Synthesis and single-crystal structure of lead oxide nanoclusters in zeolite Y, |Pb 15.5 2+ (Pb4O4(Pb 16/19 2+ Pb 3/19 4+ )4)4.75|[Si117Al75O384]-FAU

A single crystal of excessively Pb²⁺-exchanged zeolite Y (|Pb _15.5 ²⁺ (Pb₄O₄(Pb _16/19 ²⁺ Pb _3/19 ⁴⁺ )₄)_4.75|[Si₁₁₇Al₇₅O₃₈₄]-FAU) was prepared by exchange of Na–Y (|Na₇₅|[Si₁₁₇Al₇₅O₃₈₄]-FAU, Si/Al = 1.56) with an aqueous stream 0.05 M Pb(C₂H₃O₂)₂ at 294 K, followed by vacuum dehydration at 1 × 10^?6 Torr and 693 K. Its structure was determined at 100 K, by X-ray diffraction techniques in the cubic space group Fd $ \overline{3} $ 3 ¯ m and was refined to the final error indices R ₁/wR ₂ = 0.0639/0.1323. About 53.5 Pbⁿ⁺ ions per unit cell occupy three different equipoints; 26 are at site I′, 19 are at site II, and the remaining 8.5 are at another site II. Three Pb⁴⁺ ions at some of the positions must have higher oxidation states due to elevated dehydration temperature; Pb(IIa) is supposed to coexist with Pb²⁺ and Pb⁴⁺ ions assuming the charge balance of the zeolite framework. A distorted Pb₄O₄ cube, alternating Pb²⁺ at Pb(I′) and O^2? at O(5), coordinates with four Pb²⁺ and/or Pb⁴⁺ ions through its oxygen atoms to give a [Pb ₄ ²⁺ O ₄ ^2? (Pb _16/19 ²⁺ Pb _3/19 ⁴⁺ )₄]^176/19+ cluster in 4.75 of eight sodalite cavities per unit cell in zeolite Y.     

Synthesis and structural refinement of fully dehydrated fully Zn<Superscript>2+</Superscript>-exchanged zeolite Y (FAU), |Zn<Subscript>35.5</Subscript>|[Si<Subscript>121</Subscript>Al<Subscript>71</Subscript>O<Subscript>384</Subscript>]-FAU

The single-crystal structure of |Zn_35.5|[Si₁₂₁Al₇₁O₃₈₄]-FAU per unit cell, a = 24.794(1), dehydrated at 673 K and 1 × 10^?6 Torr, has been determined by single-crystal X-ray diffraction techniques in the space group \( Fd\bar{3}m \) at 294(1) K. The structure was refined using all intensities to the final error indices (using the 930 reflections for which F _o > 4σ(F _o)) R ₁ = 0.0448 (based on F) and wR ₂ = 0.1545 (based on F ²). About 35.5 Zn²⁺ ions per unit cell are found at an unusually large number of crystallographic distinct positions, six. The 0.5 Zn²⁺ ion per unit cell is located at the center of double 6-ring (D6R, site I; Zn(I)-O(3) = 2.642(3) Å and O(3)-Zn(I)-O(3) = 81.23(12) and 98.77(12)°). Two different site-I′ positions (in the sodalite cavities opposite D6Rs) are occupied by 14 and 3 Zn²⁺ ions per unit cell, respectively; these Zn²⁺ ions are recessed 0.67 Å and 1.02 Å, respectively, into the sodalite cavities from their 3-oxygens plane (Zn(I′a)-O(3) = 2.094(3) Å, Zn(I′b)-O(3) = 2.23(5) Å, O(3)-Zn(I′a)-O(3) = 110.32(12)°, and O(3)-Zn(I′b)-O(3) = 100.9(30)°). Site-II′ positions (in the sodalite cavities opposite S6Rs) are occupied by 6 Zn²⁺ ions, each of which extends 0.63 Å into the sodalite cavities from their 3-oxygens plane (Zn(II′)-O(2) = 2.164(3) Å and O(2)-Zn(II′)-O(2) = 112.00(12)°). Twelve Zn²⁺ ions are found at two nonequivalent sites II (in the supercage) with occupancies of 7 and 5 ions, respectively; these Zn²⁺ ions are recessed 0.52 Å and 0.96 Å, respectively, into the supercage from their 3-oxygens plane (Zn(IIa)-O(2) = 2.138(12) Å, Zn(IIb)-O(2) = 2.28(4) Å, O(2)-Zn(IIa)-O(2) = 114.2(10)°, and O(2)-Zn(IIb)-O(2) = 103.7(25)°).     

