Synthesis and Crystal Structure of a Novel Polymeric Thiocyanato-Bridged Heteronuclear Complex of Copper(II) and Cadmium(II)

The title polymeric complex of Cu(II) and Cd(II) bridged by thiocyanate, Cu(en)₂[Cd(SCN)₃]₂, has been prepared and its structure determined by X-ray diffraction (XRD) methods. The crystal structure reveals that the Cu(II) atom is in an elongated octahedral coordination formed by two SCN^– anions and two en molecules. The Cd(II) atom is in a distorted octahedral coordination formed by six bridging SCN^– anions. Two different bridging thiocyanate anions exist in the complex. Both 1,1--SCN^– and 1,3--SCN^– anion act a role of bridge ligand and link Cu(II), Cd(II) atoms, and adjacent Cd(II). Cd(II) atoms form the three-dimensional (3-D) network polymeric structure. The IR and UV-Vis spectra have also been investigated.     

具有可逆热致变色有机-无机杂化铜化合物的合成及表征

在浓盐酸水溶液中，碘化N，N-二甲基-1，5-二氮杂环[3.2.1]辛烷（[3.2.1-Me₂dabco]I₂）和碘化1-氨基-1，4-二氮杂环[2.2.2]辛烷（[2.2.2-NH₂dabco]I）与氯化铜反应得到2种有机-无机杂化铜化合物[3.2.1-Me₂dabco][CuCl₄]（1）和[2.2.2-NH₂dabco][CuCl₄]（2）。X射线单晶结构衍射证实化合物1和2中的无机阴离子是[CuCl₄]^2-四面体。化合物1和2表现出可逆的热致变色现象，随着温度升高，它们的颜色从黄色变为红色，这应该是由[CuCl₄]^2-四面体的变形引起的。     

Crystal structures of 6-[(2-hydroxy-1,1-bis-hydroxymethyl-ethylamino)-methylene]-4-nitro-cyclohexa-2,4-dienone hydrate and 6-[(2-hydroxy-1,1-bis-hydroxymethyl-ethylamino)-methylene]-4-bromo-cyclohexa-2,4-dienone

Crystal structures of 6-[(2-hydroxy-1,1-bis-hydroxymethyl-ethylamino)-methylene]-4-nitro-cyclohexa-2,4-dienone hydrate (I) and 6-[(2-hydroxy-1,1-bis-hydroxymethyl-ethylamino)-methylene]-4-bromo-cyclohexa-2,4-dienone (II) have been determined. The crystals of I are monoclinic, a = 16.957(1) Å, b = 10.729(2) Å, c = 7.240(3) Å; β = 99.56(3)°, space group P2₁/c, Z = 4, R = 0.0492. The crystals of II are triclinic, a = 10.282(2) Å, b = 7.189(3) Å, c = 16.831(3) Å; α = 90.67(3)°, β = 100.10(3)°, γ = 95.87(3)°; space group P-1, Z = 4, R = 0.0591. The independent part of the unit cell of I contains one unique molecule and water of crystallization, while in II — two unique molecules A and B. C(CH₂OH)₃ fragment of the molecule B manifests the disordering of alcohol oxygen atoms. Both in I and II, the salicylidene fragment of the molecules exists in the quinoid tautomeric form.     

Crystallization and melting of polyethylene copolymers: Differential scanning calorimetry and atomic force microscopy studies

The Hoffman–Lauritzen theory of secondary, surface nucleation and growth was primarily relied upon for about 40 years after its introduction in about 1960 to rationalize the crystallization of flexible chain polymers into lamellar crystals. However, in about 1998, Strobl and coworkers introduced a different model for crystallization, based on the stage‐wise formation of lamellae. Two major components of this model were as follows: (1) the concept of the formation of a mesomorphic melt as a precursor to crystallization and (2) the control of the melting temperature range of lamellar crystals of homogeneous polyolefin copolymers by an inner degree of order or perfection rather than on the crystal thickness. The first concept is in disagreement with the HL theory and the second with the Gibbs‐Thomson theory, which associates melting temperature with lamella thickness. In the present study, differential scanning calorimetry and atomic force microscopy were successfully employed to monitor the in situ quiescent crystallization of polyethylene homopolymer and copolymer. In the present study, evidence was not found to support the concept of lamellae with equal thickness melting over a broad temperature range. Some evidence was found that might be interpreted to support the concept of a mesomorphic melt as a precursor to crystallization. At present, the model promoted by Strobl and coworkers appears to be at an uncertain stage at which strong proof or disproof are not available. However, this alternative model has injected a new vitality into the study of crystallization of flexible chain polymers. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 2369–2388, 2006     

One and Two-dimensional Structures of a New Oxamido Copper(II) Complex with Phthalato Bridged

1 INTRODUCTION Coordination polymers are a family of materials composed of 1D chains, 2D sheets, and 3D networks of metal-organic building blocks connected via co- valent and hydrogen bonds. Recently, they have re- ceived increasing attention for their fascinating struc- tures and topological features[1～4]. The complex as ligands approach is one of the best strategies to de- sign and synthesize polynuclear species, and a good example of ‘complex ligand’ is represented by mono- nuclear…     

Synthesis, characterization and thermal properties of small R2R2NX-type quaternary ammonium halides

Twenty-one R₂R^′₂N⁺X⁻ -type (R=methyl or ethyl, R^′=alkyl, X=Br or I) quaternary ammonium (QA) halides have been prepared by using a novel one-pot synthetic route in which a formamide (dimethyl-, diethylformamide, etc.) is treated with alkyl halide in the presence of sodium or potassium carbonate. The formation of QA halides was verified with ¹H-NMR, ¹³C-NMR, MS and elemental analysis. The crystal structures of four QA halides (two bromide and two iodide) were determined using X-ray single crystal diffraction, and the powder diffraction method was used to study the structural similarities between the single crystal and microcrystalline bulk material. The thermal properties of all compounds were studied using TG/DTA and DSC methods. The smallest compounds decomposed during or before melting. The decreasing trend of melting points was observed when the alkyl chain length was increased. The liquid ranges of 120-180 °C were observed for compounds with 5-6 carbon atoms in the alkyl chain. The low melting points and wide liquid ranges suggest potential applicability of these compounds for example as ionic liquids precursors.     

