Thermal Properties of Complexes of Mn(II), Fe(II), Co(II), Ni(II) With 2,2'-bipyridine Or 4,4'-bipyridine and Thiocyanates

The compounds ML₂(NCS)₂, (M(II)=Mn, Co), FeL₂(NCS)₂×2H₂O, NiL₃ NCS)₂×3H₂O (L=2,2'-bipyridine, 2-bipy) MX₂(NCS)₂×2H₂O (M(II)=Mn, Fe; X=4,4'-bipyridine, 4-bipy) have been prepared and their IR spectra and molar conductivity studied. The thermal decomposition of the complexes was studied under non-isothermal conditions in air. During heating the hydrated complexes lose crystallization water molecules in one or two steps and then decompose via different intermediate compounds to the oxides Mn₃O₄, Fe₂O₃, CoO, NiO. This revised version was published online in August 2006 with corrections to the Cover Date.     

新颖的镧-2-氟苯甲酸及2，2′-联吡啶配合物的合成与晶体结构

2-fluorobenzoic acid (2-HFBA) and 2,2′-bipyridine (2,2′-bpy) was used as ligands to react with lanthanum to obtain a complex, [La(2-FBA)₃·(2,2′-bpy)]₂. The structure of the complex contains three independent molecules. In two of them, the two central metal ions are connected together through four 2-FBA groups by bidentate bridging and chelating-bridging two modes. In another, the two central metal ions are connected together through four bidentate bridging 2-FBA groups. CCDC: 237658.     

六氟磷酸二(2,2'-联吡啶)·(4,4'-二甲基-2,2'-联吡啶) 合钌(Ⅱ)的二维核磁共振谱分析

用一维NMR方法研究了电化学发光物质六氟磷酸二(2,2'-联吡啶)·(4,4'-二甲基-2,2'-联吡啶)合钌(Ⅱ)的立体结构,借助二维1H-1H COSY和1H-13C COSY实验技术对其氢谱和碳谱进行了完全的归属,并给出了其氢谱和碳谱的化学位移值.     

Thermal and other properties of complexes of Mn(II), Co(II) and Ni(II) with 2,2'-bipyridine and trichloroacetates

Complexes of the general formulae Mn(2-bpy)₂(CCl₃COO)₂, Co(2-bpy)₂(CCl₃COO)₂·H₂O and Ni(2-bpy)₂(CCl₃COO)₂·2H₂O (where: 2-bpy=2,2'-bipyridine) have been prepared and characterized by VIS and IR spectroscopy, conductivity and magnetic measurements. The thermal properties of complexes in the solid state were studied under non-isothermal conditions in air atmosphere. During heating the complexes decompose via different intermediate products to the oxides Mn₃O₄, CoO and NiO. A coupled TG-MS system was used to detection the principal volatile products of thermal decomposition and fragmentation processes of obtained compounds. The principal volatile products of thermal decomposition of complexes are: H₂O⁺, CO₂ ⁺, Cl₂ ⁺ and other. This revised version was published online in August 2006 with corrections to the Cover Date.     

Some dn Metal Complexes with 4,4'-bipyridine and Trichloroacetates. Preparation,characterization and thermal properties

The new mixed ligand complexes with formulae Co(4-bpy)₂L₂⋅2H₂O (I), Cu(4-bpy)₂L₂⋅H₂O (II) and Cd(4-bpy)L₂⋅H₂O (III) (4-bpy=4,4'-bipyridine, L=CCl₃COO^–) were prepared. Analysis of the IR spectra indicate that 4-bpy is coordinated with metal ions and carboxylates groups bond as bidentate chelating ligands. The electronic spectra are in accordance with pseudo-octahedral environment around the central metal ion in the Co(II) and Cu(II) complexes. The thermal decomposition of the synthesized complexes was studied in air. A coupled TG-MS system was used to analyse the principal volatile thermal decomposition products of Co(II) and Cu(II) complexes. Corresponding metal oxides were identified as a final product of pyrolysis with intermediate formation of metal chlorides. This revised version was published online in July 2006 with corrections to the Cover Date.     

