氮杂环卡宾羰基氯钌配合物的合成、晶体结构及催化性质(英文)

合成了2个N-杂环卡宾钌配合物[RuCl2(L1)(CO)](1),L1=(2,6-二(甲基咪唑-2-鎓盐)吡啶)和[RuCl2(L2)(CO)](2),L2=(2,6-二(正丁基-2-鎓盐)吡啶),并通过元素分析、红外光谱、核磁共振氢谱和核磁共振碳谱对它们的结构进行了表征,X-射线单晶衍射测定了配合物2的分子结构,结果表明配合物2属单斜晶系,C2/c空间群,a=1.814 8(4)nm,b=1.129 2(3)nm,c=1.119 6(2)nm,β=108.862(3)°,且中心Ru(Ⅱ)离子是六配位,同时研究了配合物1和2在Suzuki-Miyaura偶联反应中的催化性质。     

Unified Model for Generation Complex Networks with Utility Preferential Attachment

In this paper, based on the utility preferential attachment, we propose a new unified model to generate different network topologies such as scale-free, small-world and random networks. Moreover, a new network structure named super scale network is found, which has monopoly characteristic in our simulation experiments. Finally, the characteristics of this new network are given.     

Copper-catalyzed solvent-free redox condensation of benzothiazoles with aldehydes or benzylic alcohols

An efficient and practical method for the construction of 2-aryl- and 2-alkyl-substituted benzothiazoles via a copper-catalyzed redox condensation process between benzothiazoles and aldehydes or benzylic alcohols has been developed. The reaction proceeded under mild reaction conditions using environmentally benign tert-butyl hydroperoxide (TBHP) as the oxidant. A reaction mechanism involving the ring-opening of benzothiazoles initiated by the attack of acyl radical on the thiazole ring and intramolecular condensation is proposed based on the isolation of an anilide disulfide intermediate.     

用水发电的那些事*

水不仅是生命之源,而且还作为介质为人类提供了极其丰富的绿色能源。选取了几种利用水驱动发电的技术,包括传统水力发电、潮汐能发电、海洋温差发电,也详细探讨了近年新兴的盐差发电和“水伏”发电,力求以通俗的语言将水发电技术进行科普介绍。     

Microwave-Assisted Hydrothermal Preparation, Characterization and Photocatalytic Properties of a Chrysanthemum-Shaped ZnWO4 Photocatalyst

A novel chrysanthemum-shaped monocline ZnWO₄ photocatalyst was synthesized by microwave-assisted hydrothermal method with Na₂WO₄·2H₂O and Zn(NO₃)₂·6H₂O as raw materials at different reaction temperatures. The prepared ZnWO₄ photocatalysts were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, Field emission scanning electron microscopy (FE-SEM), Transmission electron microscopy, Photoluminescence spectrum (PL) and UV–Vis absorption spectrum (UV–Vis). The photocatalytic property of the prepared chrysanthemum-shaped monocline ZnWO₄ photocatalyst was evaluated by the degradation of Rhodamine B (RhB) in aqueous solution. The effects of reaction temperature on the photocatalytic degradation efficiency of RhB were investigated. The results indicated that the chrysanthemum-shaped monocline ZnWO₄ photocatalyst is prepared by foliated powders with the sizes of about 30 nm and 500 nm respectively at 160 and 220 °C. The PL relative intensity of prepared ZnWO₄ photocatalyst is apparently intensifying with increasing temperature. The photocatalytic property decreases with the increasing recombination probability of the excited electrons and holes. The chrysanthemum-shaped monocline ZnWO₄ photocatalyst prepared at 160 °C possesses the best photocatalytic property, and the degradation efficiency of RhB at 180 min UV-light irradiation is achieved 75 %. The ZnWO₄ has good reusability property on degradation of RhB and the degradation rate is still higher than 65 % after three cycles.     

