Two‐Dimensional Conjugated Aromatic Networks as High‐Site‐Density and Single‐Atom Electrocatalysts for the Oxygen Reduction Reaction

Two‐dimensional conjugated aromatic networks (CAN) with ultra‐thin conjugated layers (ca. 3.5 nm) and high single‐metal‐atom‐site density (mass content of 10.7 wt %, and 0.73 metal atoms per nm²) are prepared via a facile pyrolysis‐free route involving a one‐step ball milling of the solid‐phase‐synthesized polyphthalocyanine. These materials display outstanding oxygen reduction reaction (ORR) mass activity of 47 mA mg_cat.^?1 represents 1.3‐ and 6.4‐fold enhancements compared to Pt and Pt/C in benchmark Pt/C, respectively. Moreover, the primary Zn‐air batteries constructed with CAN as an air electrode demonstrate a mass/volume power density of 880 W g_cat.^?1/615 W cm_cat.^?3 and stable long‐term operation for 100 h. This strategy offers a new way to design high‐performance electrocatalysts with atomic precision for use in other energy‐storage and conversion applications.     

NH4I/1,10-phenanthroline catalyzed direct sulfenylation of N-heteroarenes with ethyl arylsulfinates

An efficient synthesis of N-heterocyclic aryl sulfides via NH₄I/1,10-phenanthroline-catalyzed direct sulfenylation reactions was reported. In this reaction, heteroarenes such as indoles, and pyrroles serve as nucleophiles by installing a arylthio group at the C3 and C2 position of heterocycles, respectively. With readily accessible and free of unpleasant odor ethyl arylsulfinates as sulfur reagents, the metal-free-catalyzed direct sulfenylation of N-heteroarenes has been developed. 3-Arylthio-indoles and 2-arylthio-pyrroles derivatives were obtained in moderate to excellent yields, even on gram scale. The reaction was general for a broad scope of substrates and demonstrated good tolerance to a variety of functional groups.     

Phosphorylated mesoporous carbon as a solid acid catalyst

Mesoporous carbon catalyst supports are attractive due to their wide chemical stability while potentially increasing mass-transport through and providing a path for larger molecules to access catalytic sites. Herein we report the synthesis of a phosphorylated mesoporous carbon solid-acid catalyst characterized by NH(3)-TPD and isopropanol dehydration.     

Ultraviolet-C light for treatment of Candida albicans burn infection in mice

Burn patients are at high risk of invasive fungal infections, which are a leading cause of morbidity, mortality, and related expense exacerbated by the emergence of drug resistant fungal strains. In this study, we investigated the use of UVC light (254 nm) for the treatment of yeast Candida albicans infection in mouse third degree burns. In vitro studies demonstrated that UVC could selectively kill the pathogenic C. albicans compared with a normal mouse keratinocyte cell line in a light exposure dependent manner. A mouse model of chronic C. albicans infection in non-lethal third degree burns was developed. The C. albicans strain was stably transformed with a version of the Gaussia princeps luciferase gene that allowed real-time bioluminescence imaging of the progression of C. albicans infection. UVC treatment with a single exposure carried out on day 0 (30 min postinfection) gave an average 2.16-log(10)-unit (99.2%) loss of fungal luminescence when 2.92 J cm(-2) UVC had been delivered, while UVC 24 h postinfection gave 1.94-log(10)-unit (95.8%) reduction of fungal luminescence after 6.48 J cm(-2). Statistical analysis demonstrated that UVC treatment carried out on both day 0 and day 1 significantly reduced the fungal bioburden of infected burns. UVC was found to be superior to a topical antifungal drug, nystatin cream. UVC was tested on normal mouse skin and no gross damage was observed 24 h after 6.48 J cm(-2). DNA lesions (cyclobutane pyrimidine dimers) were observed by immunofluorescence in normal mouse skin immediately after a 6.48 J cm(-2) UVC exposure, but the lesions were extensively repaired at 24 h after UVC exposure.     

Density functional theory study of the structure and energetics of negatively charged oligopyrroles

First‐principles calculations are used to investigate the electronic properties of negatively charged n‐pyrrole oligomers with n = 2–18. Chains of neutral oligomers are bent, whereas the negatively charged oligomers become almost planar due to accumulation of negative charge at the end monomers. Isomers of short oligomers (n < 6) display negative electron affinity although the corresponding anions are energetically stable. For longer oligomers with n ≥ 6, the electron affinity is small and positive, slowly increasing with oligopyrrole length. Doping of 12‐pyrrole with lithium atoms shows that negative oxidation states are possible due to electron transfer from dopant to oligomer at locations close to dopant. These 12‐pyrrole regions support extra negative charge and exhibit a local structural change from benzenoid to quinoid structure in the C? C backbone conjugation. Comparison between neutral and doped polypyrrole (PPy) indicates that doped polymers displays a substantial depletion of the band gap energy and the appearance of dopant‐based bands in the gap for a 50% per monomer doping level. It is predicted that Li‐doped PPy is not metallic. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011     

痕量银的催化动力学光度法研究——银(Ⅰ)-乙二胺-过硫酸铵-还原型酚酞新体系

催化动力学法测定银的指示反应多为配他体取代反应与氧化还原反应,通常以后者的灵敏度较高,重现性较好,Mueller依据过硫酸钾-对氨基苯磺酸-乙二胺反应体系建立的催化动力学法,其灵敏度达1×10^-3μg/ml。     

Kinetics of the Reaction of Abstracting Hydrogen from Ethylene by Hydrogen Atom

Hydrogen abstraction reaction, H C2H4 --H2 C2H2 was studied by using A initio SCF method. Ge-ometries were fully optimized at SCF level and energies were computed at STO-3G basis set for reactants and transition state. Vibrational analysis was performed thereupon. Finally, the rate constant calculations were carried out at different temperatures for all range of reaction temperature according to Eyring's sbwlute reaction rate theory. The calculated activation energy is 12. 68 kcal/mol, lower than observed value (H. S kcal/mol) by 1. 82 kcal/mol only. The agreement of the calculated rate constants with the experiments is satisfactory.     

Metal and acid-free visible light-mediated Friedel-Crafts alkylation reactions of indole with anilines

Metal and acid-free visible light-induced Friedel-Crafts C3-alkylation reactions of indole derivatives were developed using N,N-dimethylanilines as the carbon source. A cheap and readily available organic dye, Rose Bengal, was applied as the photocatalyst. This environmentally friendly transformation afforded C3-alkylated indoles in moderate to good yields under mild conditions.     

一种高效、绿色制备环状硫碘盐的新方法及其在染料敏化太阳电池中的应用

采用高压釜合成和乙酸乙酯/水萃取提纯的模式制备出高产率、高纯度的环状烷基硫碘盐. 高压釜合成在保证产率的前提下, 大大缩短了反应时间(反应时间仅为原来的1/3)|乙酸乙酯和水的萃取提纯模式在保证产品纯度的同时, 大大缩短了提纯时间, 还避免了有毒试剂的使用. 制备出的烷基环状硫碘盐作为碘源用于配制染料敏化太阳电池用电解质, 相应电池的光电转化效率接近使用传统烷基咪唑碘盐的电池. 电化学阻抗谱(EIS)测试表明环状烷基锍阳离子相比于烷基咪唑阳离子来说, 更有利于抑制电池内部的电子复合反应, 同时还能促进对电极上电子交换反应的进行, 最终可以提高电池的开路电压和填充因子.