Regioselective germylcupration of acetylenes

The reaction of terminal acetylenes with (Ph₃Ge)₂Cu(CN)Li₂ (1) or (Et₃Ge)₂Cu(SMe₂)Li (2) provides vinylgermanes in good yields. Whereas germylcupration of 1-dodecyne gives 2-germyl-1-dodecene as a main product, germylmetalation of phenylacetylene or 3-methyl-3-buten-1-yne affords 1-germyl compounds preferentially.     

Synthesis of Functionalized Vinylgermanes through a New Ruthenium‐Catalyzed Coupling Reaction

Vinyl‐substituted germanes react stereo‐ and regioselectively with olefins in the presence of complexes containing Ru? H and Ru? Ge bonds with the formation of functionalized vinylgermanes that cannot be synthesized by olefin cross‐metathesis procedures. The reaction opens a new catalytic route for preparation of a class of organogermanes that are potent organometallic reagents for organic synthesis because they show very low toxicity and could replace organotin compounds. The mechanism of this new catalytic route was proven to involve an interesting insertion of the vinylgermane into the Ru? H bond and β‐Ge transfer to the metal with elimination of ethylene and generation of an Ru? Ge bond, followed by insertion of the alkene into the Ru? Ge bond and β‐H transfer to the metal to eliminate the substituted vinylgermane.     

Synthesis of tetrazoles,triazoles, and imidazolines catalyzed by magnetic silica spheres grafted acid

The magnetically separable catalysts are used in the synthesis of N-containing heterocycles, including tetrazoles, triazoles, and imidazolines. The magnetic silica sphere grafted sulfonic acid (MSS-SO₃H) is suitable for the synthesis of 1,2,3-triazole via the cycloaddition of nitroalkene with NaN₃, whereas the zinc-modified silica sphere catalyst (MSS-SO₃Zn) is more suitable for the synthesis of tetrazoles. The MSS-SO₃Zn catalyst also works well for the synthesis of 2-substituted imidazoline via the condensation of nitriles with ethylenediamine. Both of the MSS-SO₃H and MSS-SO₃Zn catalysts can be recovered easily by a magnet, and they can be reused without further tedious activation.     

以一种新型Gemini表面活性剂作为介孔模板剂通过转晶过程合成介孔ZSM-5分子筛

将一种新型Gemini表面活性剂,丙撑基双(十八烷基二甲基氯化铵)[C18H37(CH3)2–N+–(CH2)3–N+–(CH3)2C18H37]Cl2(C18-3-18),作为介孔模板剂用于水热法合成介孔ZSM-5分子筛.结果表明,在130 oC低温晶化即可高效合成介孔ZSM-5分子刷.C18-3-18的加入量可影响到所合成介孔ZSM-5分子筛的相对结晶度和织构性质,它的形成遵从一个转晶过程.在合成初期,凝胶中介孔模板剂C18-3-18的使用导向了介孔材料的生成;随后在TPABr的模板作用下,介孔材料慢慢转晶生成具有MFI结构的介孔ZSM-5;然后所合成的介孔ZSM-5晶粒进一步长大并聚集形成块状颗粒,同时产生晶间介孔.C18-3-18作为介孔导向剂不仅可用于合成介孔ZSM-5分子筛,也可用于其它介孔分子筛的合成中.     

Synthesis of functionalized vinylgermanes through a new ruthenium-catalyzed coupling reaction

Vinyl-substituted germanes react stereo- and regioselectively with olefins in the presence of complexes containing Ru-H and Ru-Ge bonds with the formation of functionalized vinylgermanes that cannot be synthesized by olefin cross-metathesis procedures. The reaction opens a new catalytic route for preparation of a class of organogermanes that are potent organometallic reagents for organic synthesis because they show very low toxicity and could replace organotin compounds. The mechanism of this new catalytic route was proven to involve an interesting insertion of the vinylgermane into the Ru-H bond and beta-Ge transfer to the metal with elimination of ethylene and generation of an Ru-Ge bond, followed by insertion of the alkene into the Ru-Ge bond and beta-H transfer to the metal to eliminate the substituted vinylgermane.     