Synthesis and characterization of novel epoxy monomers and liquid crystal thermosets

Four new epoxy monomers have been synthesized and characterized as part of a program to prepare novel liquid crystal thermoset (LCT) materials. Three of the new epoxy monomers contained a biphenyl mesogen and were not liquid crystalline (LC). The remaining epoxy monomer, which contained a 1,4-dibenzoyloxybenzene mesogen, was synthesized in an overall yield of 30% and displayed a broad (83°C) nematic liquid crystalline phase. The new liquid crystalline epoxy monomer was cured at 120°C and postcured at 175°C with a stoichiometric amount of 1,4-phenylenediamine. The thermal transitions of the resulting LCT were studied by differential scanning calorimetry (DSC), polarized light optical microscopy (POM), thermomechanical analysis (TMA), and wide angle x-ray diffraction (WAXD) as a function of cure time and temperature. A process characterization diagram was constructed which shows that LCTs based on this new LC monomer can be processed in the liquid crystalline phase over a broad range of times and temperatures. Qualitative agreement with previous epoxy LCT results was found, as LCT's with smectic phases and without clearing temperatures were observed at long cure times (high crosslink densities), whereas nematic phases with clearing temperatures predominated in networks at short cure times (low crosslink densities). © 1993 John Wiley & Sons, Inc.     

Synthesis and Crystal Structure of Diaquabis{2,4-dibromo-6-[(2-ethylaminoethylimino)methyl]-phenolato}nickel(Ⅱ) Dinitrate Diacetonitrile

The title mononuclear Schiff base nickel(Ⅱ) complex [Ni(C11H14Br2N2O)2(H2O)2]· 2NO3·2C2H3N was prepared and characterized by elemental analysis,IR spectrum,and single-crystal X-ray diffraction. The crystal belongs to the monoclinic system,space group P21/n with a=15.534(2),b=7.647(1),c=16.435(2),β=103.252(2)o,V=1900.3(4)3,Z=2,Dc=1.750 g/cm3,Mr=1000.99,λ(MoKα)=0.71073,μ=4.776 mm-1,F(000)=996,the final R=0.0368 and wR=0.0724. A total of 3988 unique reflections were collected,of which 2764 with I > 2σ(I) were observed. The complex consists of a mononuclear [Ni(C11H14Br2N2O)2(H2O)2]2+ cation,two nitrate anions and two acetonitrile molecules. The Ni atom,lying on the inversion centre,is six-coordinated by two Schiff bases and two water molecules to assume an octahedral coordination geometry. The molecules in the crystal are linked through intermolecular hydrogen bonds of N–H…O,N–H…Br,O–H…O,O–H…N and C–H…O to form layers.     

含非交换氘的四唑-锌配合物

The solvothermal reaction (D₂O) of 2,6-dideuterium-4-cyanopyridine with ZnCl₂ in the presence of NaN₃ offers a novel complex Zn(OD)(C₆H₂D₂N₄) (1) in which Zn has a distorted tetrahedron composed of two N atoms from one tetrazoyl group and pyridyl group and two O atoms from two deuteratohydroxy OD groups. Crystal data for 1: Pbcn, a=1.456 8(5) nm, b=0.659 2(2) nm, c=1.645 3(5) nm, α=90°, β=90°, γ=90°, V=1.580 0(9) nm³, Z=8, M=231.54, D_c=2.236 Mg·m^-3, μ=3.070 mm^-1, R₁=0.043 4, wR₂=0.120 6, S=1.029. CCDC: 660629.     

Die Perthioborate RbBS3, TIBS3 und TI3B3S10

The Perthioborates RbBS₃, TIBS₃, and Tl₃B₃S₁₀ . RbBS₃ (P2₁/c, a=7.082(2) Å, b=11.863(4) Å, c=5.794(2) Å, β=106.54(2)°) was prepared as colourless, plate-shaped crystals by reaction of stoichiometric amounts of rubidium sulfide, boron, and sulfur at 600°C and subsequent annealing. TlBS₃ (P2₁/c, a=6.874(3) Å, b=11.739(3) Å, c=5.775(2) Å, β=113.08(2)°) which is isotypic with RbBS₃ was synthesized from a sample of the composition Tl₂S · 2 B₂S₃. The glassy product which was obtained after 7 h at 850°C was annealed in a two zone furnace for 400 h at 400→350°C. Yellow crystals of TlBS₃ formed at the warmer side of the furnace. Tl₃B₃S₁₀ (P1 , a=6.828(2) Å, b=7.713(2) Å, c=13.769(5) Å, α=104.32(2)°, β=94.03(3)°, γ=94.69(2)°) was prepared as yellow plates from stoichiometric amounts of thallium sulfide, boron, and sulfur at 850°C and subsequent annealing. All compounds contain tetrahedrally coordinated boron. The crystal structures consist of polymeric anion chains. In the case of RbBS₃ and TlBS₃ nonplanar five-membered B₂S₃ rings are spirocyclically connected via the boron atoms. To obtain the anionic structure of Tl₃B₃S₁₀ every third B₂S₃ ring of the polymeric chains of MBS₃ is to be substituted by a six-membered B(S₂)₂B ring.