRODUCTION More and more chemists have currently been inte-rested in the transition metal oxides(so-called polyoxometalates)mainly owing to their structural varieties and promising potential applications in catalysis,biology,medicine and materials science[1].Of the various polyoxometalate structures,the most interesting one is the molybdate family with a va-riety of structural polymers including{Mo2},{Mo4},{Mo6},{Mo8}.etc.These molybdate polymersmight act as versatile building blocks …     

Syntheses and Crystal Structures of Three Novel Amino-acid-containing Polyoxomolybdosilicates

1 INTRODUCTION Polyoxometalates as metal-oxygen cluster ions have received a great deal of research due to their potential applications in catalysis, medicine and ma- terials science[1]. The modification of organic groups to the surface of polyoxoanions gives POMs more interesting character, and many derivatives of poly- oxoanions with organic ligands have been studied[2]. Particularly the potential applications of polyoxo- metalate as drugs in anti-viral and anti-AIDS have attracted t…     

Copper Carboxylate-phosphonates: Syntheses,Crystal Structures and Magnetic Properties

Two novel copper carboxyly-phosphonates, namely, Cu_(2.5)(5-pnc)(SO_4)_(0.5)(OH)(H_2O)_(0.5)(1) and Cu_(0.5)(5-pncH_2)(H_2O)_(1.5)(2)(5-pncH_3 = 5-phosphono-1-naphthalenecarboxylic acid), have been synthesized and characterized by X-ray diffraction, infrared spectroscopy, elemental analysis, and thermogravimetric analysis. In compound 1, each {PO_3C} tetrahedron is corner-shared with two {Cu(1)O_4}, two {Cu(2)O_5} and one {Cu(3)O_5},thus forming a one-dimensional inorganic chain along the c axis containing 8-membered rings of [Cu_3O_4S] and 19-membered cages of [Cu_5O_(10)P_4]. The inorganic chains are further connected by a 5-pnc~(3-) ligand to generate a three-dimensional framework. Compound 2 exhibits a one-dimensional structure, in which the inorganic chains of [Cu-O-Cu]_n are connected by the organic ligands through hydrogen bonding interactions, forming an infinite two-dimensional layer. Magnetic measurements of 1 indicate that dominant antiferromagnetic interactions are mediated between the Cu~(2+) centers.     

Synthesis,Structure and Physical Properties of an Hybrid Compound Based on Strandberg Type Polyoxoanions and Copper Cations

Single crystals of novel Strandberg type molybdophosphonate complex, (C₅H₇N₂)₆[Cu(H₂O)₃HP₂Mo₅O₂₃]₂·4H₂O, are synthesized in aqueous solution and characterized by X-ray diffraction, spectroscopy (diffuse reflectance, UV–Vis and IR) and thermal analysis. Single crystal X-ray diffraction analysis reveals that this novel compound is composed of [Cu(H₂O)₃HP₂Mo₅O₂₃]^3? anions, three distinct 2-aminopyridinium cations as counter-ions and two distinct crystallization water molecules. The crystal packing is stabilized by H-bonds and π–π interactions, resulting in a 3D framework. In addition, the magnetic behavior of the related compound is measured. Magnetic measurements from 100 to 2 K indicate the presence of an antiferromagnetic coupling between the Cu (II) ions in (C₅H₇N₂)₆[Cu(H₂O)₃HP₂Mo₅O₂₃]₂·4H₂O complex, resulting in a maximum of an antiferromagnetic–paramagnetic transition at T_N = 7 K. Magnetic susceptibility data indicate an antiferromagnetic Curie–Weiss behavior in the studied temperature range, and molecular field theory gives the (J/k_B) values of the nearest neighbor interactions between copper ions.     

Alkoxysulfanes AlkylO-S-Y as Building Blocks and Ligands

Abstract

The Thio-ARBUZOV-Reactions has proved to be a facile synthetic route for the conversion of alkoxysulfanes into sulfinyl derivatives. Scope and limitations of the reaction are discussed. BEcause of their donor properties the alkoxysulfanes are suitable ligands which has been confirmed by the preparatoin of palladium(II) complexes.     

A New Oscillating Reaction of the Belousov-Zhabotinskii-type with a Macrocyclic Copper(II) Complex as Catalyst

The reaction of bromate ion with malic acid in aqueous H₂SO₄ catalyzed by a tetraazamacrocyclic copper(II) complex exhibits oscillatory behavior. This complex contains an unsaturated macrocyclic ligand, 5,7,7,12,14,14-hexemethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene. The reactions were monitored both spectrophotometrically and potentiometrically. It was found that the oscillation period (tp) is dependent on the initial concentrations of malic acid or H₂SO₄ but is independent of the initial concentrations of NaBrO₃. The experimental results indicate that acrylonitrile, H₂O₂, vitamin C, glucose or CCl₄ present in the system can inhibit the oscillations. A tentative mechanism is proposed.     

Syntheses of Key Monomers for Advanced Polymer Materials Using Cyclodextrin as Catalyst

Terephthalic acid was synthesized by the carboxylation of benzoic acid with carbon tetrachloride in aqueous sodium hydroxide solution in the presence of cyclodextrin (CyD) and copper powder as catalyst. By the use of β-CyD at the initial molar ratio to benzoic acid of 0.5, the carboxylation at 60 °C for 7 hours produced terephthalic acid in 75 mol% yield with 87% selectivity. The selective synthesis of 4,4'-biphenyldicarboxylic acid in 70 mol% yield was achieved by the carboxylation of 4-biphenylcarboxylic acid with carbon tetrachloride in the presence of β-Cyd under similar conditions. The carboxylation of 2-naphthalene carboxylic acid with carbon tetrachloride using β-Cyd under similar conditions produced 2,6-naphthalenedicarboxylic acid in 67 mol% yield with 84% selectivity. When α-CyD and γ-CyD were used in place of β-Cyd, both the yields and the selectivities of the dicarboxylic acids were markedly small. In the absence of CyD, carboxylation did not proceed. Inclusion complex formations between β-Cyd and aromatic monocarboxylic acids were indicated by the ¹H chemical shifts of the β-Cyd. The reaction mechanism was discussed on the basis of inclusion complex formation.     

Syntheses and Structures of Three Novel 1-D Lanthanide-isonicotinate Coordination Polymers

1 INTRODUCTION In the past decade or so far, the construction of extended multidimensional coordination polymers comprised of metal ions as nodes and bridged ligand as linkers or spacers of self-assembly has attracted considerable attention in supramolecular and materi- als chemistry due to the formation of the intriguing topological structures and potential applications as functional materials[1～4]. In construction of these ex- tended structures, selection of the polydentate orga- nic li…