Al2O3·3H2O阻燃环氧树脂机理探讨

采用氧指数测定法与热重法研究了Al2O3·3H2O对环氧树脂固化物的阻燃效果与机理.结果表明,Al2O3·3H2O在热分解方面与树脂固化物有阻燃匹配性,并能以零级反应快速失去2个结晶水分子,失水后形成的活性氧化铝促进了树脂固化物热解时转化成难燃物的能力,具有较高的阻燃效果.     

HCl-NaCl-C3H8O3-H2O体系溶液热力学性质

在恒定丙三醇质量分数x=0．1的条件下，测定了无液接电池（A）和电池（B）的电动势根据电池（A）电动势确定了丙三醇和水混合溶剂中的Ag－AgCl电极的标准电极电势，讨论了HCl的迁移性质；由电池（B）测得的电动势计算了HCl在该体系中的活度系数γA，计算的结果表明，对于所讨论的体系，在溶液中总离子强度保持恒定，HCl的活度系数服从Harned规则．在溶液组成恒定时，IgγA是温度倒数1／T的线性函数，讨论了混合物中HCl的相对偏摩尔焓及介质效应．     

Structure of (C3H5NH3)2H2P2O7·H2O

The bis(cyclopropylammonium)dihydrogenodiphosphate monohydrate is a new diphosphate associated with the organic molecule C₃H₅NH₂. We report the chemical preparation and the crystal structure of this organic cation diphosphate. (C₃H₅NH₃)₂H₂P₂O₇.H₂O is orthorhombic (S.G. : P2₁2₁2₁), with Z = 4 and the following unit-cell parameters : a = 4.828(1) Å, b = 11.011(1) Å, c = 25.645(2) Å. The P₂O₇ groups and H₂O water molecules form a succession of bidimensional layers perpendicular to the c axis. The organic cations ensure the three-dimensional cohesion by NH-O hydrogen bonds.     

Synthesis and Crystal Structure of （H3O）2[Cu3Cl3（H2O）3（NC9H12.5O6）2]

1 INTRODUCTION The polydentate ligand nitrilotripropionic acid, H3ntp[N(CH2CH2COOH)3], has attracted conside- rable research interest in constructing coordination polymers, designing organic-inorganic hybrid mate- rials[1], synthesizing supramolecular compounds[2], etc. due to its high degree of flexibility with three carboxylic acid moieties allowing for a variety of coordination through oxygen atoms[3]. It also pro- vides other versatile properties such as the possibili- ty of inter-…     

Thermodynamic properties of two zinc borates: 3ZnO·3B2O3·3.5H2O and 6ZnO·5B2O3·3H2O

Two pure zinc borates with microporous structure 3ZnO·3B₂O₃·3.5H₂O and 6ZnO·5B₂O₃·3H₂O have been synthesized and characterized by XRD, FT-IR, TG techniques and chemical analysis. The molar enthalpies of solution of 3ZnO·3B₂O₃·3.5H₂O(s) and 6ZnO·5B₂O₃·3H₂O(s) in 1 mol · dm⁻³ HCl(aq) were measured by microcalorimeter at T = 298.15 K, respectively. The molar enthalpies of solution of ZnO(s) in the mixture solvent of 2.00 cm³ of 1 mol · dm⁻³ HCl(aq) in which 5.30 mg of H₃BO₃ were added were also measured. With the incorporation of the previously determined enthalpy of solution of H₃BO₃(s) in 1 mol · dm⁻³ HCl(aq), together with the use of the standard molar enthalpies of formation for ZnO(s), H₃BO₃(s), and H₂O(l), the standard molar enthalpies of formation of −(6115.3 ± 5.0) kJ · mol⁻¹ for 3ZnO·3B₂O₃·3.5H₂O and −(9606.6 ± 8.5) kJ · mol⁻¹ for 6ZnO·5B₂O₃·3H₂O at T = 298.15 K were obtained on the basis of the appropriate thermochemical cycles.     

