Noncentrosymmetric K2Mn3(SO4)3F2·4H2O and Rb2Mn3(SO4)3F2·2H2O with pseudo-KTP structures

Two fluoride sulfates,K₂Mn₃(SO₄)₃F₂·4H₂O(Ⅰ) and Rb₂Mn₃(SO₄)₃F₂·2H₂O (Ⅱ) are obtained by water solution method.Single-crystal X-ray diffraction analysis indicated that they crystallize in space groups of Cmc2_1.Their structures feature a pseudo-KTP structure consisting of interconnecting[Mn₃(SO₄)3F₂(H₂O)2]_∞ layers,which are further packing along the a axis with alkali metal cations balancing the charges.The structure relationships between the two compounds are discussed.Secondharmonic generation measurements manifest that Ⅰ and Ⅱ have similar second-harmonic generation responses of about 0.2 and 0.25 times that of KH₂PO₄.     

Spanning [Pt2(μ-S)2(PPh3)4] metalloligands with 1,4-dimercurated durene

Reaction of the metalloligand [Pt₂(μ-S)₂(PPh₃)₄] with 0.5 mol equivalents of durene-1,4-bis(mercuric acetate) [AcOHgC₆Me₄HgOAc] in methanol gives the polynuclear complex [{Pt₂(μ-S)₂(PPh₃)₄}₂(μ-1,4-C₆Me₄Hg₂)]²⁺, isolated as its and salts. Positive-ion ESI mass spectra indicate that [{Pt₂(μ-S)₂(PPh₃)₄}₂(μ-1,4-C₆Me₄Hg₂)]²⁺ undergoes fragmentation by successive loss of PPh₃ ligands, while the ESI mass spectrum of the salt showed additional ions [Pt₂(μ-S)₂(PPh₃)₄(HgC₆Me₄HgPh)]⁺ and [Pt₂(μ-S)₂(PPh₃)₄HgPh]⁺ as a result of phenyl transfer from to Hg. A single-crystal X-ray structure determination on [{Pt₂(μ-S)₂(PPh₃)₄}₂(μ-1,4-C₆Me₄Hg₂)](BPh₄)₂ shows that the cation crystallises on a centre of symmetry, with structural features that are comparable to those of the previously characterised complex [Pt₂(μ-S)₂(PPh₃)₄HgPh]BPh₄.     

Syngas production from methane reforming with O2 and CO2 over Ni–La2O3/SiO2 catalysts using EDTA salt precursors

Ni–La₂O₃/SiO₂ catalysts (NLS) were prepared by the incipient-wetness impregnation method using EDTA salt precursors. XRD measurements revealed that the promoter of La₂O₃ is highly dispersed on the NLS. The TPR profiles indicated a strong interaction between NiO and La₂O₃ to form a La–Ni complex oxide like species over the NLS, which may be the origin of its high catalytic performance.     

Oxidative cleavage of α-sulfonyl ketones to carboxylic acids with Ce(NH4)2(NO3)6

Tandem oxidative cleavage of α-sulfonyl arylketones 2 with the combination of Ce(NH₄)₂(NO₃)₆ and O₂ in MeCN afforded carboxylic acids 3 in moderate to good yields. The plausible reaction mechanism has been discussed.     

Trifluoromethylation of carbon and boron with CF3SiMe3/NMe4F: formation of NMe4[trans-CF3CFCFB(CF3)3]

Trimethylamine-trifluoroethenyl-bis(trifluoromethyl)borane [F₂CCF(CF₃)₂B·NMe₃] (1) reacts with NMe₄[(CF₃)₂SiMe₃] in THF solution to form trimethylamine-bis(trifluoromethyl)pentafluoropropenylborane [trans-CF₃CFCF(CF₃)₂B·NMe₃] (3), the fluoroborate NMe₄[trans-CF₃CFCF(CF₃)₂BF] (4), the novel borates NMe₄[trans-CF₃CFCFB(CF₃)₃] (5) and NMe₄[cyclo-(CF₃)₂BCF₂CFCF₂CF₃] (6).     

