Synthesis and crystal structure of [W3S4(Acac)3(PPh3)3]PF6 · 0.5CHCl3 and [W3S4(Hfac)3(PPh3)2Br] · 2CHCl3

New cluster complexes [W₃S₄(Acac)₃(PPh₃)₃]PF₆ · 0.5CHCl₃ (Acac = CH₃C(O)CHC(O)CH₃) (I) and [W₃S₄(Hfac)₃(PPh₃)₂Br] · 2CHCl₃ (Hfac = CF₃C(O)CHC(O)CF₃) (II) were synthesized. Their molecular and crystal structures were determined by X-ray diffraction. The cis-cis type of coordination of acetylacetonate and hexafluoroacetylacetonate ligands in I and II, respectively, was established, and the PPh₃ ligands were found in the trans-positions with respect to the “capping” sulfide ligand (μ³-S).     

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).     

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.     

Deuterium exchange reaction of ethylbenzene over an Fe2O3?K2CO3?Cr2O3 catalyst

Isotope exchange reaction of ethylbenzene with water or hydrogen has been examined over Fe₂O₃–K₂CO₃–Cr₂O₃ catalyst. The participation of the hydrogen attached to -carbon or phenyl group was observed. The exchange rate of the -hydrogen was compared for different alkylbenzenes and found that toluene was the most active, whereas cumene was inactive. This order suggested that the -hydrogen dissociated as a proton. -Adsorbed state was supposed as an intermediate of dehydrogenation, which dissociates the -hydrogen reversibly as a proton on a basic site. Including the results of exchange reaction of styrene, the overall route of dehydrogenation is discussed.     

Copper-catalyzed synthesis of aryl and alkyl trifluoromethyl sulfides using CF3SiMe3 and Na2S2O3 as –SCF3 source

A universal and efficient Cu(I)-catalyzed synthesis of aryl and alkyl trifluoromethyl sulfides has been developed. In this catalytic system, S-aryl or S-alkyl sulfothioate (I or II) proved to be the key intermediate. Substrates bearing groups of I, Br, Cl, OTs, and OMs on the aryl carbon and no matter electron-withdrawing and electron-donating substitutions on the aromatic ring could afford good to excellent yields.     

Synthesis and crystal structure of [Mo3S4(Dppen)3Cl3]PF6 · 1.5CH2Cl2 and [W3S4(Dppe)3Br3]2ZnBr4 · 5.5CH3CN

New cluster complexes [Mo₃S₄(Dppen)₃Cl₃]PF₆ · 1.5CH₂Cl₂ (Dppen = cis-Ph₂PCH=CHPPh₂) (I) and [W₃S₄(Dppe)₃Br₃]₂(ZnBr₄)₂ · 5.5CH₃CN (Dppe = Ph₂PCH₂CH₂PPh₂) (II) were synthesized. Their molecular and crystal structures were determined by X-ray diffraction. Diphoshine ligands in the complexes I and II are coordinated in the bidentate mode, providing an arrangement of three chelate rings, giving rise to chirality.     

Crystal structure of [Pd(NH3)4]3[Ir(NO2)6]2·H2O

A single crystal of [Pd(NH₃)₄]₃[Ir(NO₂)₆]₂·H₂O double complex salt is studied by X-ray diffraction. Crystallographic characteristics are as follows: a = 21.0335(5) ?, b = 8.0592(2) ?, c = 21.3452(5) ?, β = 91.254(1)°, V = 3617.43(15) ?³, P2₁/c space group, Z = 4, d _x = 2.714 g/cm³. Single-layer pseudohexagonal packing of complex anions is determined along the [−1 0 1] direction in the structure. Complex cations and crystallization water molecules are located between the mentioned layers.     

Deposition of NiO onto MoO3/γ-Al2O3 extrudates by slurry impregnation method

NiO-MoO₃/γ-Al₂O₃ catalysts were prepared by the reaction of γ-Al₂O₃ extrudates with an aqueous slurry of MoO₃, followed by the reaction of the MoO₃/γ-Al₂O₃ catalyst with an aqueous slurry of NiO, Ni(OH)₂, NiCO₃·2Ni(OH)₂·xH₂O, or 2NiCO₃·3Ni(OH)₂·4H₂O and by subsequent drying. The NiO deposition was examined with electron probe microanalysis. The deposited Ni efficiently increased the activity in benzothiophene hydrodesulfurization.     

Oxidative coupling of methane over Bi2O3?P2O5?K2O/Sm2O3

Oxidative coupling of methane over Bi₂O₃–P₂O₅–K₂O/Sm₂O₃ takes place giving more C₂H₄ as compared to C₂H₆. Sm₂O₃ supported Bi–P–K is a more active and selective catalyst, than TiO₂, -Al₂O₃, SiO₂ and MgO supported catalysts.