Keplerate巨型纳米多孔聚氧钼酸盐作为可重复使用催化剂用于合成1,2,4,5-四取代咪唑(英文)

The Keplerate‐type giant nanoporous isopolyoxomolybdate (NH4)42[MoVI72MoV60O372‐(CH3COO)30(H2O)72], denoted {Mo132}, has been used as a catalyst for the synthesis of1,2,4,5‐tetrasubstituted imidazoles by the one‐pot, four‐component thermal reaction of benzil with aromatic aldehydes, primary amines, and ammonium acetate under solvent‐free conditions. The catalyst was prepared according to a previously published literature procedure using inexpensive and readily available starting materials, and subsequently characterized by FT‐IR, UV and X‐ray diffraction spectroscopy, as well as microanalysis. The results showed that {Mo132} exhibited high catalytic activity towards the synthesis of 1,2,4,5‐tetrasubstituted imidazoles, with the desired products being formed in good to high yields. Furthermore, the catalyst was recyclable and could be reused at least three times without any discernible loss in its catalytic activity. Overall, this new catalytic method for the synthesis of 1,2,4,5‐tetrasubstituted imidazoles provides rapid access to the desired compounds following a simple work‐up procedure, and avoids the use of harmful organic solvents. This method therefore represents a significant improvement over the methods currently available for the synthesis of tetrasubstituted imidazoles.     

Intermetallic Electride Catalyst as a Platform for Ammonia Synthesis

Electrides loaded with transition‐metal (TM) nanoparticles have recently attracted attention as emerging materials for catalytic NH₃ synthesis. However, they suffer from disadvantages associated with the growth and aggregation of nanoparticles. TM‐containing intermetallic electrides appear to be promising catalysts with the advantages of both electrides and transition metals in a single phase. LaRuSi is reported here to be an intermetallic electride with superior activity for NH₃ synthesis, and direct evidence is provided supporting its electride‐character‐induced catalytic performance. The discussion is made mainly based on the contrasting synthesis rates over the isostructural compounds LaRuSi, CaRuSi, and LaRu₂Si₂, and the N₂ isotope‐exchange reactions over these compounds. Lattice hydride ions, which can reversibly exchange with anionic electrons, are shown to be indispensable in the promotion of NH_x formation. The mechanism derived from the present findings provides new guidelines for NH₃ synthesis.     

TiO2一维纳米材料及其纳米结构的合成

本文对合成TiO₂一维纳米材料及其有序纳米阵列的阳极氧化法、模板法以及水热法进行了全面而系统的评述，着重介绍了它们的最新研究进展。阳极氧化法能制备牢固负载于基体上的TiO₂纳米管阵列，这有助于构筑TiO₂纳米结构及其在纳米器件上的应用；与多种制备技术如溶胶－凝胶工艺、电化学沉积以及原子层沉积等相结合，模板法可以合成出多种形貌的TiO₂纳米材料如纳米管、纳米线和纳米棒，并可以通过改变所用模板的微观尺寸来调控TiO₂一维纳米材料及其有序阵列的微结构参数；水热合成法可以制备出直径小且比表面积大的TiO2纳米管粉末。但从目前看来，该法还不能制备出牢固负载于基体上的有序纳米阵列。文章最后指出了TiO₂一维纳米材料及其有序纳米阵列合成中存在的问题及今后发展方向。     

Strategies for the synthesis of chiral, bidentate bis(perfluoroorganyl)phosphane ligands

Chiral, bidentate phosphane ligands, so-called PP ligands, are most frequently synthesized by reacting chiral ditosylates with diarylphosphanide ions.To use the P(CF₃)₂⁻ ion in nucleophilic substitution reactions, it is necessary to reduce the negative hyperconjugation, which is associated with a C-F activation. For this reason we synthesized different bis(trifluoromethyl)phosphanido complexes of mercury, silver and tungsten and investigated their use in nucleophilic substitution reactions. The most reactive compound, resulting from this study so far, is the pentacarbonylbis(trifluoromethyl)phosphanidotungstenate, [W{P(CF₃)₂}(CO)₅]⁻, which exhibits nearly the same bonding situation for the P(CF₃)₂ unit as in the free P(CF₃)₂⁻ ion. For use in synthesis of bis(trifluoromethyl)phosphane derivatives, Lewis acids are desirable, which stabilize the P(CF₃)₂⁻ ion by an intermediary formation of a donor acceptor adduct and can be split off after the synthesis of bis(trifluoromethyl)phosphane derivatives, as could be achieved using the extremely weak Lewis acids, CS₂ and acetone. These results could be established in the synthesis of the first example of an chiral, bidentate bis(trifluoromethyl)phosphane derivative.To synthesize a chiral, bidentate bis(pentafluorophenyl)phosphane derivative, a different synthetic strategy is necessary that does not involve the P(C₆F₅)₂⁻ ion, which decomposes even at low temperature. The implementation of functional P(CN)₂⁻ ions leads to the synthesis of functional, chiral bidentate dicyanophosphane derivatives which finally can be transformed into the corresponding bis(pentafluorophenyl)phosphane derivatives.     