Electrochemical urea synthesis by co-reduction of CO2 and nitrate with FeⅡ-FeⅢOOH@BiVO4 heterostructures

Traditional urea synthesis under harsh conditions is usually associated with high energy input and has aroused severe environmental concerns.Electrocatalytic C-N coupling by converting nitrate and CO₂ into urea under ambient conditions represents a promising alternative process.But it was still limited by the strong competition between nitrate electrochemical reduction(NO₃ER) and CO₂ electrochemical reduction(CO₂ER).Here,Fe^Ⅱ-Fe^ⅢOO...     

Synthesis and structures of Cs4[(UO2)2(C2O4)(SO4)2(NCS)2] · 4H2O and (NH4)4[(UO2)2(C2O4)(SO4)2(NCS)2] · 6H2O

Single crystals of Cs₄[(UO₂)₂(C₂O₄)(SO₄)₂(NCS)₂] · 4H₂O (I) and (NH₄)₄[(UO₂)₂(C₂O₄)(SO₄)₂(NCS)₂] · 6H₂O (II) have been synthesized and studied by X-ray diffraction. The crystals of both compounds are orthorhombic with the space group Pbam, Z = 2, and unit cell parameters a = 12.0177(3) ?, b = 18.6182(5) ?, c = 6.7573(10) ?, R = 0.0376 (I); a = 11.6539(9) ?, b = 18.3791(13) ?, c = 6.7216(5) ?, R = 0.0179 (II). The main structural units of crystals I and II are [(UO₂)₂(C₂O₄)(SO₄)₂(NCS)₂]⁴⁻ chains belonging to the crystal-chemical group A₂K⁰²B₂²M₂¹ (A = UO₂²⁺, K⁰² = C₂O₄²⁻, B² = SO₄²⁻, M¹ = NCS⁻) of the uranyl complexes. The uranium-containing chains are joined into a three-dimensional framework due to a system of electrostatic interactions with the cesium or ammonium ions in the structure of I. In the structure of II, this framework is additionally stabilized by hydrogen bonds involving the outer-sphere water molecules and ammonium ions. Original Russian Text ? I.V. Medrish, A.V. Virovets, E.V. Peresypkina, L.B. Serezhkina, 2008, published in Zhurnal Neorganicheskoi Khimii, 2008, Vol. 53, No. 7, pp. 1115–1120.     

Synthesis,X-ray crystal structure and thermal decomposition of two peroxovanadium complexes with coordinated ammonia molecules: [{VO(O2)2(NH3)}2{μ-Cu(NH3)4}] and [Zn(NH3)4][VO(O2)2(NH3)]2

The compounds [{VO(O₂)₂(NH₃)}₂{μ-Cu(NH₃)₄}] (1) and [Zn(NH₃)₄][VO(O₂)₂(NH₃)]₂ (2) were prepared and characterized by elemental analysis and infrared spectra. The single crystal X-ray study revealed that the structure of 1 consists of trinuclear complex molecules [(NH₃)OV(O₂)₂{μ-Cu(NH₃)₄}(O₂)₂VO(NH₃)] with a rare heterobimetalic peroxo bridge: copper(II)–peroxo ligand–vanadium(V). The structure of 2 is composed of tetraamminezinc(II) cations and ammineoxodiperoxovanadate(V) anions. In course of thermal decomposition of 1 performed up to 620 °C, the following intermediate products: [Cu(NH₃)₂(VO₃)₂], and subsequently a mixture of V₂O₅ with monoclinic β-Cu₂V₂O₇, were gradually formed. The final product of decomposition is Cu(VO₃)₂. The thermal decomposition of 2 is a two-step process. In the first stage, [Zn(NH₃)₃(VO₃)₂] as supposed intermediate was formed, which transformed at higher temperatures by release of ammonia molecules to the monoclinic modification of Zn(VO₃)₂.     