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Bi₂O₃–P₂O₅–K₂O/Sm₂O₃ , . Bi–P–K, Sm₂O₃, , TiO₂, -Al₂O₃, SiO₂, MgO.

     

Synthesis and structural characterisation of the palladium N-heterocyclic carbene cluster complexes [Pd3(μ-CO)3(NHC)3] and [Pd3(μ-SO2)3(NHC)3]

The reduction of trans-[Pd(NHC)₂Cl₂] (NHC = IMes, 1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene; IⁱPr₂ = 1,3-bis-isopropylimidazol-2-ylidene) with potassium graphite under an atmosphere of CO affords the palladium NHC carbonyl clusters [Pd₃(μ-CO)₃(NHC)₃] (NHC = IMes, 1; IⁱPr₂, 3). Treatment of 1 with SO₂ at room temperature yields the bridging SO₂ complex [Pd₃(μ-SO₂)₃(IMes)₃] (4) in quantitative yield. Complexes 1, 3 and 4 have been structurally characterised by X-ray crystallography.     

The crystal structure of Yb2(SO4)3·3H2O and its decomposition product, β-Yb2(SO4)3

Yb₂(SO₄)₃·3H₂O, synthesised by hydrothermal methods at 220(2) °C, has been investigated by single crystal X-ray diffraction. Yb₂(SO₄)₃·3H₂O crystallises in space group Cmc2₁ and is isostructural with Lu₂(SO₄)₃·3H₂O. The crystal structure has been refined to R₁=0.0145 for 3412 reflections [F_o>3σ(F)], and 0.0150 for all 3472 reflections. The structure of Yb₂(SO₄)₃·3H₂O is a complex framework of YbO₆ octahedra, YbO₈ and YbO₅(H₂O)₃ polyhedra and SO₄ tetrahedra. Thermal data shows that Yb₂(SO₄)₃·3H₂O decomposes between 120 and 190 °C to form β-Yb₂(SO₄)₃. The structure of a twinned crystal of β-Yb₂(SO₄)₃ was solved and refined using an amplimode refinement in R3c with an R₁=0.0755 for 8944 reflections [F_o>3σ(F)], and 0.1483 for all 16,361 reflections. β-Yb₂(SO₄)₃ has a unique structural topology based on a 3D network of pinwheels.     

Dehydrogenation of Isobutane Over V2O5/γ-Al2O3 Catalyst

The effect of the type of the support and the amount of V₂O₅ loading on the activity of V₂O₅/γ-Al₂O₃ catalyst for the dehydrogenation of isobutane have been investigated. Based on the experimental results of TPR, XRD and ESR spectroscopy, it is suggested that there are strong interactions between vanadia and carrier and that the V⁴⁺ species on the surface is the active site of V₂O₅/γ-Al₂O₃ for this reaction. This revised version was published online in June 2006 with corrections to the Cover Date.     

Kinetics of the radical reactions in pulse radiolyzed RHF — CO2(SF6)-O2-NO gaseous mixtures; RHF = CH3CH2F, CH3CHF2, CH3CF3, CH2FCF3

The kinetics of the peroxy radicals RHFO₂ reactions with NO has been studied by using pulse radiolysis and UV absorption spectroscopy. The rate constants of interaction of oxygen atoms with NO − k ₂ = 2.2±0.2·10⁻¹² cm³·s⁻¹ and NO₂ − k ₃ = 2.1±0.2·10⁻¹¹ cm³·s⁻¹ were found in agreement with the literature values. The bath gases (SF₆ or CO₂) have got minor effect on the rate constants of RHFO₂+NO→NO₂+prod. reactions; RHFO₂ = CH₃CH₂O₂, CH₃CHFO₂, CH₃CF₂O₂, CF₃CH₂O₂, CF₃CHFO₂. The obtained rate coefficients are in the scope of the literature values, although they are lower than those recommended in NIST database. The reasons are discussed.     

L-丙氨酸在LiNO3, NaNO3, KNO3和NaClO4水溶液中的体积性质

利用Anton Paar DMA 55精密数字密度计测定了L-丙氨酸在LiNO₃, NaNO₃, KNO₃和NaClO₄水溶液中的密度, 计算了L-丙氨酸的表观摩尔体积、极限偏摩尔体积、迁移偏摩尔体积、理论水化数和体积作用系数. 根据静电相互作用和结构水合作用模型讨论了阴离子和阳离子对迁移偏摩尔体积的影响. 结果表明, L-丙氨酸在四种含氧酸盐水溶液中的迁移体积均为正值, 并且随着盐浓度的增大而增大. L-丙氨酸两性离子端基和阴阳离子间的静电作用对迁移体积的贡献是主要的. 静电作用削弱了两性离子带电中心对周围水分子的电致收缩效应, 造成了理论水化数随溶液浓度的增加而减小. L-丙氨酸在NaNO₃, KNO₃和NaClO₄水溶液中迁移体积的不同主要是由于静电作用的不同引起的, 在LiNO₃水溶液中迁移体积的“反常”是由于结构相互作用的影响较大所致.     