Synthesis and Thermal Analysis of 2,2′-bipyridine Divalent Transition Metal Hexachloroplumbates

Several complex salts of the general formula [M(II) (bipy)_x(H₂O)_y]PbCl₆ (where x=2–3, y=0–2 and M=Mn(II), Fe(II), Ni(II), Co(II), Cu(II), Zn(II), Cd(II) and Hg(II)) were synthesized and investigated by DTA, TG and DTG. Some of the decomposition products were identified by IR spectroscopy and other methods. The compounds decompose with the liberation of water (in the case of hydrates), chlorine (sometimes causing chlorination of organic fragments), organic molecules (sometimes chlorinated) and sometimes hydrogen chloride. The residues comprise metal(II) chlorides and PbCl₂. This revised version was published online in August 2006 with corrections to the Cover Date.     

Syntheses, crystal structures and luminescent properties of two new 1D d coordination polymers constructed from 2,2′-bibenzimidazole and 1,4-benzenedicarboxylate

Two novel interesting d¹⁰ metal coordination polymers, [Zn(H₂bibzim)(BDC)]_n (1) and [Cd(H₂bibzim)(BDC)]_n (2) [H₂bibzim=2,2′-bibenzimidazole, BDC=1,4-benzenedicarboxylate] have been synthesized under solvothermal conditions and structurally characterized. Both 1 and 2 are constructed from infinite neutral zigzag-like one-dimensional (1D) chains. The π-π interactions and interchain hydrogen-bonding interactions further extend the 1D arrangement to generate a 3D supramolecular architecture for 1 and 2. Both complexes have high thermal stability and display strong blue fluorescent emissions in the solid state upon photo-excitation at 365 nm at room temperature. They are the first two examples that 2,2′-bibenzimidazole has been introduced into the d¹⁰ coordination polymeric framework.     

四溴代对苯二甲酸及2，2′-联吡啶构筑的铜配位聚合物的合成、晶体结构及热稳定性

以四溴代对苯二甲酸(H2TBTA)与2,2′-联吡啶(2,2′-bipy)为配体,与硝酸铜在水和甲醇混合溶剂中合成了1个一维铜配合物{[Cu(2,2′-bipy)(TBTA)(H2O)].H2O}n,并通过元素分析、红外分析、热重分析、X-射线粉末衍射和X-射线单晶衍射对其进行了表征。该配合物属于正交晶系,空间群为Pna21,a=1.399 9(11)nm,b=0.929 3(7)nm,c=1.557 9(11)nm,V=2.027(3)nm3,Z=4,R1=0.053 5。中心Cu(Ⅱ)离子处于一个五配位环境中,且在配合物中存在着π-π相互作用和氢键作用。热重分析表明该配合物在203℃开始发生分解。     

Crystal Structure and Thermal Property of a Binuclear Manganese(II) Sulfate Complex with Carbohydrazide

The binuclear manganese(II) complex of formula [Mn₂(CHZ)₂(H₂O)₂(SO₄)₂] (CHZ = carbohydrazide) (1) has synthesized in aqueous solution and characterized by elemental analysis, IR, and single crystal X-ray diffraction. The compound 1 crystallizes in monoclinic system, space group P2(1)/n, a = 7.083(1) Å, b = 7.985(1) Å, c = 14.045(2) Å, β = 90.46(1)^°, V = 794.42(16) ų, Z = 2, R = 0.0308 with 1481 reflections. In the title complex, two Mn(II) cations are bonded via the bridging oxygen atoms into a centrosymmetric dimeric unit. The Mn(II) dimers are further extended into layers by means of the bridging sulfate groups. Each Mn atom in the complex is in bivalent state with a distorted pentagonal bipyramid configuration and has a N₂O₅ donor set which consists of two nitrogen atoms and five oxygen atoms provided by the ligands of two CHZ molecules, one water molecule, and two sulfate ions. The CHZ tridentate ligands are coordinated with adjacent Mn(II) cation via two terminal N atoms and the carbonyl O atom and sulfate anions act as bidentate bridge ligand. Four kinds of Mn(II) CHZ complex structures are compared. The thermal property of title complex was studied by using DSC and TG-DTG techniques. The results exhibit the title complex is highly stable.     