Synthesis of Mo(CO)2(η-PPh2(o-C6H4)C(O)H)2 and its reaction with C60

Reaction of Mo(CO)₃(NCMe)₃ and PPh₂(o-C₆H₄)C(O)H (abbreviated as PCHO) at room temperature affords Mo(CO)₂(η³-PCHO)₂ (1), while compound 1 and the phosphine-imine complex Mo(CO)₄(η²-PPh₂(o-C₆H₄)CHNMe) (2) are obtained by using Mo(CO)₃(η³-(MeNCH₂)₃) as the reactant. Thermal reaction of 1 with C₆₀ products Mo(CO)₂(η⁴-(PPh₂(o-C₆H₄)CH)₂)(η²-C₆₀) (3) in low yield, apparently through coupling of the formyl moieties. The structures of 1 and 3 have been determined by an X-ray diffraction study. The two aldehyde groups of 1 and C₆₀ ligand of 3 are coordinated to the molybdenum atom in a π-fashion.     

A comparison between the reaction of P2Ph4 with [{Co2(CO)6}2(μ-η:μ-η-HOCH2CCCCCH2OH)] and the reaction of [Co2(μ-PPh2)2(CO)6] with HOCH2CCCCCH2OH

Reaction of P₂Ph₄ with the diyne-diol complex [{Co₂(CO)₆}₂(μ-η²:μ-η²-HOCH₂CCCCCH₂OH)] in toluene at 65 °C gives [{Co₂(μ-P₂Ph₄)(CO)₄}{Co₂(CO)₆}(μ-η²:μ-η²-HOCH₂CCCCCH₂OH)] (1). Thermolysis of 1 at 95 °C leads to [{Co₂(CO)₅}₂(μ-P₂Ph₄)(μ-η²:μ-η²-HOCH₂CCCCCH₂OH)](2) and (μ₂-PPh₂)(μ₂-CO)(CO)₇] (3). The structures of 1-3 have been established by X-ray crystallography. In 1, a pseudoequatorial P₂Ph₄ ligand bridges the cobalt-cobalt bond of a Co₂(CC)(CO)₄ unit. By contrast, in isomeric 2, a pseudoaxial P₂Ph₄ ligand spans two Co₂(CC)(CO)₅ units, a new coordination mode for [{Co₂(CO)₅L}₂(μ-η²:μ-η²-diyne)] complexes. Complex 3 arises from dehydration-cyclocarbonylation of the diyne-diol in 1 to give a 2(5H)-furanone, a process that has not been previously reported. Reaction of HOCH₂CCCCCH₂OH with [Co₂(μ-PPh₂)₂(CO)₆] at 80 °C in toluene gave [Co₃(μ-PPh₂)₃(CO)₆], [Co₂(CO)₆(μ-η²-HOCH₂CCCCCH₂OH)] and [Co₂{μ-η⁴-PPh₂C(CCCH₂OH)C(CH₂OH)CO}(μ-PPh₂)(CO)₄] (4). The regiochemistry of 4 was confirmed by X-ray crystallography.     

Cr2(WO4)3和Cr2(MoO4)3的负热膨胀特性研究

用液相反应-前驱物烧结法制备了Cr₂(WO₄)₃和Cr₂(MoO₄)₃粉体。298～1 073 K的原位粉末X射线衍射数据表明Cr₂(WO₄)₃和Cr₂(MoO₄)₃的晶胞体积随温度的升高而增大, 本征线热膨胀系数分别为(1.274±0.003)×10^-6 K^-1和(1.612±0.003)×10^-6 K^-1。用热膨胀仪研究了Cr₂(WO₄)₃和Cr₂(MoO₄)₃在静态空气中298～1 073 K范围内热膨胀行为，即开始表现为正热膨胀，随后在相转变点达到最大值，最后表现为负热膨胀，其负热膨胀系数分别为(-7.033±0.014)×10^-6 K^-1和(-9.282±0.019)×10^-6 K^-1。     