Syntheses and Crystal Structures of (H3O)(C3H5N2)[Mn(OH)6 Mo6O18]·3.5H2O and (H3O)3[Co(OH)6Mo6O18]·7H2O

The crystals of the title compounds (H3O)(C3H5N2)[Mn(OH)6Mo6O18]·3.5H2O 1 and (H3O)3[Co(OH)6Mo6O18]·7H2O 2 have been prepared and structurally determined by X-ray single-crystal diffraction. Compound 1 crystallizes in monoclinic, space group C2/c with a = 21.5018(9), b = 10.9331(5), c = 11.8667(5)A,β = 95.3570(10)o, V = 2777.5(2)A3, Z = 4, Dc = 2.802 g/cm3, Mr = 1171.80,μ(MoKα) = 3.173 mm-1, F(000) = 223, the final R = 0.0458 and wR = 0.1041 for 2093 observed reflections (I>2σ(I)); Compound 2 crystallizes in monoclinic, space group P21/c with a = 11.4042(12), b = 10.9481(11), c = 11.6722(12)A, β= 99.948(2)o, V = 1435.4(3)A3, Z = 2, Dc = 2.794 g/cm3, Mr = 1207.80,μ(MoKα) = 3.223 mm-1, F(000) = 1160, the final R = 0.0544 and wR = 0.1066 for 1906 observed reflections (I > 2σ(I)). Both compounds 1 and 2 adopt the Anderson structure, in which the anion is of centrosymmetry and formed by six octahedral edge-sharing MoO6 units surrounding the central MO6 (M = Mn or Co) octahedron.     

Two binuclear complexes containing the enrofloxacinate anion: Cd2(C19H21N3O3F)4(H2O)2 · 4H2O and Pb2(C19H21N3O3F)4 · 4H2O

The syntheses and crystal structures of the closely related but non-isostructural Cd₂(C₁₉H₂₁N₃O₃F)₄(H₂O)₂?·?4H₂O (1) and Pb₂(C₁₉H₂₁N₃O₃F)₄?·?4H₂O (2) are described, where C₁₉H₂₁N₃O₃F^? is enrofloxacinate (enro). Both compounds contain centrosymmetric, binuclear, neutral complexes incorporating a central diamond-shaped M₂O₂ (M?=?Cd, Pb) structural unit. The Cd²⁺ coordination polyhedron in 1 is a CdO₆ trigonal prism, including one coordinated water. The Pb²⁺ coordination polyhedron in 2 can be described as a very distorted square-based PbO₅ pyramid, although two additional short Pb?···?O (<3.1?Å) contacts are also present. In the crystal of the cadmium complex, O–H?···?O hydrogen bonds lead to a layered structure. In the lead compound, O–H?···?O and O–H?···?N interactions lead to chains in the crystal. Crystal data: 1: C₇₆H₉₆Cd₂F₄N₁₂O₁₈, M _r?=?1766.45, triclinic, P 1, a?=?12.185(2)?Å, b?=?12.306(3)?Å, c?=?14.826(3)?Å, α?=?68.15(3)°, β?=?70.28(3)°, γ?=?86.11(3)°, V?=?1938.2(7)?ų, Z?=?1, T?=?298 K, R(F)?=?0.030, wR(F ²)?=?0.079. 2: C₇₆H₈₈F₄N₁₂O₁₆Pb₂, M _r?=?1920.00, triclinic, P 1, a?=?12.0283(4)?Å, b?=?12.7465(4)?Å, c?=?13.0585(4)?Å, α?=?83.751(1)°, β?=?74.635(1)°, γ?=?81.502(1)°, V?=?1904.3(1)?ų, Z?=?1, T?=?298?K, R(F)?=?0.021, wR(F ²)?=?0.049.     

Synthesis and Characterization of a New Cyclotriphosphate [C8H 11 NH 3 ] 3 P 3 O 9 ·3H 2 O

Among the various categories of phosphates, the number of organic cation cyclotriphosphates remains limited. In this work, we report the chemical preparation, crystal structure, thermal analysis, and spectroscopic investigations of a new cyclotriphosphate [C₈H₁₁NH₃]₃P₃O₉·3H₂O. It is characterized by X-ray diffraction, infrared spectroscopy, nuclear magnetic resonance, and thermal analysis. This compound is a triclinic P unit cell with the following parameters: a = 13.949(4), b = 9.867(3), c = 14.180(2) Å, α = 92.22(2), β = 119.27(2), γ = 85.10(10)°, V = 1696.1(8) Å ³ , and Z = 2. Its structure has been determined and refined to R = 0.041 and R_w = 0.062, using 4527 independent reflections. The atomic arrangement can be described by corrugated thick layers built by [P₃O₉]^3- anions, ammonium groups, and water molecules. The organic entities are located between these layers. H-bonds connecting the different species play an important role in the tridimensionnal network cohesion. This compound is also characterized by infrared spectroscopy, nuclear magnetic resonance, and thermal analysis.     

