Synthesis, spectroscopic characterization, DFT studies and biological assays of a novel gold(I) complex with 2-mercaptothiazoline

A new gold(I) complex with 2-mercaptothiazoline (MTZ) with the coordination formula [AuCN(C₃H₅NS₂)] was synthesized and characterized by chemical and spectroscopic measurements, DFT studies and biological assays. Infrared (IR) and ¹H, ¹³C and ¹⁵N nuclear magnetic resonance (NMR) spectroscopic measurements indicate coordination of the ligand to gold(I) through the nitrogen atom. Studies based on DFT confirmed nitrogen coordination to gold(I) as a minimum of the potential energy surface with calculations of the hessians showing no imaginary frequencies. Thermal decomposition starts at temperatures near 160 °C, leading to the formation of Au⁰ as the final residue at 1000 °C. The gold(I) complex with 2-mercaptothiazoline (Au-MTZ) is soluble in dimethyl sulfoxide (DMSO), and is insoluble in water, methanol, ethanol, acetonitrile and hexane. The antibacterial activities of the Au-MTZ complex were evaluated by an antibiogram assay using the disc diffusion method. The compound showed an effective antibacterial activity against Staphylococcus aureus (Gram-positive) and Escherichia coli and Pseudomonas aeruginosa (Gram-negative) bacterial cells. Biological analysis for evaluation of the cytotoxic effect of the Au-MTZ complex was performed using HeLa cells derived from human cervical adenocarcinoma. The complex presented a potent cytotoxic activity, inducing 85% of cell death at a concentration of 2.0 μmol L⁻¹.     

Efficient eco-friendly approach towards bimetallic nanoparticles synthesis and characterization using Exiguobacterium aestuarii by statistical optimization

ABSTRACT

Biogenic synthesis of bimetallic nanoparticles (gold – AuNp and selenium – SeNp) using inexpensive Tryptophan Enriched Banana Peel Media for the growth of marine isolate (Exiguobacterium aestuarii SBG4 MH185868). The response surface methodology is employed for optimizing production conditions. The surface plasmon resonance band showed λ_max at 540?nm (AuNp) and 284?nm (SeNp). FTIR and zeta potential analysis confirmed the stability, whereas XRD spectra revealed the nature of nanoparticles obtained at optimum conditions. SEM micrographs showed nanospheres of the following size: AuN, 30?±?5 nm and SeNp, 50?±?5 nm. Biocompatibility of Np evaluated by the hemolytic activity showed <20% hemolysis even at highest concentrations (100?µg/ml). AuNp showed the least cytotoxicity, whereas SeNp showed considerable cytotoxicity against the breast cancer cell lines MCF – 7 and MDA-MB-231. Hence, we utilized the environment-friendly growth media for the controlled synthesis of dual Np using single bacterial strain involving feasible steps in downstream processing.     

Structural and electrochemical properties of high-capacity Ml-Mg-Ni-based hydrogen storage alloys

The Ml-Mg-Ni-based (Ml = La-rich mixed lanthanide) hydrogen storage alloy Ml_0.88Mg_0.12Ni_3.0-Mn_0.10Co_0.55Al_0.10 was prepared by inductive melting. The micro-structure was analyzed by XRD and SEM. The alloy consists mainly of CaCu₅-type phase, Ce₂Ni₇-type phase and Pr₅Co₁₉-type phase. The electrochemical measurements show that the maximum discharge capacity is 386 mAh/g, 16.3% higher than that of the commercial AB₅-type alloy (332 mAh/g). At discharge current density of 1 100 mA/g, high rate dischargeability is 62%, while that of the AB5-type alloy is only 45%. The discharge capacity decreases to 315 mAh/g after 300 charge/ discharge cycles, 81.5% of the maximum discharge capacity. __________ Translated from Journal of Xi’an Jiao Tong University, 2008, 42(3) (in Chinese)     