Wetting of plasma-sprayed coatings of SrAl2Si2O8 (SrASi), BaAl2Si2O8 (BASi) and Sr4Al6O12SO4 (SAlSr) by Al-12Si alloy

The wettability of SrAl₂Si₂O₈ (SrASi), BaAl₂Si₂O₈ (BASi) and Sr₄Al₆O₁₂SO₄ (SAlSr) plasma-sprayed coatings on mullite substrates by an Al-12Si alloy at 1000 °C was studied using the sessile drop technique. All the coatings showed high adherence to the substrate. The SrASi and BASi coatings were mainly amorphous with some monoclinic crystallites of SrAl₂Si₂O₈ and BaAl₂Si₂O_8, respectively. The SAlSr coating was amorphous and contained Sr, Al and O, indicating a decomposition during the coating process. The average contact angles for BASi, SrASi and SAlSr coatings were 121, 122 and 124°, respectively, showing a non-wetting behavior. Coatings of BASi and SAlSr after the wetting experiments presented no reaction with aluminum, while the SrASi coating showed the formation of an alumina layer as a reaction product, indicating a slight reduction of the Sr-celsian by aluminum. In general, these coatings are suitable to enhance the corrosion resistance of aluminosilicate ceramics in contact with Al alloys.     

Structure of a methylamine sorption complex of fully dehydrated Cd-exchanged zeolite X, Cd46(CH3NH2)16[Si100Al92O384]-FAU

The structure of a methylamine sorption complex of fully dehydrated, fully Cd²⁺-exchanged zeolite X, Cd₄₆(CH₃NH₂)₁₆[Si₁₀₀Al₉₂O₃₈₄]-FAU (a = 24.863(4) Å), has been determined by single-crystal X-ray diffraction techniques in the cubic space group at 21(1) °C. An aqueous exchange solution 0.05 M in Cd²⁺ was allowed to flow past the crystal for 5 days. The crystal was then dehydrated at 480 °C and 2 × 10⁻⁶ Torr for 2 days (colorless), and exposed to 160 Torr of methylamine gas at 21(1) °C for 2 h (yellow). Diffraction data were then gathered in this atmosphere and were refined using all data to the final error indices (based upon the 524 reflections for which F_o > 4σ(F_o)) of R₁ = 0.069 and wR₂ = 0.200. In this structure, Cd²⁺ ions occupy three crystallographic sites. The octahedral sites I at the centers of the hexagonal prisms are filled with 16 Cd²⁺ ions per unit cell (Cd–O = 2.369(8) Å). The remaining 30 Cd²⁺ ions are located at two non-equivalent sites II with occupancies of 14 and 16. The 16 methylamine molecules per unit cell lie in the supercage where each interacts with one of the latter 16 site-II Cd²⁺ ions: N–Cd = 2.11(8) Å. The imprecisely determined N–C bond length, 1.49(22) Å, agrees with that in gaseous methylamine, 1.474 Å. The positions of the hydrogen atoms were calculated. It appears that one of the amino hydrogen atoms hydrogen bonds to a 6-ring oxygen, and that the other forms a bifurcated hydrogen bond to this and another 6-ring oxygen. The methyl group is not involved in hydrogen bonding.     

A mixed-type of azametallacrown containing [Mn6(pnhz)6(DMF)4(H2O)2] and [Mn6(pnhz)6(DMF)2(H2O)4] constructed by a flexible pentadentate ligand

A mixed-type of azametallacrown based on a flexible pentadentate N-propionyl ligand was reported, which exhibits not only the completely different arrangement of the metal centers but also diversely geometric configurations of the N-terminal ligands, and this complex can further assemble into a novel 3-D supramolecular structure using two different aza18-MC-6 as secondary building units (SBUs) via the intermolecular C–H?π, π–π and C–H?O interactions. Temperature-dependent magnetic susceptibility measurements of the title complex indicate that the complex presents significantly antiferromagnetic coupling among metal centers.     