H?O

光电化学分解水可将太阳能转换为绿色的氢能,为目前的能源危机和环境问题提供了一种理想的解决方案.在分解水反应中,涉及四空穴过程的产氧半反应是制约性能的关键步骤,往往需要在半导体表面沉积电催化剂以加速产氧反应动力学.因此,全面理解电催化剂在光电化学分解水体系中的作用至关重要.在目前的产氧电催化剂中,过渡金属羟基氧化物电催化剂(MOOH, M=Fe, Co, Ni)因其环保、廉价、高效以及稳定的特性,已被广泛用于半导体光阳极分解水器件中.而且, MOOH可用简单的电沉积方法沉积在光电极表面,易于大面积制备.然而,电沉积法制备的MOOH具有复杂的结构,对其作用机制的全面理解更加困难.因此,本文以电沉积MOOH修饰的硅基光阳极(n+p-Si/SiOx/Fe/FeOx/MOOH)作为模型,研究了不同电催化剂对硅光阳极光电化学产氧性能的影响.实验发现电催化剂的界面优化在电催化剂修饰的光电极中发挥着重要作用,这是因为优化的界面可以提升界面电荷传输,提供更多的催化反应活性位点以及更高的本征催化活性,从而更有利于光解水性能的提升.该项研究揭示了电催化剂在光解水器件中的作用,并为今后高效光解水器件的设计提供了一定指导.首先在多晶n+p-Si基底上热蒸镀了一层30 nm的金属Fe膜,并通过电化学活化将Fe膜表面转换为FeOx得到Fe/FeOx (记作a Fe)界面层,然后利用电沉积方法制备MOOH表面修饰层,最终得到n+p-Si/SiOx/a Fe:MOOH光阳极.X射线光电子能谱、拉曼光谱以及扫描电子显微镜表面元素成像的表征结果均证实电极表面由于界面层金属Fe元素的掺杂而形成了Fe1-xNixOOH.在模拟太阳光下用于光解水产氧时, n+p-Si/SiOx/aFe:NiOOH电极的起始电位为～1.01 VRHE (相对于可逆氢电极的电势),在1.23 VRHE下的光电流为38.82 mAcm–2,显著优于n+p-Si/SiOx/aFe、 n+p-Si/SiOx/aFe:FeOOH以及n+p-Si/SiOx/aFe:CoOOH三个对比样品,且其稳定性达到75 h.另外,我们发现n+p-Si/SiOx/aFe:MOOH电极的光电化学产氧性能均显著高于n+p-Si/SiOx/aFe电极,且p++-Si/SiOx/aFe:MOOH的电催化产氧性能也高于p++-Si/SiOx/MOOH,不仅证明了aFe界面层对Si与MOOH层之间的界面接触作用的有效调控,而且表明双电催化剂体系(aFe:MOOH)的电催化产氧活性高于单电催化剂(MOOH).热力学分析表明, n+p-Si/SiOx/a Fe:MOOH光阳极的光电压大小与其光解水产氧性能并不一致,从而排除了热力学因素对性能的关键影响.进一步从塔菲尔斜率、电化学活性表面积和电化学阻抗谱对各电极的动力学进行了分析,证明了动力学因素在上述光阳极产氧性能中的主导作用.同时发现,由于a Fe:NiOOH双电催化剂具有更高的本征电催化产氧性能,提供了更多的表面活性位点以及更有效地促进了光生载流子的传输,对动力学的提升效果更显著,从而使n+p-Si/SiOx/aFe:NiOOH光阳极表现出最高的光解水产氧性能.     

The Crystal Structures of Two Hydro-closo-Borates with Divalent Tin in Comparison: Sn(H2O)3[B10H10] · 3 H2O and Sn(H2O)3[B12H12] · 4 H2O

Journal of Cluster Science - Single crystals of Sn(H2O)3[B10H10]?·?3 H2O and Sn(H2O)3[B12H12]?·?4 H2O are easily accessible by reactions of aqueous solutions of...     

H3+O和H3+O(H2O)n(n=1,2,3)阳离子振动力场和光谱频率的理论计算

本文利用多原子分子振动力场的模型势函法对H₃⁺O和H₃⁺O(H₂O)_n(n=1～3)阳离子的振动力场作了理论计算,并对其光谱频率进行了预测.H₃⁺O和H₉⁺O₄的振动频率的结果优于从头算梯度法的结果.本文首次给出了H₅⁺O₂、H₇⁺O₃伸缩振动频率的理论预测值.     

