Synthesis of Phosphonodithioate,Oxathiaphosphinin, Oxathiaphosphole,and Dithiaphosphole Derivatives from the Reaction of Lawesson's Reagent with Phenolic Mannich Bases and Oxime Derivatives

The reaction of Lawesson's reagent 1a, with niclosamide 2 proceeded by thionation and formation of carbothioamide 3 and the zwitterionic oxathiaphosphinin 4a. LR reacted with 8-hydroxyquinoline (5), 2-methylquinoline-4-ol (7), and β-naphthol (9) to give the phosphonodithioates 6, 8, or 10. The reaction of LR with the Mannich bases 11 and 14 afforded the oxathiaphosphinins 13 and 15, whereas the phosphonodithioates 17 and 19 were isolated in the case of Mannich bases 16 and 18. LR reacted with phthalimide Mannich base 20 to give the dithione 21 and N-methylphthalimide (22). Reaction of ketone monoxime 23 with LR resulted in the formation of the oxathiaphosphole 24 and the dithiaphosphole 25, whereas the monoxime 26 afforded the thioxoethanone thioxime 27. Ketone dioximes 28 and 34 afforded the phosphonodithioates 29 and 36, respectively, when they were allowed to react with LR, whereas the dioxime 30 gave compounds 32 and 33. Moreover, the molluscicidal potency of the newly synthesized compounds against Biomphalaria glabrata snails was studied, too.     

A new, efficient and simple method for the thionation of ketones to thioketones using P4S10/Al2O3

A simple, efficient and new method has been developed for the synthesis of thioketones by thionation of ketones using P₄S₁₀/Al₂O₃ in acetonitrile. It has been found that the P₄S₁₀/Al₂O₃ combination provides a simple and convenient method for the synthesis of thioketones.     

Decomposition of P2S2N4(Si(CH3)3)4A12C14 as Studied by FT-Raman and Quantum Chemistry Means

The dimeric title compound decomposes upon heating to give the monomer and desulphurized monomer as shown by FT-Raman and quantum chemical means.     

Highly Efficient Etherification and Oxidation of Aromatic Alcohols Using Supported and Unsupported Phosphorus Pentoxide as a Heterogeneous Reagent

A highly efficient procedure for etherification and oxidation of aromatic alcohol is described using unsupported and supported P₂O₅ on alumina and/or silica gel. The silica gel and alumina proved to be the most suitable support among the supports examined in our experiments. It was illustrated that the etherification and oxidative performance in reactions depend largely upon variables including reaction temperature, the nature of the P₂O₅ used (supported or unsupported P₂O₅), and whether solvent-free conditions are applied. It was shown that P₂O₅ not only can convert the aromatic alcohols into corresponding ethers and/or aldehyde and ketone but also can convert aromatic ethers into aldehyde or ketone via oxidative cleavage. Finally, quantum mechanical calculations were performed to rationalized these events, and it was indicated that aldehyde and ketone are more favorable products on the basis of the heat of formation (ΔH_f).

KF/Al2O3: Solid-Supported Reagent Used in 1,3-Dipolar Cycloaddition Reaction of Nitrile Oxide

The stereoselective synthesis of 2-isoxazolidine through 1,3-dipolar cycloaddition reaction of nitrile oxide, which is in situ generation from aldoxime in the presence of N-bromosuccinamide and solid-supported reagent KF/Al₂O₃ at room temperature, is reported. KF/Al₂O₃ is sufficiently basic such that it can replace organic bases such as Et₃N used in typical procedures and it catalyses the reaction to enhance the rate of the reaction.     

SPIN-CROSSOVER OF [Fe(Cl-BZIMPY)2](ClO4)2 INDUCED BY DEPROTONATION

Abstract

The ligand 4-Cl-2,6-bis(benzimidazol-2′-yl)-pyridine(Cl-bzimpy;H₂L) acts as a bidentate when coordinated with transition metal ions and the complex [Fe(Cl-bzimpy)₂](ClO₄)₂ was isolated as a solid. The protonation constants (logK). The free ligand and the complex were evaluated in 30:70 (v/v) H₂O:EtOH at room temperature and ionic strength of 0.13M (KCl). Coordination of the ligand to the metal ion leads to an increase of the acidity of the imino-hydrogen of the benzimidazole group. Deprotonation leads to a change in the spin-state (to the low-spin state; HS → LS transition) of the complex associated with a decrease in the spin-crossover equilibrium constant (K_sc). An opposite shift of spin-state is observed when HClO₄ is added to the complex solution, thus showing the reversibility of the process.     