A 4D Structural Study of a Ca-Rich Composite-Type Crystal [A2Cu2O3]7+δ [CuO2]10 with Disorder Phenomena in CuO2 Sublattice

The structure of a Ca-rich composite-type crystal [A₂Cu₂O₃]_7+δ [CuO₂]₁₀ with A=Sr_0.43Ca_0.55Bi_0.03 and δ=0.04 was determined by single-crystal X-ray diffraction using the 4D superspace group formalism. Thanks to the existence of a significant number of first-order satellite reflections, reliable results were obtained concerning the displacive modulation within each subsystem. A comparison is made with the accurate structural results obtained by Frost Jensen on similar composite crystals containing less calcium. A larger modulation amplitude is observed in our crystal. Weak interactions (Cu-O?2.72 Å) are involved locally between the copper atoms of a [Cu₂O₃] layer and one oxygen atom of a [CuO₂] layer, leading in some unit cells to a pyramidal coordination of copper. Such an interaction is not observed in the Ca-less-containing crystal of Frost-Jensen. However, the most important point of this study concerns the evidence for the first time of disorder phenomena inside the [CuO₂] subsystem; this disorder was modeled with both Cu and O splitted sites. Two main configurations with realistic Cu-O bonds are privileged for the CuO₄ squares inside the [CuO₂] sublattice. The refinement results and the bond valence formalism give strong evidence that the A sites are occupied at random by Sr and Ca atoms, which display two types of coordination, 7 and 8, in the crystal.     

Ce0.67Zr0.33O2对CH4燃烧催化剂Fe2O3/Al2O3的改性作用

固定n(Ce)/n(Zr)比为0.67/0.33,用共沉淀法制得一系列CeO2-ZrO2-Al2O3固溶体.采用这些固溶体作载体,以Fe2O3为活性组分,用浸渍法制备了一系列催化剂.BET结果显示,将适量Ce0.67Zr0.33O2引入到Al2O3载体中有助于催化剂保持较高的比表面积.TPR结果显示,载体中引入适量的Ce0.67Zr0.33O2可以改善催化剂的氧化还原性能.XRD结果表明,Fe2O3在CeO2-ZrO2-Al2O3载体上呈现出良好的分散状况,老化前后催化剂的晶相结构基本无明显变化.特别是当载体中m(Ce0.67Zr0.33O2)∶m(Al2O3)的值为1∶2时,Fe2O3/CeO2-ZrO2-Al2O3催化剂在甲烷催化燃烧中显示出最佳的催化性能和抗高温老化性能.     

Crystal structure of K2[Mo3(PdPPh3)S4(C2O4)3(H2O)3]·0.5H2O

By the reaction of [Mo₃S₄(C₂O₄)₃(H₂O)₃]²⁻ with PdCl₂ and NH₄H₂PO₂ as a reducing agent, followed by the addition of PPh₃, a new oxalate cuboidal cluster complex [Mo₃(PdPPh₃)S₄(C₂O₄)₃(H₂O)₃]²⁻ is obtained. It was isolated and structurally characterized as K₂[Mo₃(PdPPh₃)S₄(C₂O₄)₃(H₂O)₃]·0.5H₂O. Original Russian Text Copyright ? 2008 by A. L. Gushchin, M. N. Sokolov, D. Yu. Naumov, and V. P. Fedin __________ Translated from Zhurnal Strukturnoi Khimii, Vol. 49, No. 4, pp. 775–778, May–June, 2008.     

A Supramolecular Star-like Tungstoarsenate(V) with Uranyl Cations: [(NH4)12(UO2(H2O))6(UO2(μ2-H2O))6(α-AsW9O34)6]18?