Synthesis and structure of [Cr3O(CH3COO)6(H2O)3][UO2 (CH3COO)3] · 3H2O

Crystals of [Cr₃O(CH₃COO)₆(H₂O)₃][UO₂(CH₃COO)₃]·3H₂O (I) were synthesized for the first time and studied by X-ray crystallography. The crystals of I are orthorhombic: a = 8.3561(3) ?, b = 16.8421(5) ?, c = 25.7448(9) ?, V = 3623.2(2) ?³, space group P2₁2₁2₁, Z = 4, R = 0.0409. The structure is composed of trinuclear [Cr₃O(CH₃COO)₆(H₂O)₃]⁺ complexes and mononuclear [UO₂(CH₃COO)₃]^? complexes classified with crystal-chemical groups A₃M³B ₆ ² M ₃ ¹ (A = Cr³⁺, M³ = O^2?, B² = CH₃COO^?, M¹ = H₂O) and AB ₃ ⁰¹ (A = UO ₂ ²⁺ , B⁰¹ = CH₃COO^?), respectively. The complexes are bound to each other by electrostatic interactions and hydrogen bonds involving outer-sphere water molecules. The results of IR spectroscopic study of I are in good agreement with the structural data for the crystal.     

Two Light-Metal Dihydrogenisocyanurate Hydrates Linked by Diagonal Relationship: Syntheses,Crystal Structures,and Vibrational Spectra of Li[H2N3C3O3]·1.75 H2O and Mg[H2N3C3O3]2·8 H2O

Single-crystalline materials of Li[H₂N₃C₃O₃] · 1.75 H₂O and Mg[H₂N₃C₃O₃]₂ · 8 H₂O were obtained by dissolving stoichiometric amounts of the respective carbonates with cyanuric acid in boiling water followed by gentle evaporation of excess water after cooling to room temperature. Even though both of these compounds crystallize in the triclinic space group P1 according to X-ray structure analyses of their colorless and transparent single crystals, they adopt two new different structure types. Li[H₂N₃C₃O₃] · 1.75 H₂O exhibits the unit-cell parameters a = 884.71(6) pm, b = 905.12(7) pm, c = 964.38(7) pm, α = 67.847(2)°, β = 62.904(2)° and γ = 68.565(2)° (Z = 4), whereas the lattice parameters for Mg[H₂N₃C₃O₃]₂ · 8 H₂O are a = 691.95(5) pm, b = 1055.06(8) pm, c = 1183.87(9) pm, α = 85.652(2)°, β = 83.439(2)° and γ = 79.814(2)° (Z = 2). In both cases, the singly deprotonated isocyanuric acid forms monovalent anions consisting of cyclic [H₂N₃C₃O₃]^– units, which are arranged in ribbons typical for most hitherto known monobasic isocyanurate hydrates. The structures are governed by the oxophilic strength of the respective cation which means that they fulfil their oxophilic coordination requirements either solely with water molecules ([Mg(OH₂)₆]²⁺ for Mg²⁺) or with crystal water and one or two direct coordinative contacts to carbonyl oxygen atoms (O_(cy)) of [H₂N₃C₃O₃]^– anions ([(Li(OH₂)_2–3(O_(cy)1–2]⁺ for Li⁺). In both structures occur dominant hydrogen bonds N–H ··· O within the anionic [H₂N₃C₃O₃]^– ribbons as well as hydrogen bonds O–H ··· O between these ribbons and the hydrated Li⁺ and Mg²⁺ cations.     

Rate constants of atomic hydrogen formation in H3O+(H2O) n + e → H + (H2O) n gas-phase processes

Using the Maxwellian electron velocity distribution and the Breit-Wigner approximation of the reaction cross section, the kinetic parameters of the hydrogen atom formation upon the electron capture by positively charged hydronium-water clusters are estimated. Calculations of the cross sections and rate constants are based on the data of quantum chemical studies of H₃O⁺(H₂O) _n and H₃O(H₂O) _n clusters, particularly on the detailed analysis of the spacing of high-lying states of the radicals and the character of the unpaired electron density distribution, as well as on the general trend in the electron affinity change of the cations depending on the number of water molecules. The lifetimes of the radicals before the dissociation are taken from the classical nonempirical molecular dynamics runs. The results are compared to available experimental data. The article is published in the original.     

Dimethylformamide as a convenient CO source for the facile preparation of rhodium-, iridium- or ruthenium-chlorocarbonyl complexes directly from RhCl3·3H2O,IrCl3·3H2O or RuCl3·3H2O

The anionic complexes [RhCl₂(CO)₂]⁻, [IrCl₂(CO)₂]⁻ or [RuCl₃(CO)₂(DMF)]⁻ can be obtained in high yields (up to 85 %) and in less than 60 min by refluxing dimethylformamide solutions of RhCl₃·3H₂O, IrCl₃·3H₂O or RuCl₃·3H₂O. Depending on the metal, the presence of small amounts of water and/or hydro- chloric acid greatly accelerates the reduction step. For rhodium, several intermediates have been trapped which allow us to propose a mechanism for this reaction.     