Supramolecular aggregation in new crystals with nonlinear optical properties: 2-aminophenol-HClO4, 3-aminophenol-HClO4 and 4-aminophenol-HClO4

Three new hybrid crystals of 2-aminophenol-HClO₄ (2-AP-HClO₄, 1), 3-aminophenol-HClO₄ (3-AP-HClO₄, 2) and 4-aminophenol-HClO₄ (4-AP-HClO₄, 3) were obtained and their crystal structures determined. The 1 crystallises in centrosymmetric space group C2/c of monoclinic system while the other two (2 and 3) crystallise in the non-centro symmetric space group P2₁ and P2₁2₁2₁, respectively. The oppositely charged units of the crystals, i.e. positively charged 2-APH⁺, 3-APH⁺ and 4-APH⁺ and ClO₄⁻, interact via weak N⁺–HO and O–HO hydrogen bonds forming 3D-supramolecular network. Relative to KDP the SHG efficiencies are 0.62 for 2 and 0.33 for 3, measured at 1064 nm using the Kurtz–Perry method.     

Reaction of Vinylpyridines with Active Modifications of Elemental Phosphorus in KOH/DMSO

The phosphorylation of 2-vinyl- and 4-vinylpyridines by white phosphorus and active modifications of red phosphorus (obtained by thermal polymerization of white phosphorus in the presence of graphite or the action of ionizing radiation in benzene) in the KOH/DMSO superbase system at room temperature leads to the formation of tris[2-(2-pyridyl)ethyl]- and tris[2-(4-pyridyl)ethyl]phosphine oxides in 58-72% yield. These oxides are promising ligands for design of metal complex catalysts. These vinylpyridines react less efficiently with ordinary red phosphorus and the yield of the corresponding tris(2-pyridylethyl)phosphine oxides does not exceed 10%.     

Insights into photoluminescence property and photocatalytic activity of cubic and rhombohedral ZnIn2S4

Cubic and rhombohedral ZnIn₂S₄ were synthesized by thermal sulfidation of Zn-In mixed oxide precursor in H₂S atmosphere at different temperatures. Cubic ZnIn₂S₄ was obtained when Zn-In mixed oxide precursor was sulfurized at 400 °C. With sulfidation temperature increasing from 400 to 800 °C, the crystal phase of ZnIn₂S₄ gradually turned from cubic to rhombohedral, which was demonstrated by different analysis techniques such as XRD, Raman, SEM, etc. UV-vis absorption spectra indicated that cubic ZnIn₂S₄ displayed better light absorption property than rhombohedral ZnIn₂S₄, with band gaps calculated to be 2.0 and 2.5 eV, respectively. However, under visible light irradiation, rhombohedral ZnIn₂S₄ photocatalyzed H₂ evolution from aqueous sodium sulfite/sulfide solution efficiently, whereas cubic ZnIn₂S₄ was not active for this reaction. The photoluminescence property revealed the different dynamics of photogenerated carriers, which made a predominant contribution to the increasing photocatalytic performances of ZnIn₂S₄ with crystal phase turning from cubic to rhombohedral.     

An efficient synthetic route to substituted tetrahydropyrimidines by Cu(OTf)2-mediated nucleophilic ring-opening followed by the [4+2] cycloaddition of N-tosylazetidines with nitriles

A highly efficient strategy for Cu(OTf)₂-mediated S_N2 type nucleophilic ring-opening followed by the [4+2] cycloaddition reactions of a number of 2-aryl-N-tosylazetidines with nitriles to afford a variety of substituted tetrahydropyrimidines in excellent yields is reported. The resulting tetrahydropyrimidines could easily be transformed into synthetically important 1,3-diamines by acid-catalyzed hydrolysis. The strategy has been extended to the synthesis of enantiomerically pure tetrahydropyrimidines from enantiopure disubstituted azetidines. The reaction proceeds through an S_N2 type mechanism as proposed by us earlier.     

