Bismuth (III) Triflate Catalyzed Multicomponent Synthesis of 2,4,5-Trisubstituted Imidazoles

Substituted imidazoles are of interest because of their useful biological activities. While several methods have been developed for the synthesis of such compounds, some of the reported methods utilize corrosive or toxic catalysts. We report a bismuth (III) triflate catalyzed multicomponent synthesis of 2,4,5-trisubstituted imidazoles. Bismuth (III) compounds are attractive from a green chemistry perspective because they are remarkably non-toxic and non-corrosive. Multicomponent syntheses save time and generate less waste.

Bismuth (III) Triflate Catalyzed Multicomponent Synthesis of 2,4,5-Trisubstituted Imidazoles

Substituted imidazoles are of interest because of their useful biological activities. While several methods have been developed for the synthesis of such compounds, some of the reported methods utilize corrosive or toxic catalysts. We report a bismuth (III) triflate catalyzed multicomponent synthesis of 2,4,5-trisubstituted imidazoles. Bismuth (III) compounds are attractive from a green chemistry perspective because they are remarkably non-toxic and non-corrosive. Multicomponent syntheses save time and generate less waste.

Syntheses，Structures and Properties of Some New Composition Perovskite Compounds：Sr0．6Bi0．4FeO2．7，Sr1－xBixFeO3－y and Ba1．5Pt0．5Mn2O6

New composition perovskite-type compounds with formula Sr0.6Bi0.4FeO2.7,Sr1-xBixFeO3-y(x=0.1 to 0. 9 in interveral of 0.1),and Ba1.5Pt0.5Mn2O6 have been synthsized and structurally characterized.The crystal structure of Sr0.6Bi0.4FeO2.7has been determined by X-ray single crystal diffraction,and the data of neutron powder diffraction collected at both room temperature and elevated temperature(380℃).The compound Sr0.6Bi0.4FeO2.7 crystallizes in the cubic space group of Pm3m with Z=1,a=3.9330(6) at room temperature,a=3.9498(6)A at 380℃.The magnetic structure from the neutron powder diffraction data collected at room temperature is consistent with a simple G-type antiferromagnetism and has a magnetic moment of 4.98 μB per Fe atom.The structures of Sr1-xBixFeO3-y with x other than 0.4 were also refined from the X-ray powder diffraction data.The data were consistent with a tetragonal cell when x=0.1,a rhombohedral cell when x= 0.9,and a cubic cell for x=0.2～0.8.From single crystal X-ray diffraction data,Ba1.5Pt0.5Mn2O6 crystallizes in hexagonal space group of P63mc with a= 5.7722 (6),c=4.4504(9),V=128.42(2),Z=1.The Sr(1-x)BixFeO(3-y)are found to be a good electronic and ionic conductor.

Synthesis of BiOCl photocatalyst by a low-cost,simple hydrolytic technique and its excellent photocatalytic activity

A novel photocatalyst, bismuth oxychloride （BiOC1） micro-nano particles with a fine ferrite plate structure, was prepared by a low-cost, simple hydrolytic method. The as-prepared BLOC1 was characterized by scanning electron microscopy （SEM）, thermogravimetric analysis-differential thermal analysis （TGA-DTA）, X-ray diffraction （XRD）, and UV-vis diffuse reflectance spectra （DRS）. The effects of preparation conditions such as sodium dodecyl benzene sulfonate （SDBS） dispersant, HC1 concentration, and heat treatment temperature on BiOC1 performances were investigated. Moreover, its photocatalytic activity was evaluated on the degradation of methylene orange （MO） and was compared with that of TiO2 （P25）. The experimental results confirmed that BiOC1 micro-nano particles prepared with SDBS, the HC1 concentration of 1.5 mol/L, and the heat treatment temperature of 80℃ exhibited the best performance for the photodegradation of MO solution, and they showed good stability and better photocatalytic activity than P25 photocatalyst.

Effect of Pb Content on Phase Composition and Property of Bi-Pb-Sr-Ca-Cu-O System Superconductors

The addition of Pb in the superconductors of BiSrCaCuO system is very helpful for growth of the high-Tc phase (Tc 110K). We prepared a series of samples with nominal composition of Bi2-xPbxSr2Ca2Cu3Oy (0.1&lex&le2). The zero resistance transition temperature Tc of 106K and the critical transport current density Jc of 1 × 103A/cm2 at 77K have been obtained for the samples of Bi2-xPbxSr2Ca2Cu3Oy (x=0.2 and 0.3). The X-ray diffraction analysis and measurement of AC magnetic susceptibility confirmed that the material is comprised of single high-Tc phase. We also report the magnetic properties of this material as well as the results of TEM observation.