激光剥蚀电感耦合等离子体质谱法测定碳化硅器件中杂质元素

采用激光剥蚀电感耦合等离子体质谱法(LA-ICP-MS),以NIST玻璃标准物质制作校准曲线,29Si为内标,相对灵敏度因子(RSF)校准标样和样品间的基体效应,对碳化硅陶瓷器件中9种痕量元素(B,Ti,Cr,Mn,Fe和Ni等)进行定量测定。选择线性扫描方式,激光剥蚀孔径为150μm,氦气和氩气流量为0.7 L/min时,信号稳定性和灵敏度最佳。经内标校准后,各元素标准曲线的线性有较大改善,线性相关系数为0.9981~0.9999。以建立的方法对碳化硅标准参考物质(BAM-S003)中的痕量元素进行测定,并与标准参考值进行对比,结果一致,证实了LA-ICP-MS方法应用于碳化硅样品检测的准确性和有效性。采用本方法定量测定碳化硅器件中痕量元素,结果与辉光放电质谱法(GD-MS)测定的结果比较一致。元素B,Ti,Cr,Mn,Fe,Ni,Cu,Sr和La的检出限为0.004~0.08 mg/kg,相对标准偏差(RSD)小于5%。     

A squaraine based fluorescent probe for mercury ion via coordination induced deaggregation signaling

Due to the high affinity between dithiocarbamate(DTC) and Hg2+,a fluorescent probe based on squaraine chromophore with DTC side arm for Hg2+via coordination induced deaggregation signaling has been designed and synthesized.Squaraine has a high tendency to aggregate in aqueous solution,and such self-aggregation usually results in a dramatic absorption spectral broadening with fluorescence emission quenching.The combination of the DTC side arm of the probe with Hg2+induces steric hindrance,leading to the deaggregation of the dye complex,companying with a fluorescence emission restoration.In EtOH–H2O(20:80,v/v) solution,this ‘‘turn on' fluorescent probe has high selectivity and sensitivity toward Hg2+over other metal ions,and the limit of detection for Hg2+was estimated as2.19 ? 10à8mol/L by 3s/k.     

Mo离子注入对金刚石涂层附着性能的影响

采用Mo离子注入工艺对YG6硬质合金基体表面进行处理,用微波等离子体CVD(MPCVD)法沉积金刚石涂层,研究了Mo离子注入工艺对金刚石涂层附着性能的影响.结果表明,Mo离子注入后,硬质合金基体表面的化学成分发生了明显变化;采用适当剂量的Mo离子注入基体,可使CVD金刚石涂层的附着性能显著提高. 关键词： 金刚石涂层 Mo离子注入 硬质合金基体 附着性能     

Interaction of bioactive components caffeoylquinic Acid derivatives in Chinese medicines with bovine serum albumin

Five caffeoylquinic acid derivatives (CQAs), including methyl 3,4-di-O-caffeoylquinate (3,4-diCQM), methyl 3,5-di-O-caffeoylquinate (3,5-diCQM), 3,4-di-O-caffeoylquinic acid (3,4-diCQA), 3,5-di-O-caffeoylquinic acid (3,5-diCQA) and chlorogenic acid (CA), were isolated from Lonicera fulvotomentosa HSU et S. C. CHENG to be used as model compounds. The binding of these bioactive components to bovine serum albumin (BSA) was investigated by fluorescence quenching method. The results showed that there were binding affinities for CQAs with BSA, and the binding constants ranked in the following order: 3,4-diCQM>3,5-diCQM<3,4-diCQA>3,5-diCQA>CA, under the physiological conditions, which suggested that the numbers and the substituted positions of caffeoyl group as well as the esterification of carboxyl group in the molecular structures appeared to contribute moderate effects to the interaction processes. Furthermore, the Stern-Volmer curves demonstrated that CQAs caused the fluorescence quenching through a static quenching procedure. Thermodynamic analysis indicated that both hydrophobic and electrostatic interactions played major roles in stabilizing the complex. The binding distance for each binding reaction was also calculated by the F?ster theory.