Unusual ion UO4? formed upon collision induced dissociation of [UO2(NO3)3]?, [UO2(ClO4)3]?, [UO2(CH3COO)3]? ions

The following ions [UO₂(NO₃)₃]⁻, [UO₂(ClO₄)₃]⁻, [UO₂(CH₃COO)₃]⁻ were generated from respective salts (UO₂(NO₃)₂, UO₂(ClO₄)₃, UO₂(CH3COO)2) by laser desorption/ionization (LDI). Collision induced dissociation of the ions has led, among others, to the formation of UO₄ ⁻ ion (m/z 302). The undertaken quantum mechanical calculations showed this ion is most likely to possess square planar geometry as suggested by MP2 results or strongly deformed geometry in between tetrahedral and square planar as indicated by DFT results. Interestingly, geometrical parameters and analysis of electron density suggest it is an U^VI compound, in which oxygen atoms bear unpaired electron and negative charge.     

Ammoxidation of 3- and 4-picolines over V2O5?SnO2/γ?Al2O3 catalyst

The ammoxidation of 3- and 4-picolines has been studied over V₂O₅–SnO₂/–Al₂O₃ catalysts prepared by surface impregnation technique. Best results were obtained for the generation of cyanopyridines in the temperature range 400–450°C and sub-stoichiometric value with respect to O₂. Catalysts that were calcined above 700°C showed no activity.

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3- 4- V₂O₅–SnO₂/–Al₂O₃, . 400–450°C O₂. , 700 K, .

     

MoO3/Al2O3催化氧化选择性合成亚砜

采用浸渍法制备了不同负载量的MoO3/Al2O3催化剂,讨论了MoO3,Al2O3和MoO3/Al2O3负载的催化剂作用下,利用H2O2进行硫醚氧化制亚砜的反应.结果显示MoO3/Al2O3催化剂负载量为20%时催化活性最高,原料转化率达100%,且没有副产物生成.将该方法应用到兰索拉唑前体的氧化反应中,收率达到80%.催化剂重复使用6次不失活.     

[CH3NH3][NH3(CH2)6NH3]H3[P2Mo2W16O62]·H2O的水热合成与表征

首次合成了[CH3NH3][NH3(CH2)6NH3]H3[P2Mo2W16O62]·H2O,通过元素分析、红外光谱和X射线单晶衍射对合成产物进行了表征,并用TGA-DSC研究了化合物的热稳定性.晶体属单斜晶系,P21/m空间群,a=1.2596(3)nm,b=1.8715(4)nm,c=1.9816(4)nm,α=γ=90°,β=90.16(3)°,V=4.671(2)nm3,Z=2,Mr=4358.66,Dc=3.100g·cm-3,μ=19.978mm-1,F(000)=3792,R=0.0835,Rw=0.2026.结果表明,在晶体结构内形成了0.7364nm×0.8354nm的微孔.     

Some complexes containing Pt-C5-Co3 fragments: Molecular structure of trans-Pt{CCCC-μ3-C[Co3(μ-dppm)(CO)6(PPh3)]}2(PPh3)2 determined using synchrotron radiation

Reactions of platinum(II) chloro-phosphine complexes with Co₃(μ₃-CCCCCSiMe₃)(μ-dppm)(CO)₇ in the presence of NaOMe have given the compounds Pt{CCCC-μ₃-C[Co₃(μ-dppm)(CO)₇]}₂(dppe) (1), trans-Pt{CCCC-μ₃-C[Co₃(μ-dppm)(CO)₇]}₂(PEt₃)₂ (2) and trans-Pt{CCCC-μ₃-C[Co₃(μ-dppm) (CO)₆(PPh₃)]}₂(PPh₃)₂ (3), each of which contains two Co₃ clusters linked by C₅ chains to the Pt centre. Electrochemical studies (CVs) show the presence of both oxidation and reduction processes, the latter probably occurring on the CCo₃ cores. Ready reductive elimination of {Co₃(μ-dppm)(CO)₇}₂(μ₃:μ₃-C₁₀) occurs from 1 upon heating. The X-ray study of 3 was carried out using synchrotron radiation (Advanced Photon Source, Argonne, IL) to confirm its structure.