Crystal structures of Co3(SeO3)3·H2O and Ni3(SeO3)3·H2O,two new isotypic compounds

Summary The crystal structures of the new, hydrothermally synthesized, isotypic compounds Co₃(SeO₃)₃·H₂O and Ni₃(SeO₃)₃·H₂O were determined by direct and Fourier methods and refined toR _w=0.023, 0.032 using single crystal X-ray data up to sin/=0.81 Å^–1 [space group P ,a=8.102 (2), 7.986 (3) Å;b=8.219 (2), 8.133 (3) Å;c=8.572 (2), 8.422 (3) Å, =69.15 (1), 69.50 (1)°; =62.88 (1), 62.50 (1)°; =67.23 (1), 67.64 (1)°;Z=2]. The structures are built up from [Me ₅(SeO₃)₆·2H₂O]^2– sheets containing three crystallographically different types of octahedrally coordinatedMe ²⁺ and trigonal pyramidal coordinated Se⁴⁺ atoms, respectively. These sheets are linked only by a fourth type ofMe ^2+[6] atom. All coordination polyhedra deviate significantly from their ideal shapes, bond lengths within the extremly distortedMe(4)O₆ polyhedra range from 1.983 (2) Å to 2.403 (2) Å in Co₃(SeO₃)₃·H₂O and from 1.987 (4) Å to 2.301 (3) Å in the Ni compound, O-Se-O bond angles were found between 92.8 (2)° and 104.9 (1)°. Hydrogen bond lengths are 2.802 (3)Å and 2.600 (4)Å in the Co compound, and 2.762 (6) Å and 2.561 (6) Å in Ni₃(SeO₃)₃·H₂O. The latter is one of the shortest known hydrogen bonds donated by a water molecule.

---

Die Kristallstrukturen von Co₃(SeO₃)₃·H₂O und Ni₃(SeO₃)₃·H₂O, zwei neue isotype Verbindungen

Zusammenfassung Die Kristallstrukturen der neuen, hydrothermal synthetisierten, isotypen Verbindungen Co₃(SeO₃)₃·H₂O und Ni₃(SeO₃)₃·H₂O wurden mit direkten und Fourier-Methoden bestimmt und unter Verwendung von Einkristallröntgendaten bis sin/=0.81 Å^–1 aufR _w-Werte von 0.023, 0.032 verfeinert [Raumgruppe P ,a=8.102 (2), 7.986 (3) Å;b=8.219 (2), 8.133 (3) Å;c=8.572 (2), 8.422 (3) Å, =69.15 (1), 69.50 (1)°; =62.88 (1), 62.50 (1)°; =67.23 (1), 67.64 (1)°;Z=2]. Die Strukturen werden von [Me ₅(SeO₃)₆·2H₂O]^2– Schichten aufgebaut, die je drei kristallographisch unterschiedliche Arten von oktaedrisch koordiniertenMe ²⁺ und trigonal pyramidal koordinierten Se⁴⁺ Atomen enthalten. Diese Schichten sind nur durch eine vierte Art vonMe ^2+[6] Atomen verknüpft. Alle Koordinationspolyeder weichen deutlich von ihren Idealformen ab, Bindungslängen in den extrem verzerrtenMe(4)O₆ Polyedern variieren zwischen 1.983 (2) Å und 2.403 (2) Å in Co₃(SeO₃)₃·H₂O und zwischen 1.987 (4) Å und 2.301 (3) Å in der Ni-Verbindung, O-Se-O-Bindungswinkel liegen zwischen 92.8 (2)° und 104.9 (1)°. Wasserstoffbrückenlängen sind 2.802 (3) Å und 2.600 (4) Å in der Co-Verbindung, und 2.762 (6) Å und 2.561 (6) Å in Ni₃(SeO₃)₃·H₂O. Letztere ist eine der kürzesten bekannten Wasserstoffbrücken eines Wassermoleküls.

     

A single-crystal fourier transform raman spectroscopic study of [Cr3O(OOCCH3)6(H2O)3]Cl·5H2O

Solution and single-crystal FT-Raman spectroscopy with polarization analysis have been used to assign a frequency of 147 cm⁻¹ to the totally symmetric Cr₃O stretching vibration of the complex cation in the dark coloured compound [Cr₃O(OOCCH₃)₆(H₂O)₃]Cl ·5H₂O. For this vibration, the polarizability derivatives parallel to the metal triangle are shown to be greater in magnitude than that perpendicular to the triangle.     

混合电解质中HCl热力学性质——HCl-C3H8O3-NaCl-H2O体系

活度系数;电动势;电极电势;无液接电池;混合电解质中HCl热力学性质——HCl-C3H8O3-NaCl-H2O体系