Thermal decomposition and isomerization of 2,2'-di(benzoxazolyl) disulfide

Heating 2,2′-di(benzoxazolyl) disulfide at 140–150 °C results in its decomposition with the elimination of elemental sulfur to yield 2,2′-di(benzoxazolyl) sulfide and 3-(2-benzoxazolyl)benzoxazoline-2-thione. Plausible reaction mechanisms are discussed. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1829–1831, October, 1993.     

X-ray and Thermal Analysis of Selected Drugs Containing Acetaminophen

Studies carried out by X-ray and thermal analysis confirmed that acetaminophen (paracetamol), declared by the manufacturers as an Active Pharmaceutical Ingredient (API), was present in all studied medicinal drugs. Positions of diffraction lines (2θ angles) of the studied drugs were consistent with standards for acetaminophen, available in the ICDD PDF database Release 2008. |Δ2θ| values were lower than 0.2°, confirming the authenticity of the studied drugs. Also, the values of interplanar distances d_hkl for the examined samples were consistent with those present in the ICDD. Presence of acetaminophen crystalising in the monoclinic system (form I) was confirmed. Various line intensities for API were observed in the obtained diffraction patterns, indicating presence of the preferred orientation of the crystallites in the examined samples. Thermal analysis of the studied substances confirmed the results obtained by X-ray analysis. Drugs containing only acetaminophen as an API have melting point close to that of pure acetaminophen. It was found that presence of other active and auxiliary substances affected the shapes and positions of endothermal peaks significantly. A broadening of endothermal peaks and their shift towards lower temperatures were observed accompanying an increase in the contents of additional substances being “impurities” in relation to the API. The results obtained by a combination of the two methods, X-ray powder diffraction (XRPD) and differential scanning calorimetry/thermogravimetry (DSC/TGA), may be useful in determination of abnormalities which can occur in pharmaceutical preparations, e.g., for distinguishing original drugs and forged products, detection of the presence of a proper polymorphic form or too low content of the active substance in the investigated drug.     

Thermal Investigation of the Compounds of the Copper(II) Mono(o-hydroxybenzoate) with Chelate Ligands

Heteroligand complexes of copper(II) were obtained as a result of the reaction of Cu(II) mono (o-hydroxybenzoate) (monohydrate) with 8-hydroxyquinoline (HOx), o-aminophenol (NH₂Ph) and 2,2′-dipyridyl (2,2′-dipy). The mixture of the mono compound with: Cu(II) di(o-aminobenzoate) or Cu(II) di(o-hydroxybenzaldoximate) were obtained by the reaction with o-aminobenzoic acid (H₂A) and o-hydroxybenzaldoxime (H₂Salox). The obtained compounds and their sinters were subjected to chemical, X-ray and thermal analyses. This revised version was published online in July 2006 with corrections to the Cover Date.     

Synthesis, Crystal Structure and Thermal Property of a Manganese(II) 4-Carboxyphenoxyacetate Complex

1 INTRODUCTION Organic aromatic carboxylic acids which com-monly possess multiple coordination modes are ex-cellent candidates for constructing supramolecularmetal complexes[1～6]. 4-Carboxyphenoxyacetic acid(4-CPOAH2), widely used in biological activitystudies, is a multidentate flexible ligand that not onlyhas versatile binding possibilities but also can formregular hydrogen bonds as both hydrogen-bond donorand acceptor. However, there have been few reportson the coordination chemistr…     

Thermal Analysis of Cobalt(II) Salts with some Carboxylic Acids

The thermal analysis of CoC₂O₄·2H₂O, Co(HCOO)₂·2H₂O and Co(CH₃COO)₂·4H₂O was carried out with simultaneous TG-DTG-DTA measurements under non-isothermal conditions in air and argon atmospheres. The intermediates and the end products of decomposition were characterised by X-ray diffraction and IR and UV-VIS spectroscopy. The decomposition of the studied compounds occur in several stages. The first stage of dissociation of each compound is dehydration both in air and argon. The next stages differ in air and argon. The final product of the decomposition of each compound in air is Co₃O₄. In argon it is a mixture of Co and CoO for cobalt(II) oxalate and cobalt(II) formate but CoO for cobalt(II) acetate. This revised version was published online in August 2006 with corrections to the Cover Date.     