镍氢电池的循环性能与活性物质微结构的研究

与循环试验大致同步, 用静态(初态和终态)或准动态(增加若干个中间态)的模式对MH/H电池循环性能、电极(包括负极和正极)材料的微结构进行了X射线衍射(XRD)研究, 发现循环性能衰减与正极材料β-Ni(OH)₂的点阵参数、平均晶粒尺度、微应变和总的层错几率均随循环周期增加而减小以及负极材料中腐蚀产物A(OH)₃和B相出现和增加有一定的对应关系, 发现MH/Ni 电池循环性能的衰减是正极材料和负极材料的结构和微结构随着循环次数的增加发生明显变化, 恶化了正负极材料的电化学性能, 同时消耗和恶化了电解液的综合结果. 为了提高电池的循环性能, 采用不同正极材料的添加剂. 结果表明, CaF₂和Lu₂O₃有明显的效果, 其中CaF₂效果最好, 并有广泛的实用性.     

R245fa基于MH81方程的热物性计算模型

R245fa作为替代CFC的新型工质,在高温热泵,低温发电系统等工程领域中有着广泛的使用。为满足仿真计算的需要,提出一种基于MH81方程的R245fa物性计算模型。该模型在过热区符合良好,在过冷区修正为六参数的拟合式之后,其精度与过热区相当。将计算式与物性数据进行对比,结果表明平均相对误差小于8%,最大相对误差小于13%。     

两水平无重复因析试验散度效应的估计

本文对两水平无重复因析试验给出了散度效应的一种新的估计,称为AMH估计,改进了文献中散度效应的较好的MH估计的一个缺陷,给出并证明了AMH估计的无偏条件,证明了AMH估计比MH估计有更小的方差下界.最后通过模拟试验比较了AMH和MH估计的偏度,方差和均方误差.     

酞菁类化合物对MH/Ni电池性能的影响

针对MH/Ni电池充电过程中氧的产生和不恰当的消除方式带来的内压升高和热量聚集使电池总体性能衰减很快的问题, 提出采用降低化学催化氧还原的比例, 提高热量产生少的电催化氧还原比例的方法加以解决.金属酞菁类化合物是一种电催化氧还原剂.添加酞菁的MH/Ni电池与对比电池进行容量衰减、内压、大电流放电等特性比较, 其性能均有显著提高.     

含锡AB_5型非化学计量贮氢合金Ⅱ.电化学性能

研究了几种AB5非化学计量贮氢合金的电化学性能 ,及在低电流密度与高电流密度放电下取代元素对放电比容量、活化性能及循环寿命的影响。Sn ,Co,Mn的加入有利于提高合金的电化学贮氢容量 ,La(NiSn) 5.14 ,La(NiSnCo) 5.12 和La(NiSnMn) 5.12 具有相同的电化学贮氢容量与活化特性。尽管La(NiSn) 5.14 大电流放电性能优于La(NiSnCo) 5.12 和La(NiSnMn) 5.12 ,但其寿命短。Mn ,Co和Al可大大提高合金的使用寿命。La(NiSnCo) 5.12 被认为是一种理想的贮氢合金。     

Mm(NiCoMnAl)5贮氢合金中铝对直封型MH/Ni电池性能的影响

制作电池前在正极活性物质βＮｉ（ＯＨ）２微粒表面沉积５％Ｃｏ,抑制了γＮｉＯＯＨ的产生,并能有效地防止βＮｉ（ＯＨ）２在充放循环过程中粉化,通过对电池充放电曲线的测量、Ｘ射线分析,探明了用前处理方法可消除贮氢合金中铝对正极活性物质的影响．     

Ni/MH电池过充电过程热效应分析

论文采用二维热模型分析了圆柱型Ni/MH电池在过充电过程中的热效应.实验提供了更为精准的数据以建立精确的热模型.利用石英频率微量热仪对电池的热容量以及电池在不同电流过充电时的发热量和散热速率进行了测量,继而将散热速率曲线拟合成线性函数和三段不同的指数函数.线性阶段之后的散热过程符合数学微分表达式,这些表达式有助于理解过渡阶段和过充电阶段散热速率的变化规律.热传导方程中产热速率采用理论计算值.最后使用FEM模拟了电池在1C,3C,5C充电过程每一阶段末时刻的电池内部温度场分布,结果相对准确.