磁场诱导下Fe3S4向FeS2转化速率的增加

以FeCl₃和CH₄N₂S为主要原料，在0.2～0.4 T的外加磁场强度下，温度为170 ℃的反应体系中研究了磁场对前驱物Fe₃S₄转化成FeS₂过程的影响。结果表明，Fe₃S₄到FeS₂的转化率是与磁场强度有关的。Fe₃S₄的硫化过程可能是通过溶解-再结晶机理。外加磁场的存在可以促进物质的传输过程，从而加速前驱物的溶解和再结晶过程，导致和没有外加磁场相比Fe₃S₄到FeS₂的转化率的增加。     

Na2S2O4 initiated free radical additions of polyfluoroalkyl halides to 4-pentenamides

The free radical additions of fluorine-containing halides to 4-pentenamides initiated by Na₂S₂O₄ were investigated. Both polyfluoroalkyl iodide and ethyl iododifluoroacetate, gave rise to fluorine-containing γ-butyrolactones as the main products while bromides such as ethyl bromodifluoroacetate gave the addition-reduction product. After steric and stereo effects on reaction yields were studied using various substrates, it was concluded that the reactions of 4-pentenamides and polyfluoroalkyl iodides provide one alternative approach to prepare γ-butyrolactones with fluorinated side chains.     

Ni/NiCo2O4电极的制备及其析氧反应性能

采用溶胶-凝胶法制备NiCo₂O₄尖晶石粉体, 然后以多孔Ni 为基体, 通过复合溶胶涂覆结合烧结制备Ni/NiCo₂O₄ 涂层电极. 运用扫描电子显微镜(SEM)、能量色散谱(EDS)和X 射线衍射(XRD)表征粉体以及Ni/NiCo₂O₄涂层电极的组成和结构. 采用循环伏安(CV), 稳态极化(LSV), 电化学阻抗谱(EIS), 恒电位阶跃以及恒电位长时间电解研究涂层电极在5 mol·L^-1 KOH溶液中的电催化析氧反应(OER). 结果表明: Ni/NiCo₂O₄涂层电极与多孔Ni 电极对比, 具有低的析氧过电位、高的比表面积和高的稳定性能; 其中比表面积增大了28.69倍,表观活化能在不同过电位分别降低了166.78和162.15 kJ·mol^-1.     

Surface Coordination of Pd/ZnIn2S4 toward Enhanced Photocatalytic Activity for Pyridine Denitrification

New surface coordination photocatalytic systems that are inspired by natural photosynthesis have significant potential to boost fuel denitrification. Despite this, the direct synthesis of efficient surface coordination photocatalysts remains a major challenge. Herein, it is verified that a coordination photocatalyst can be constructed by coupling Pd and CTAB-modified ZnIn₂S₄ semiconductors. The optimized Pd/ZnIn₂S₄ showed a superior degradation rate of 81% for fuel denitrification within 240 min, which was 2.25 times higher than that of ZnIn₂S₄. From the in situ FTIR and XPS spectra of 1% Pd/ZnIn₂S₄ before and after pyridine adsorption, we find that pyridine can be selectively adsorbed and form Zn⋅⋅⋅C-N or In⋅⋅⋅C-N on the surface of Pd/ZnIn₂S₄. Meanwhile, the superior electrical conductivity of Pd can be combined with ZnIn₂S₄ to promote photocatalytic denitrification. This work also explains the surface/interface coordination effect of metal/nanosheets at the molecular level, playing an important role in photocatalytic fuel denitrification.     

On the crystal chemistry of three copper(II)-arsenates: Cu3(AsO4)2-III,Na4Cu(AsO4)2, and KCu4(AsO4)3