Structures of Bi-Pb-Sr-Ca-Cu-O Superconductor with T_c of 108K

Have developed a Bi-Pb-Sr-Ca-Cu-O superconductor with an onset Tc of 108K and a zero resistance temperature Tco of 104K. There are at least five different phases: the high Tc and low Tc ones and three minor ones. The high Tc and low Tc phases have the face - centered orthorhombic structure with a = 0.540nm, b = 0.545nm, c = 3.669nm and a = 0.540nm b = 0.546nm, c = 3.077nm, respectively. The former has the superstructure of 3.24nm, and the latter has the superstructure of 2.7nm and is incommensurate in the b direction.

Influence of vacuum degree on growth of Bi_2Te_3 single crystal

Bi2Te3single crystals were prepared by the solid-state reaction method. The effect of the vacuum on the growth of Bi2Te3 single crystals was studied with varying the oxygen content by controlling the air pressure in the silica tube. High quality Bi2Te3 single crystals have been obtained and there is no influence on the growth by an extremely small amount of oxygen in a high vacuum at 1.0 × 10^-3Pa. As the air pressure is increased at 1.0 × 10^-2Pa, oxygen only mainly impacts on the growth of the surface for the prepared samples. Micron-sized rod-like structure and flower-like clusters are observed on the surface. For the samples prepared at 1.0 × 10^-1Pa, x-ray diffraction data show that the yellow part on the surface is Bi2TeO5, while the Bi2Te3 single crystal is still the major phase as the inside part. More interestingly, various crystal morphologies are observed by scanning electron microscope for Bi2Te3 near the boundary between Bi2Te3 and Bi2TeO5.Possible growth mechanisms for Bi2Te3 with different morphologies are discussed in detail.

Efficient 2.7-μm emission in Er^(3+)-doped bismuth germanate glass pumped by 980-nm laser diode

An Er3＋-doped lead-free bismuth germanate glass is synthesized. Its 2.7-μm emission property is analyzed, and the efficient 2.7-μm emission from the glass is observed under 980-nm laser diode excitation. The prepared glass possesses high spontaneous transition probability （64.8 s^-1） and a large calculated emission cross section （6.61× 10^-21 cm^2） corresponding to the ^4Ⅰ11/2 →4Ⅰ13/2 transition. The multiphonon relaxation rate for the excited state 4Ⅰ11/2 is only 236 s^-1. Therefore, the excellent spectroscopic properties and outstanding thermal stability suggest that this glass is a suitable host for developing solid-state lasers operating in the mid-infrared.

Write-once medium with BiO_x thin films for blue laser recording

BiOx films are prepared by reactive direct current （DC） magnetron sputtering from a metallic bismuth target in Ar ＋O2 with different O2/Ar ratios. It is found that the optical property of BiOx films is sensitive to O2/Ar ratios and the films deposited at O2/Ar ratio of 0.5 have the best reflectivity contrast under the same conditions. The structure and optical characteristics of the films are studied by X-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS）, and spectrophotometer. As revealed by investigations, the phase transition is mainly responsible for the change of optical properties. The static test results indicate that the BiO~ films have good writing sensitivity for blue laser beams. A high reflectivity contrast of about 52% at a writing power of 11 mW and writing pulse width of 800 ns is obtained. In addition, the films demonstrate good stability after being read for 10000 times.

Predicted a honeycomb metallic BiC and a direct semiconducting Bi_(2)C monolayer as excellent CO_(2)adsorbents

We predicted two stable two-dimensional materials of carbon and bismuth elements,namely BiC and Bi_(2)C monolayers.The stabilities of two monolayers were examined by cohesive energy,Born criteria,first-principle MD simulations and phonon spectra,respectively.By including the spin-orbit coupling effects,the BiC monolayer is a metal and the Bi_(2)C monolayer possesses a narrow direct(indirect)band gap of 0.403(0.126)eV under the HSE06(GGA-PBE)functional.For the adsorption of CO_(2)molecules,the BiC and Bi_(2)C monolayers have three stable adsorption sites C2,T3 and T4 with the adsorption energies as-0.57,-0.51 and-0.81 eV,and the activation ability on the adsorption as T4>T3>C2.These consequences make the BiC and Bi_(2)C monolayers to be promising adsorbents to capture CO_(2)gas,the Bi_(2)C monolayer to be well photovoltaics and optoelectronics material,and the BiC monolayer to be ideal battery and electronics materials,respectively.