Observation of [Al(OH) n (H2O)6-n ] n (MoO4) in hydrotreating catalyst precursors by solid-state27 Al NMR

A previously unobserved octahedral²⁷Al MAS NMR resonance has been detected in rehydrated calcined Mo/Al₂O₃ hydrotreating catalyst precursors. This resonance is attributed to the presence of hydrated forms of aluminum molybdate such as [Al(OH) _n (H₂O)_6-n ] _n (MoO₄) (n = 1 or 2). The cross-polarization relaxation parameters, obtained from variable contact time experiments, yielded information on the relative sizes of the [Al(OH) _n (H₂O)_6-n ] _n (MoO₄) domains in the catalysts with different molybdenum loadings. Analysis of the²⁷A1 MAS NMR spectra of P-Mo(8)/Al₂O₃ and P-Mo(12)/Al₂O₃ (wt%P = 0.0–12.0) shows that a function of the phosphate in the 12 wt% Mo catalyst is to prevent the re-hydration of the molybdate phases on the calcined catalysts.     

DNA-Binding Study of Tetraaqua-bis(p-nitrobenzoato)cobalt(II) Dihydrate Complex: [Co(H2O)4(p-NO2C6H4COO)2]·2H2O

The interaction of [Co(H₂O)₄(p-NO₂C₆H₄COO)₂]^· 2H₂O with sheep genomic DNA has been investigated by spectroscopic studies and electrophoresis measurements. The interaction between cobalt(II) p-nitrobenzoate and DNA has been followed by gel electrophoresis while the concentration of the complex was increased from 0 to 14 mM. The spectroscopic study and electrophoretic experiments support the fact that the complex binds to DNA by intercalation via p-nitrobenzoate into the base pairs of DNA. The mobility of the bands decreased as the concentration of complex was increased, indicating that there was increase in interaction between the metal ion and DNA.     

[Nd(6-OHnicH)3(H2O)6]n配合物的合成和晶体结构研究

在水热反应条件下,采用6-羟基吡啶-3-甲酸(6-OHnicH)与稀土金属离子钕合成了标题化合物。运用元素分析、红外光谱、X-射线衍射等进行了表征。X-射线衍射结果表明:该配合物属于三斜晶系,空间群是P-1,晶胞参数为:a=7.1693(8),b=10.3227(12),c=16.7831(19),α=73.3000(10)°,β=88.0070(10)°,γ=88.2180(10)°,Z=2。该配合物最终通过分子间氢键作用堆积为三维网状结构。     

First X-ray crystal structure of cation [cis-Co(en)2(H2O)Cl]2+: Synthesis,spectroscopic and X-ray structural study of [cis-Co(en)2(H2O)Cl](C6H5SO3)2·H2O

A new cobalt(III) complex salt, [cis-Co(en)₂(H₂O)Cl](C₆H₅SO₃)₂ · H₂O] (I) has been synthesized and characterized by single crystal X-ray structure determination and NMR spectroscopy. This is a first report of the cobalt(III) cation in cis-configuration. The crystal lattice of the complex salt is stabilized by electrostatic forces of attraction and hydrogen bonding interactions.     

Hydrothermal synthesis and crystal structure of a new copper(II) molybdenum(VI) arsenate(III), (C5H5NH)2(H3O)2[(CuO6)Mo6O18(As3O3)2]

A new copper(II) molybdenum(VI) arsenate(III), (C₅H₅NH)₂(H₃O)₂[(CuO₆)Mo₆O₁₈(As₃O₃)₂], has been hydrothermally synthesized and characterized by single crystal X-ray diffraction and TG analysis. The compound crystallizes in the monoclinic space group P2₁/n with a=9.303(2), b=20.731(4), c=12.617(3) Å, β=104.17(3)°, V=2359.3(8) ų, Z=2 and R1(wR2)=0.0296(0.0683). The structure is composed of pyridinium cations, proton hydrates and [(CuO₆)Mo₆O₁₈(As₃O₃)₂]⁴⁻ polyanions. The polyanion framework derives from the Anderson type; the central octahedron is filled up by copper(II) and is capped on both sides by a cyclic As₃O₆ group.     

三维超分子化合物[Zn(C6H4O2N)2·(H2O)4]n的水热合成及晶体结构

用2-羧基吡啶和六水合氯化锌反应制备了一种新的三维氢键超分子配合物,经X-射线衍射分析确定了单晶结构。该晶体属单斜晶系,P2(1)/n空间群,晶胞参数为:a=9.836(2),b=5.2256(10),c=14.611(3),Mr=381.64,β=90.01(3)°,V=751.0(3)3,Z=2,Dc=1.688Mg.m-3,F(000)=392,μ=1.680mm-1,R=0.0258,wR=0.0612。共收集2159个衍射数据,其中1273个为独立衍射点(Rint=0.0332),可观测点数1139个(I>2σ(I))。结果表明,在组成该超分子体系的基本结构单元[Zn(C6H4O2N)2.(H2O)4]中,Zn(Ⅱ)离子形成六配位的畸变的八面体构型,配合物单元之间通过氢键OH…O相互连接,形成了无限延伸的具有网状结构的三维超分子体系。     