The three copper(II)-arsenates were synthesized under hydrothermal conditions; their crystal structures were determined by single-crystal X-ray diffraction methods:Cu₃(AsO₄)₂-III:a=5.046(2) Å,b=5.417(2) Å,c=6.354(2) Å, =70.61(2)°, =86.52(2)°, =68.43(2)°,Z=1, space group ,R=0.035 for 1674 reflections with sin / 0.90 Å^–1.Na₄Cu(AsO₄)₂:a=4.882(2) Å,b=5.870(2) Å,c=6.958(3) Å, =98.51(2)°, =90.76(2)°, =105.97(2)°,Z=1, space group ,R=0.028 for 2157 reflections with sin / 0.90 Å^–1.KCu₄(AsO₄)₃:a=12.234(5) Å,b=12.438(5) Å,c=7.307(3) Å, =118.17(2)°,Z=4, space group C2/c,R=0.029 for 1896 reflections with sin / 0.80 Å^–1.Within these three compounds the Cu atoms are square planar [4], tetragonal pyramidal [4+1], and tetragonal bipyramidal [4+2] coordinated by O atoms; an exception is the Cu(2)^[4+1] atom in Cu₃(AsO₄)₂-III: the coordination polyhedron is a representative for the transition from a tetragonal pyramid towards a trigonal bipyramid. In KCu₄(AsO₄)₃ the Cu(1)^[4]O₄ square and the As(1)O₄ tetrahedron share a common O—O edge of 2.428(5) Å, resulting in distortions of both the CuO₄ square and the AsO₄ tetrahedron. The two Na atoms in Na₄Cu(AsO₄)₂ are [6] coordinated, the K atom in KCu₄(AsO₄)₃ is [8] coordinated by O atoms.Die drei Kupfer(II)-Arsenate wurden unter Hydrothermalbedingungen gezüchtet und ihre Kristallstrukturen mittels Einkristall-Röntgenbeugungsmethoden ermittelt:Cu₃(AsO₄)₂-III:a = 5.046(2) Å,b = 5.417(2) Å,c = 6.354(2) Å, = 70.61 (2)°, = 86.52(2)°, = 68.43(2)°,Z = 1, Raumgruppe ,R = 0.035 für 1674 Reflexe mit sin / 0.90 Å^–1.Na₄Cu(AsO₄)₂:a = 4.882(2) Å,b = 5.870(2) Å,c = 6.958(3) Å, = 98.51(2)°, = 90.76(2)°, = 105.97(2)°,Z = 1, Raumgruppe ,R = 0.028 für 2157 Reflexe mit sin / 0.90 Å^–1.KCu₄(AsO₄)₃:a = 12.234(5) Å,b = 12.438(5) Å,c = 7.307(3) Å, = 118.17(2)°,Z = 4, Raumgruppe C2/c,R = 0.029 für 1896 Reflexe mit sin / 0.80 Å^–1.Die Cu-Atome in diesen drei Verbindungen sind durch O-Atome quadratisch planar [4], tetragonal pyramidal [4 + 1] und tetragonal dipyramidal [4 + 2]-koordiniert; eine Ausnahme ist das Cu(2)^{[4 + 1]}-Atom in Cu₃(AsO₄)₂-III: Das Koordinationspolyeder stellt einen Vertreter des Übergangs von einer tetragonalen Pyramide zu einer trigonalen Dipyramide dar. In KCu₄(AsO₄)₃ haben das Cu(1)^[4]O₄-Quadrat und das As(1)O₄-Tetraeder eine gemeinsame O—O-Kante von 2.428(5) Å, was eine Verzerrung der beiden Koordinationsfiguren CuO₄-Quadrat und AsO₄-Tetraeder bedingt. Die zwei Na-Atome in Na₄Cu(AsO₄)₃ sind durch O-Atome [6]-koordiniert, das K-Atom in KCu₄(AsO₄)₃ ist [8]-koordiniert.

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Zur Kristallchemie dreier Kupfer (II)-Arsenate: Cu₃(AsO₄)₂-III, Na₄Cu(AsO₄)₂ und KCu₄(AsO₄)₃

     

Synthesis, characterization, thermal stability and electrochemical properties of poly-4-[(2-methylphenyl)iminomethyl]phenol