A supramolecular tungstoarsenate(V) containing UO₂ ²⁺ cations has been isolated by reaction of the ammonium salt of lacunary sandwich-type anion [As₂W₁₈(UO₂)₂O₆₈]¹⁴⁻ in aqueous solution of Ce^IV (pH 3.5). The product prepared as NH₄ ⁺ salt, (NH₄)₁₈[(NH₄)₁₂(UO₂(H₂O))₆(UO₂(μ₂-H₂O)₆(α-AsW₉O₃₄)₆]·74H₂O (I), have been characterized by single crystal X-ray diffraction, elemental analysis, IR, and UV/vis spectroscopy. The anion consists on six lacunary α-AsW₉O₃₄ ⁹⁻ anions linked by twelve UO₂ ²⁺ cations which resembles a star (six-member). The single crystal structure of I reveals two types uranium atoms; six uranium atoms in the central of anion form two U₃O₃ trigonal bridging groups in which each uranium atom bounds to three oxygen atoms of one AsW₉ and two bridging water ligands. The other uranium atoms form two equatorial bonds to one AsW₉ and two equatorial bonds to two other AsW₉ fragments. The UV/vis spectroscopy confirms the strong coordination of oxygen atoms of α-AsW₉O₃₄ ⁹⁻ anions to uranyl cations in the equatorial plane.     

Ce0.67Zr0.33O2对CH4燃烧催化剂Fe2O3/Al2O3的改性作用

固定n(Ce)/n(Zr)比为0.67/0.33, 用共沉淀法制得一系列CeO2-ZrO2-Al2O3固溶体. 采用这些固溶体作载体, 以Fe2O3为活性组分, 用浸渍法制备了一系列催化剂. BET结果显示, 将适量Ce0.67Zr0.33O2引入到Al2O3载体中有助于催化剂保持较高的比表面积. TPR结果显示, 载体中引入适量的Ce0.67Zr0.33O2可以改善催化剂的氧化还原性能. XRD结果表明, Fe2O3在CeO2-ZrO2-Al2O3载体上呈现出良好的分散状况, 老化前后催化剂的晶相结构基本无明显变化. 特别是当载体中m(Ce0.67Zr0.33O2)∶m(Al2O3)的值为1∶2时, Fe2O3/CeO2-ZrO2-Al2O3催化剂在甲烷催化燃烧中显示出最佳的催化性能和抗高温老化性能.     

Reactivity of the heteronuclear cluster RuOs3(μ-H)2(CO)13 with indene

The heteronuclear cluster RuOs₃(μ-H)₂(CO)₁₃ (1) reacts with indene under thermal activation to afford the novel clusters RuOs₃(μ-H)(CO)₉(μ-CO)₂(η⁵-C₉H₇) (3), RuOs₃(μ-H)(CO)₉(μ₃,η⁵:η²:η²-C₉H₇) (4) and Ru₂Os₃(μ-H)(CO)₁₁(μ₃,η⁵:η²:η²-C₉H₇) (5), the latter two possessing indenyl ligands in the μ₃,η⁵:η²:η² bonding mode. Cluster 5 exists as a mixture of two isomers. The inter-relationship among the clusters has also been investigated.     

Vapor phase methylation of pyridine with CO?H2 and CO2?H2 over a Ni catalyst

Pyridine was methylated selectively to 2-picoline with CO−H₂ and with CO₂−H₂ over a Ni catalyst. 2,6-lutidine was producedvia the methylation of 2-picoline.     

Li3V2(PO4)3/C和Li2.5Na0.5V2(PO4)3/C的结构和电化学性能的比较研究

采用溶胶-凝胶法合成了锂离子正极材料Li3V2(PO4)3/C(LVP/C)及Li2.5Na0.5V2(PO4)3/C,并用XRD、循环伏安及交流阻抗等方法,研究了大量Na+掺杂对材料结构和电化学性能影响。结果表明,大量钠离子的掺杂会使LVP结构由单斜向菱方转变。掺杂化合物Li2.5Na0.5V2(PO4)3/C在0.5 C充电1 C放电时,首次放电容量为118 mAh.g-1,50次循环后容量保持率为92.4%,并发现与单斜LVP存在多个放电平台不同,Li2.5Na0.5V2(PO4)3/C仅在3.7 V处有一个放电平台。