溶剂热法合成有机金属框架材料Co_2(C_8O_6H_4)_2·4H_2O

采用溶剂热法合成了一种新的金属有机配合物[Co2(C8O6H4)2·(H2O)4],通过X射线单晶衍射技术对该化合物进行了结构表征。结果表明,该化合物晶体属三斜晶系,空间群为P1;晶胞参数a=9.389(2)(1=10-10 m),b=9.421(3),c=12.209(3);α=101.846(2)°;β=104.453(2)°;γ=105.305(3)°;V=965.23;Z=2;Dc=2.003g/cm3,μ=1.810mm-1,F(000)=588,GooF=1.044,R1=0.0268,ωR2=0.023 0[I2σ(I)]。     

[Zn(H2O)4][B6O10]: An open-framework borate with acentric structure

An open-framework borate [Zn(H₂O)₄][B₆O₁₀] with acentric structure, has been successfully obtained for the first time under solvothermal conditions. It has been characterized by powder and single crystal X-ray diffraction, IR spectroscopy, diffuse-reflectance spectroscopy and thermogravimetric (TG) analyses, respectively. It crystallizes in the orthorhombic system, space group Pna2₁, a = 11.3140(6) Å, b = 11.8995(7) Å, c = 8.6140(5) Å and Z = 4. In the structure, the alternative connections between [B₃O₇] units give rise to an unprecedented 3D borate framework with 11- and 10-MR channels, in which the [Zn(H₂O)₄]²⁺ complexes are located. It has a cut-off edge below 200 nm and exhibits second harmonic generation (SHG) efficiency approximately 0.4 times that of KH₂PO₄ (KDP).     

三维超分子化合物[Zn(C6H4O2N)2·(H2O)4]n的水热合成及晶体结构

用2-羧基吡啶和六水合氯化锌反应制备了一种新的三维氢键超分子配合物,经X-射线衍射分析确定了单晶结构.该晶体属单斜晶系,P2(1)/n空间群,晶胞参数为a=9.836(2)(A),b=5.2256(10)(A),c=14.611(3)(A),Mr=381.64,β=90.01(3)°,V=751.0(3)(A)3,Z=2,Dc=1.688Mg·m-3,F(000)=392,μ=1.680mm-1,R=0.0258,wR=0.0612.共收集2159个衍射数据,其中1273个为独立衍射点(Rint=0.0332),可观测点数1139个(I＞2σ(I)).结果表明,在组成该超分子体系的基本结构单元[Zn(C6H4O2N)2·(H2O)4]中,Zn(Ⅱ)离子形成六配位的畸变的八面体构型,配合物单元之间通过氢键OH…O相互连接,形成了无限延伸的具有网状结构的三维超分子体系.     

Polymerization of epoxides catalyzed by a mixed‐valent iron trifluoroacetate [Fe3O(O2CCF3)6(H2O)3]

The readily available mixed‐valent iron trifluoroacetate complex [Fe₂^IIIFe^II(µ₃‐O)(O₂CCF₃)₆(H₂O)₃] is an effective catalyst for the polymerization of epoxides. A very small amount of the catalyst (1.0–0.01 mol%) could initiate the polymerization of cyclohexene oxide, cyclopentene oxide and epichlorohydrin. Based on quantitative end‐group analysis by ¹⁹F NMR spectroscopy, a Lewis acid (LA^⊕) catalyzed anionic reaction mechanism is proposed. Copyright © 2012 Society of Chemical Industry     

Synthesis and crystal structures of two new inorganic–organic hybrid polyoxomolybdate complexes: [Himi]4[{Co(imi)2(H2O)2}Mo7O24] · 4H2O and [Zn(imi)4]2[(imi)2Mo8O26] · 6H2O

The two new inorganic–organic hybrid polyoxomolybdate complexes [Himi]₄[{Co(imi)₂(H₂O)₂}Mo₇O₂₄] · 4H₂O (1) and [Zn(imi)₄]₂[(imi)₂Mo₈O₂₆] · 6H₂O (2) (imi = imidazole) have been prepared by conventional aqueous solution synthesis. Compound 1 consists of heptamolybdate anions [Mo₇O₂₄]⁶⁻ covalently linked by [CoN₂O₄]²⁺ octahedra into one-dimensional zigzag-shaped chains. The zigzag-shaped chains are further linked together via the hydrogen-bonding interactions to form a 2D supramolecular framework. Compound 2 is build up of an imidazole-coordinated octamolybdate anion, two imidazole coordinating zinc cations and lattice water molecules to form a three-dimensional framework via complex hydrogen-bonding.     

