Bromine doped g-C3N4 with enhanced photocatalytic reduction in U(VI)

Research on Chemical Intermediates - In the process of uranium mining and smelting, large quantities of low-concentration uranium-containing wastewater have been produced. It is an ideal solution...     

Visible light induced tandem reactions: An efficient one pot strategy for constructing quinazolinones using in-situ formed aldehydes under photocatalyst-free and room-temperature conditions

A facile tandem route has been developed for constructing quinazolinones from various aminobenzamides and in-situ generated aldehydes. Visible light was found to play a dual role: first oxidizes the alcohol to the aldehyde and then facilitates its cyclization with o-substituted aniline. Furthermore, alcohols are perfect alternatives to aldehydes because they are greener, more available, more economical, more stable, and less toxic than aldehydes. The first reaction step continuously provides material for the second step, which effectively reduces loss through volatilization, oxidation, and polymerization of the aldehyde, while avoiding its toxicity. A variety of quinazolinones can be prepared in the presence of visible light without any additional photocatalyst. The developed synthesis protocol proceeds with the merits of mild conditions, broad substrate scope, operational simplicity, and high atom efficiency, with an eco-energy source under metal-free, photocatalyst-free, and ambient conditions.     

One-pot rapid synthesis of 4H-1-benzopyran derivatives in a deep eutectic solvent

A method for introducing a biologically active heterocycle, 2-methylquinoline into the 4-position of a 2-amino-4H-1-benzopyran skeleton is described. Choline chloride/glucose (1:1 molar ratio) was used as both the solvent and catalyst in the reaction of a salicylaldehyde, methylquinoline, and cyanoacetate to obtain 2-amino-4H-1-benzopyran derivatives in 48%–80% yields after short reaction times. The effects of the deep eutectic solvent type, substrate molar ratio, cosolvent, temperature, and reaction time were examined. The method has the advantages of simple steps, environmental friendliness, mild conditions, and wide substrate applicability. This is the first attempt to synthesize methylquinoline derivatives of 4H-1-benzopyran.     

Phosphorylation of graphehe oxide to improve adsorption of U(VI) from aquaeous solutions

Journal of Radioanalytical and Nuclear Chemistry - The graphene oxide (GO) was functionalized with phosphate groups and applied as an effective adsorbent for the removal of uranium from aqueous...     

离子液体与微波协同促进有机合成反应

介绍了离子液体作溶剂、助溶剂、催化剂和反应试剂与微波协同促进有机合成的研究进展。离子液体与微波协同促进有机合成反应,缩短了反应时间,提高了反应的选择性和产率,对环境更加友好。     

深共融溶剂中合成2,4-二取代喹啉衍生物

在氯化胆碱和氯化锌组成的深共融溶剂中,以2-氨基苯乙酮和芳香炔烃为原料,通过环化偶联反应,合成了一系列2,4-二取代喹啉衍生物;当n(氯化胆碱)∶n(氯化锌)=1∶2,反应温度为80℃时,反应3 h即获得高达98%的产率.该方法无需额外添加催化剂,而且反应条件温和、操作简单、底物范围较广泛.     

Electrosynthesis of highly conducting poly(1,5-dihydroxynaphthalene) in BF3·Et2O

Direct anodic oxidation of 1,5-dihydroxynaphthalene (DHN), an important derivative of naphthalene, led to the formation of high-quality semiconducting poly(1,5-dihydroxynaphthalene) (PDHN) on stainless steel sheets in boron trifluoride diethyl etherate (BFEE). The onset oxidation potential of DHN in this medium was measured to be only 0.78 V vs. SCE, which was lower than that determined in traditional acetonitrile containing 0.1 mol/L tetrabutylammonium tetrafluoroborate (0.98 V vs. SCE). As-formed PDHN films showed good redox activity and stability, together with interesting electrochromic property from brown (doped) to yellow-green (dedoped). Structural characterization, including FTIR, ¹H NMR, and quantum chemistry calculations, indicated that the polymerization of DHN probably occurred at C₄ and C₈ positions. Moreover, thermal analysis revealed that PDHN displayed better thermal stability than that synthesized by chemical method. The fluorescence spectral studies, together with the electrical tests, showed that PDHN was a good blue light-emitter (fluorescence quantum yield higher than 0.1) with an electrical conductivity of as high as 0.46 S/cm.     

Electrosyntheses and characterization of polyalkylenedioxybenzenes

Direct anodic oxidation of 1,2-methylenedioxybenzene (MDOB) and 1,2-ethylenedioxybenzene (EDOB), analogues of 3,4-alkylenedioxythiophene and 3,4-alkylenedioxypyrrole, led to the formation of polyacetylene derivatives, poly(1,2-methylenedioxybenzene) (PMDOB) and poly(1,2-ethylenedioxybenzene) (PEDOB), on a platinum sheet in pure boron trifluoride diethyl etherate (BFEE). IR, ¹H NMR, ¹³C NMR and quantum chemistry calculations confirmed that the polymerization occurred at C(4) and C(5) position on the benzene ring of the monomer, making the main backbone of PMDOB and PEDOB similar to polyacetylene. Both dedoped PMDOB and PEDOB in DMSO solution showed good fluorescence properties with quantum yields of 0.13 and 0.27, emitting blue and green light under excitation of 365 nm, respectively. PMDOB showed electrochromic properties from grass green (doped) to light nacarat (dedoped). PEDOB changed it from bottle green (doped) to nacarat (dedoped). Doped PMDOB and PEDOB own electrical conductivities of 0.1 S cm⁻¹ and 0.17 S cm⁻¹, respectively.     

用PM3量化参数预测多氯代二苯并呋喃的logKow

从现有的PCDFs分子的正辛醇 /水分配系数 (logKow)实验数据出发 ,建立定量结构 性质关系方程(QSPR) .采用G98W程序包中的PM3方法对 13 5个多氯代二苯并呋喃 (PCDFs)分子和二苯并呋喃进行了优化计算 ,作业命令为 #pPM3optfreqscf(conver =9) ,以计算所得的分子轨道能量、碳原子电荷作为PCDFs分子结构描述符 ,运用多元线性回归技术建立了PCDFs的logKow与分子结构描述符的四元方程 ,最优相关系数为 0 .95 0 7,标准偏差为 0 .173 7,经检验该模型的稳健性好 ,并对未有实验数据的 85个PCDFs的logKow进行预测     

Substituent effects on the properties of photochromic diarylethenes

Photochromic symmetrical diarylethenes 1o-5o bearing different electron-donating or electron-withdrawing substitutents have been synthesized, and the structures of 1o, 2o, 4o, and 5o were determined by single-crystal X-ray diffraction analysis. Substitutent effects on their optoelectronic properties, including photochromism, fluorescence, and electrochemical properties were investigated in detail. The electron-withdrawing substituents can shift significantly the absorption maxima of the diarylethenes to a longer wavelength and increase their cyclization quantum yield, while the molar absorption coefficients increased with an increasing electron-donating ability. Diarylethenes 1, 2, and 4 show good photochromism both in solution and in the single crystalline phase; however, diarylethenes 5 show no photochromism in the crystalline phase because the distance between the reactive carbons become larger than 4.2 Å. Diarylethenes 1-3 exhibited good fluorescent switching upon alternating irradiation with UV and visible light, and their fluorescent conversions in the photostationary state were all larger than 80% in hexane. In addition, cyclic voltammetry tests showed that different electron-donating and electron-withdrawing substituents had a remarkable effect on the electrochemical behaviors of these diarylethenes.