Selective Transport of Lead(II) and Strontium(II) Through a Crown Ether-Based Polymer Inclusion Membrane Containing Dialkylnaphthalenesulfonic Acid

New polymer inclusion membranes (PIMs) containing 18-membered crownethers and dialkylnaphthalenesulfonic acid are proposed for Sr2+ and Pb2+removal from nitric acid solutions. The influence of source phasecomposition and stripping agents was characterized and permeabilitycoefficients were calculated. The PIMs are easy to prepare and may be usefulin separation and concentration procedures for these cations from complexmixtures such as nuclear waste. Long-term stability was obtained for atleast several weeks of constant use during which no significant change ofpermeability was observed.     

Crystal Structure, Thermal Analysis and Theoretical Calculation of a One-dimensional Chain Complex [Zn（dafo）2（H2O）2]（NO3）2

Introduction Molecular recognition and molecular self-assemblycarried out by cooperation of the weak interactions(electrostatic reaction, hydrogen bonds, van der Waalsforce, short-range repulsive force, etc) are the commonphenomena in nature. In recent years, the research onsupramolecular complex has been a crossing focus ofseveral subjects such as chemistry, physics, biology,material and information.1 Supramolecular complex hasa wide application foreground in material, catalysis,conductor,…     

Synthesis, Crystal Structure and Thermal Stability of (Diacetylacetone)(diimidazole)Nickel(II) Complex

1 INTRODUCTION Acetylacetone is well known as the intermediate product of organic synthesis reaction, which can be used as annexing agent in gasoline, lubricant and desiccant in paint. Also it has been found to possess fungicidal and insecticidal activi…     

1, 3-双(2-(2,2-二氰乙烯基)苯氧基)-2-丙醇及其银(Ⅰ)配合物的合成、晶体结构及其荧光性质

用1,3-双(2-甲酰基苯氧基)-2-丙醇和丙二腈进行反应得到1,3-双(2-(2,2-二氰乙烯基)苯氧基)-2-丙醇配体L,然后将配体与Ag Sb F6进行配位反应,得到配合物[Ag LSb F6]n·n CHCl3(1),并用元素分析,FTIR和X-射线单晶衍射进行了表征。结果表明,配体L属于单斜晶系,空间群P21/n,晶体学参数:a=0.990 2(11)nm,b=2.181(2)nm,c=1.012 2(11)nm,β=109.374(10)°,V=2.062(4)nm3,Z=4,Dc=1.277 g·cm-3,Mr=396.40,μ=0.087 mm-1,F(000)=824,R1=0.064 2,w R2=0.117 4(I>2σ(I))。配合物1属于单斜晶系,空间群P21/n,晶体学参数:a=1.270 57(11)nm,b=1.456 44(13)nm,c=1.669 85(14)nm,β=105.643(3)°,V=2.975 6(4)nm 3,Z=4,Dc=1.918 g·cm-3,Mr=859.39,μ=1.907 mm-1,F(000)=1 664,R1=0.0417,w R2=0.1 032(I>2σ(I))。在配合物1中,配体L表现为四齿配体分别与4个银(Ⅰ)离子配位,同时,每一个银(Ⅰ)离子与4个相邻配体配位形成2D层状结构。同时,研究了配体和配合物的固体荧光性质。     

A Fluorescent Cobalt（II） Complex for the Recognition of Cations and Small Molecules： Synthesis, Structure and Characterization

A fluorescent cobalt(Ⅱ) complex, 1 [Co(H2bibim)2(5-nipa)], for the recognition of cations and small molecules constructed with 5-nitroisophthalic acid (5-H2nipa) and 2,2-biben-zimidazole(H2bibim) has been synthesized by hydrothermal methods and structurally characterized by elemental analysis, IR spectroscopy, PL and single-crystal X-ray diffraction. The cobalt units are six-coordinated by two H2bibim ligands and one 5-nitroisophthalic acid group, which are further connected into a three-dimensional (3D) network by intermolecular hydrogen bonds. Complex 1 exhibits fluorescence and thus has detection capabilities for different cations and small solvent molecules in the solution state at room temperature.