A new binuclear Cr(III) citrate anion: Synthesis,characterization and crystal structure of [Cr(CO(NH2)2)6]2[Cr2(CO(NH2)2)2(C6H4O7)2]3

The new anion [Cr₂(CO(NH₂)₂)₂(C₆H₄O₇)₂]^2 − has been isolated in the complex [Cr(CO(NH₂)₂)₆]₂[Cr₂(CO(NH₂)₂)₂(C₆H₄O₇)₂]₃. The crystals of this complex were obtained by a one-pot synthetic method using 1:1 molar ratio of hexaureachromium(III) chloride and trisodium citrate in aqueous medium. It was characterized by elemental analysis, IR spectroscopy and single crystal X-ray diffraction analysis. The compound crystallizes in space group R‾3 of the trigonal system with three formula units in a cell of dimensions a = b = 24.7461(4) Å, c = 13.7204(3) Å and γ = 120°. The crystal structure comprises the columns consisting of [Cr(CO(NH₂)₂)₆]^3 + cations surrounded by a cylinder of complex anions, [Cr₂(CO(NH₂)₂)₂(C₆H₄O₇)₂]^2 − which are packed in a honeycomb-like manner. This supramolecular architecture is formed and stabilized by inter- and intramolecular NH⋯O hydrogen bonds.     

The synthesis and single-crystal X-ray structure of the first mononuclear iridium carbonyl hydride with two orthometallated phosphite ligands,cis-[IrHCO{P(O-o-tBuC6H3) (O-o-tBuC6H4)2}2]

[Ir(μ-OMe)(COD)]₂ reacts with tris-ortho-tert-butylphenylphosphite in the presence of carbon monoxide to give the first example of a mononuclear iridium carbonyl hydride complex with two orthometallated phosphite ligands cis-[IrHCO{P(O-o-^tBuC₆H₃) (O-o-^tBuC₆H₄)₂}₂]. The complex shows great stability even under high pressures of hydrogen and carbon monoxide.     

二维层状超分子化合物[Mn（C8H5NO6）（H2O）2]n的合成及晶体结构研究

分子间的弱相互作用在配位化合物中往往表现为配合物分子内和(或)分子间的配体间相互作用。因此,研究配合物中的配体间弱相互作用就成为由配位化学向超分子化学过渡的桥梁。本文以锰离子为中心离子,以2,4,6-吡啶三羧酸为配体进行晶体合成实验。通过检测手段了解了合成的配合物配体间的弱相互作用。     

Characterization of metal (Ba, Al, Si, V, and W)-incorporated TiO2 and toluene photodecomposition in the presence of H2O

This study focused on toluene photodecomposition in the presence of H₂O over metal (Ba, Al, Si, V, and W)-incorporated TiO₂. The nanometer-sized, metal-TiO₂ photocatalyst samples, including Ba²⁺, Al³⁺, Si⁴⁺, V⁵⁺, and W⁶⁺ ions, were prepared by using the solvothermal method. The X-ray photoelectron spectroscopy (XPS) results showed that the Ti-OH peak, which indicates hydrophilicity, increased with increasing Al and Si ion components but decreased with increasing Ba, V, and W ion components. The contact angles were distributed over the range of 0–10° on almost all films (200-nm thick) after irradiation for 2 h, and in particular approached 0° on the Al-TiO₂ and Si-TiO₂ nanometer-sized films after just 30 min. The toluene (100 ppm) photodecomposition in the continuous system increased in the order of Al-TiO₂>Si-TiO₂>pure TiO₂>W-TiO₂>Ba-TiO₂>V-TiO₂, and the maximum toluene conversion rate achieved was 45% over Al-TiO₂ film after 120 min. The toluene conversion remarkably increased; however, over all photocatalysts, with H₂O addition during the toluene photo-decomposed reaction, and in particular, the conversion reached up to 90% after 120 min over Al-TiO₂ and Si-TiO₂ with increased hydrophilicity. After photoreaction for 24 h, minimal carbon was deposited on the photocatalyst under both reaction conditions, with and without H₂O addition, although the deposited carbon amounts were smaller for the former. These results confirmed that the hydrophilicity of the photocatalyst had a greater effect on toluene decomposition, while the photocatalytic deactivation could be retarded by H₂O supplementation during toluene decomposition.