In this study, the reaction conditions of poly-4-[(2-methylphenyl)iminomethyl]phenol (P-2-MPIMP) were studied by using oxidants such as air O₂, H₂O₂ and NaOCl in an aqueous alkaline medium between 50 and 90 °C. The structures of the synthesized monomer and polymer were confirmed by FT-IR, UV-vis, NMR and elemental analysis. The characterization was made by TG-DTA, size exclusion chromatography (SEC) and solubility tests. At the optimum reaction conditions, the yield of poly-4-[(2-methylphenyl)iminomethyl]phenol (P-2-MPIMP) was found to be 20% (for air O₂ oxidant), 33% (for H₂O₂ oxidant), and 74% (for NaOCl oxidant). According to the SEC analysis, the number-average molecular weight (M_n), weight-average molecular weight (M_w) and polydispersity index (PDI) values of P-2-MPIMP were found to be 3300, 4100 g mol⁻¹ and 1.242, using H₂O₂, and 4550, 5150 g mol⁻¹and 1.132, using air O₂ and 5300, 5850 g mol⁻¹ and 1.104, using NaOCl, respectively. According to TG analysis, the weight losses of 4-[(2-methylphenyl)iminomethyl]phenol (2-MPIMP) and P-2-MPIMP were found to be between 75.29% and 48.17% at 1000 °C, respectively. P-2-MPIMP was shown to have a higher stability against thermal decomposition. Also, electrical conductivity of the P-2-MPIMP was measured, showing that the polymer is a typical semiconductor. Electrochemically, the highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO) and electrochemical energy gaps ( of 2-MPIMP and P-2-MPIMP were found to be −6.01, −6.03; −2.63, −2.82; 3.38 and 3.21 eV, respectively. According to UV-vis measurements, the optical band gap (E_g) of 2-MPIMP and P-2-MPIMP was found to be 3.40 and 2.97 eV, respectively.     

ZnIn_2S_4的制备及其表面活性剂辅助的形貌控制生长

采用湿化学合成路线以巯基乙酸为包覆剂,水为溶剂制备了六方相ZnIn2S4。应用能谱分析(EDS)、X射线衍射(XRD)、透射电镜(TEM)、扫描电镜(SEM)和紫外-可见光谱对产物的组成、结构、形貌和光学性质进行了表征。结果表明,所得到的ZnIn2S4具有层状形貌。这些层状物是由ZnIn2S4纳米粒子前驱体在热处理过程中聚集生长而成的。另外,以ZnIn2S4纳米粒子前驱体为起始原料,借助表面活性剂的导向作用在固/液界面成功地实现了ZnIn2S4的形貌控制生长,得到了具有棒状、棒簇状、管簇状形貌的ZnIn2S4。根据实验结果,初步讨论了可能的表面活性剂辅助的ZnIn2S4形貌控制生长的机制。     

DSC study of the phase transitions in [Ni(D2O)6](ClO4)2 and [Ni(H2O)6](ClO4)2

DSC measurements were carried out for [Ni(H₂O)₆](ClO₄)₂ (sampleH) and [Ni(D₂O)₆](ClO₄)₂ (sampleD) in the temperature range 300–380 K. For both compounds two anomalies on the DSC curves were detected. The results for sampleH are compared to those previously obtained using adiabatic calorimetry method. For both compounds studied in this work the high-temperature transition appears at the same temperature while the low-temperature one is shifted towards higher temperatures in sampleD. Disorder connected with H₂O or D₂O groups is suggested in the intermediate phase between the low- and high-temperature transitions.     

Ge4+、Sn4+掺杂尖晶石LiMn2O4的合成与电化学表征

使用Ge⁴⁺、Sn⁴⁺作为掺杂离子, 通过高温固相法制备四价阳离子掺杂改性的尖晶石LiMn₂O₄材料. X射线衍射(XRD)和扫描电子显微镜(SEM)分析表明, Ge⁴⁺离子取代尖晶石中Mn⁴⁺离子形成了LiMn_2-xGe_xO₄ (x=0.02,0.04, 0.06)固溶体; 而Sn⁴⁺离子则以SnO₂的形式存在于尖晶石LiMn₂O₄的颗粒表面. Ge⁴⁺离子掺入到尖晶石LiMn₂O₄材料中, 抑制了锂离子在尖晶石中的有序化排列, 提高了尖晶石LiMn₂O₄的结构稳定性; 而在尖晶石颗粒表面的SnO₂可以减少电解液中酸的含量, 抑制酸对LiMn₂O₄活性材料的侵蚀. 恒电流充放电测试表明, 两种离子改性后材料的容量保持率均有较大幅度的提升, 有利于促进尖晶石型LiMn₂O₄锂离子电池正极材料的商业化生产.