Integration of Nine Steps into One Membrane Reactor To Produce Synthesis Gases for Ammonia and Liquid Fuel

The synthesis of ammonia and liquid fuel are two important chemical processes in which most of the energy is consumed in the production of H₂/N₂ and H₂/CO synthesis gases from natural gas (methane). Here, we report a membrane reactor with a mixed ionic‐electronic conducting membrane, in which the nine steps for the production of the two types of synthesis gases are shortened to one step by using water, air, and methane as feeds. In the membrane reactor, there is no direct CO₂ emission and no CO or H₂S present in the ammonia synthesis gas. The energy consumption for the production of the two synthesis gases can be reduced by 63 % by using this membrane reactor. This promising membrane reactor process has been successfully demonstrated by experiment.     

Tunable and rapid crystallisation of phase pure Bi2MoO6 (koechlinite) and Bi2Mo3O12 via continuous hydrothermal synthesis

Herein, we report the rapid single step hydrothermal synthesis of phase pure Bi₂MoO₆ (koechlinite) and Bi₂Mo₃O₁₂, via a continuous hydrothermal flow synthesis (CHFS) reactor, which uses supercritical water of 375–450 °C at a pressure of 24.1 MPa as a crystallising medium. The product being obtained as highly crystalline nano-materials with high surface area. Simple variation in synthesis condition and appropriate solution stoichiometry were shown to be sufficient to select the phase of the product. The materials synthesised showed significant photcatalytic activity towards the decolourisation of methylene blue in comparison to a commercial gold standard photocatalyst.     

Fuzzy model prediction of Co (III)Al2O3 catalytic behavior in Fischer-Tropsch synthesis

The application of Co(Ⅲ)/Al2O3 catalyst in Fischer-Tropsch synthesis(FTS)was studied in a wide range of synthesis gas conversions and compared with Fuzzy Simulation results.Present study applies fuzzy model to predicting the product composition of CH4,CO2 and CO in Fischer-Tropsch process for natural gas synthesis,in which the input vector was 4-dimension including four variables(operating pressure, operating temperature,time and CO/H2 ratio)of 70 different experiments and the output product is a composition of CO2,CO and CH4. The Mamdani algorithm has been applied to the training of the fuzzy system and the test set was used to evaluate the performance of the system including R2,ARE,AARE and SD.The results demonstrated that the predicted values from the model were in good consistency with the experimental data.The work indicates how fuzzy inference system(FIS),as a promising predicting technique,would be effectively used in FTS.     

Zeta potential of shape-controlled TiO2 nanoparticles with surfactants

Zeta potential of shape- and size-controlled TiO₂ nanoparticles obtained with the introduction of surfactants during synthesis was measured at different pH values. A unique finding is that TiO₂ nanoparticles shaped by sodium dodecyl sulfate (SDS) have double isoelectric points (IEPs), while other shape-controlled TiO₂ nanoparticles have only one IEP. The double IEPs might be due to the complex chemistry of TiO₂ nanoparticles with the presence of impurities (Na, S, C, etc.). At neutral pH, shape- and size-controlled TiO₂ nanoparticles have more negative zeta potential values and lower IEPs than TiO₂ nanoparticles obtained without the addition of surfactants during synthesis and the commercial anatase TiO₂ nanoparticles Degussa P-25. The lower IEPs could be attributed to the presence of carbonates on particle surfaces. The IEP value of TiO₂ nanoparticles increases with an increase in calcination temperature. The results suggest that the zeta potential of TiO₂ nanoparticles can be manipulated with the addition of surfactants during the synthesis process.     

Mechanistic Insights into a Sustainable Mechanochemical Synthesis of Ettringite

Mechanochemistry offers an environmentally benign and facile synthesis method for a variety of cement paste constituents. In addition, these methods can be used to selectively tune the properties of cement components. The mineral ettringite is an important component of cementitious materials and has additional technological potential due to its ion exchange properties. Synthesis of ettringite via mechanochemistry is an environmentally friendly alternative to conventional wet-chemical synthesis established in industry. This contribution explores the mechanism of a two-step mechanochemical synthesis of ettringite, which was previously found to greatly improve the reaction conversion as compared with one-pot synthesis. The crystallinity of Al(OH)₃ was found to decrease during the first stage of this mechanochemical synthesis. This was correlated to a significant decrease in the particle size of Al(OH)₃ in this stage. No other significant changes were found for the other components, suggesting that mechanochemical activation of Al(OH)₃ is responsible for the enhanced formation of ettringite by the two-step approach. The environmentally friendly approach developed for ettringite synthesis offers a versatile synthetic strategy, which can be applied to synthesise further cementitious materials.     

Recent developments in the utility of Zn(L-proline)2 as benign and recyclable metallo-organocatalyst in organic synthesis

The coordination of Zn (II) with L - proline as a choral ligand makes the initiated complex Zn(L-proline)₂ a moderately soft Lewis acid. Recently Zn(L-proline)₂ has emerged as a promising reusable chiral catalyst which could be utilized in a diversity of transformations. The present short review article focuses mainly on recent developments in utility of Zn(L-proline)₂ in organic synthesis. This includes Aldol condensation, synthesis of heterocyclic compounds with five, six and fused rings.     

Cuprous oxide nanospheres as probes for light scattering imaging analysis of live cells and for conformation identification of proteins

A facile solution-phase synthesis route of highly uniform Cu₂O nanospheres (Cu₂O NPs) with the size of 57.7 ± 4.7 nm was developed, and then the nanoparticles were applied to live cell imaging under a common dark-field microscope. Starting from copper(II) salts, the synthesis of Cu₂O NPs was made in the presence of cetyltrimethylammonium bromide (CTAB) by reducing the copper(II) with sodium borohydride (NaBH₄) in aqueous medium and by aging process in the air. Monitoring of morphology evolution process of Cu₂O NPs with scanning electron microscopy (SEM) and measuring of the UV-visible spectra showed that the synthesis of Cu₂O NPs follows the reduction-oxidation coupled process of Cu²⁺ into Cu⁰ species at first and then the resulted Cu⁰ species into Cu₂O NPs in the air. Light scattering (LS) features have been measured with a common spectrofluorometer and a common dark-field microscope, and it was found that the as-prepared Cu₂O NPs display strong blue scattering light and can be applied for cell imaging. If incubated with human bone marrow neuroblastoma, transferrin-conjugated Cu₂O NPs can get into the cells and show strong pure blue light in cytoplasm. Further investigations showed that the Cu₂O NPs could be applied for probes for conformation of proteins.     

Electrochemical synthesis of coatings in the system Ti-Si-B from molten salts

Powder and coatings of metal-like refractory compounds (MLRC) can be produced by electrochemical synthesis from molten salts. The stoichiometry of the deposited MLRC was found to correlate with the molar ratio of MLRC component ions in the melts. The system Ti-Si-B is of particular interest in terms of electrochemical synthesis since the titanium, silicon and boron potentials in the melt are close together. The electrochemical synthesis has been investigated in the system NaCl-KCl-NaF-K₂TiF₆-K₂SiF₆-KBF₄ at 700°C. The opportunity of deposition of new ternary compound in the system Ti-Si-B is shown by the electrochemical synthesis from molten salts.     

Bildung Siliciumorganischer Verbindungen. XXXXV. Die Synthese von 1,3,3,5,5,8,8-Heptamethyl-1,3,5,8-tetrasila-bicyclo-[2,2,2]-octan

We report the synthesis of (a), which is finally formed by the reaction of (b) with CHBr₃ and Li. (b) can be obtained from (c) by a cleavage with Br₂ and yields (d) with LiAlR₄. The synthesis of (c) is described. (a) is a very stable crystalline compound, m.p. 55–56°C.     

Nonequilibrium plasma-chemical synthesis of nanosized particles of metal oxides

The results of investigation into the synthesis conditions and basic characteristics of nanoparticles of titanium dioxide and the mixed oxide (TiO₂)_x(SiO₂)_1?x from a gaseous mixture of oxygen, hydrogen, and titanium tetrachloride (or a mixture of titanium and silicon tetrachlorides) are reported. The synthesis was initiated by a pulsed electron beam and was a chain process in character. The geometric dimensions of oxide particles were measured and their X-ray diffraction, X-ray fluorescence, and IR spectrometric studies were performed. It was shown that the nonequilibrium character of the synthesis process induced by a pulsed electron beam allowed the temperature threshold for the formation of the crystalline structure of particles to be lowered.     

The mechanochemical Friedel-Crafts polymerization as a solvent-free cross-linking approach toward microporous polymers

Herein we report the mechanochemical Friedel-Crafts alkylation of 1,3,5-triphenylbenzene (TPB) with two organochloride cross-linking agents, dichloromethane (DCM) and chloroform (CHCl₃), respectively. During a thorough milling parameter evaluation, the DCM-linked polymers were found to be flexible and extremely sensitive toward parameter changes, which even enables the synthesis of a polymer with a SSA_BET of 1670 m²/g, on par with the solution-based reference. Contrary, CHCl₃-linked polymers are exhibiting a rigid structure, with a high porosity that is widely unaffected by parameter changes. As a result, a polymer with a SSA_BET of 1280 m²/g could be generated in as little as 30 minutes, outperforming the reported literature analogue in terms of synthesis time and SSA_BET. To underline the environmental benefits of our fast and solvent-free synthesis approach, the green metrics are discussed, revealing an enhancement of the mass intensity, mass productivity and the E-factor, as well as of synthesis time and the work-up in comparison to the classical synthesis. Therefore, the mechanochemical polymerization is presented as a versatile tool, enabling the generation of highly porous polymers within short reaction times, with a minimal use of chlorinated cross-linker and with the possibility of a post polymerization modification.