新型两亲性混配钌配合物的合成及其对Hg2+的选择性“肉眼”识别

采用与文献不同的路线合成了4,4′-二(p-甲基苯基)-2,2′-二联吡啶,与文献结果相比,总收率由4.0%提高至15.3%.该化合物和4,4′-二羧基-2,2′-二联吡啶组成混合配体与金属钌配位,合成了两亲性、混配型配合物cis-N,N-4,4′-二(p-甲基)苯基-2,2′-二联吡啶-N,N-4,4′-二羧基-2,2′-二联吡啶-N,N-二异硫氰钌配合物,并用IR,UV-Vis,NMR和Maldi-TOF等手段进行表征.将该两亲性混配钌配合物首次用于对Hg2+的识别中,发现此配合物对Hg2+表现出灵敏的选择性“肉眼”识别:在DMF/乙醇溶液(体积比1∶9)中加入Hg2+后,MLCT态吸收由530nm蓝移到485nm.该配合物与Hg2+以1∶1(摩尔比)结合,检测限可低至0.5×10-6mol/L.     

α-Tetralone glycosides from the green walnut husks of Juglans mandshurica Maxim. and their cytotoxic activities

Abstract

Five new α-tetralone glycosides, juglanbiosides A-E (1–5), together with an α-tetralone derivative (15) and nine known 1,4-naphthoquinones (6–14) were isolated from the 95% EtOH extract of green walnut husks of Juglans mandshurica Maxim. Their structures were elucidated by comprehensive spectroscopic methods (¹H, ¹³C NMR, DEPT, HSQC, HMBC, CD, HR-ESI-MS). In vitro cytotoxicities of all the isolated compounds were evaluated against BGC-823, HCT-15 and K562 cancer cell lines.

     

A Self-Diffraction Temporal Filter for Contrast Enhancement in Femtosecond Ultra-High Intensity Laser

We demonstrated a nonlinear temporal filter based on the self-diffraction(SD) process. Temporal contrast enhancement, angular dispersion and spectrum broadening properties of the SD process are investigated in experiment and simulation. Driven by spectral phase well compensated laser pulses with bandwidth of 28 nm,the filter produced clean pulses with a temporal contrast higher than 1010 and excellent spatial profile, the spectrum of which was smoothed and broadened to 64 nm. After implementing this filter into a home-made30 TW Ti:sapphire amplifier, temporal contrast of the amplified pulses was enhanced to 1010 within the time scale of-400 ps.     

纳米CoSe修饰氮掺杂多孔碳的可控制备及其锂硫电池多硫化物的催化转化效应

锂硫电池中较差的循环稳定性和倍率性能是实现锂硫电池商业化的技术障碍,其主要原因之一是多硫化物在硫电极内的电化学转化速率较为缓慢。为此,我们以ZIF-9为前驱体,采用先碳化,再酸化刻蚀,最后硒化的方法合成了含少量催化剂的CoSe修饰氮掺杂多孔碳(CoSe/NC)电极材料,以期提高硫电极内多硫化物的电化学转化动力学性能,并通过流动液相三电极体系对该材料进行电化学动力学表征。结果显示,相较于对比材料,CoSe/NC能够加快多硫化物的氧化还原反应速率,在0.2mA·cm-2电流密度下,多硫化物氧化还原反应在CoSe/NC电极上有最小的反应过电位;同时,在0.1 V过电位下,各氧化还原反应也有最大的响应电流。因此,将CoSe/NC作为硫宿主材料组装电池展现了优异的电化学性能：在1C(1C=1 675 mA·g^-1)下初始放电比容量为1 068 mAh·g^-1,经过500次循环后,可逆容量仍保持在693 mAh·g^-1。另外,在3C的高电流密度下,放电比容量可高达819 mAh·g-1。     

三种基于2,4,6-三(3-吡啶基)-1,3,5-苯配体的Ni(Ⅱ)基配位聚合物的合成、结构及催化性能

通过调变溶剂热的反应条件,我们合成了3种Ni(Ⅱ)基的配位聚合物(CPs)[Ni (CH₃-BDC)(3-TBT)(H₂O)₂]·EtOH·2H₂O (CP1)、[Ni₃(CH₃-BDC)₃(3-TBT)₂(H₂O)₅]·2DMF·2H₂O (CP2)和[Ni₃(CH₃-BDC)₃(3-TBT)₂(H₂O)₆]·2DMF·4H2O (CP3),其中CH₃-H₂BDC=5-methyl isophthalic acid,3-TBT=2,4,6-tris (3-pyridyl)-1,3,5-benzene。X射线单晶衍射分析表明,3个CPs都是由相似的Ni₂(CH₃-BDC)₂的双核单元构建的,并分别呈现出从零维(0D)、2D到3D结构的网络骨架。反应条件的微小调变,导致了不同结构的配位聚合物。同时,催化实验表明,3在无溶剂的温和反应条件下,CP3对苄醇及其衍生物与苯胺的氧化-偶联反应表现出极好的催化活性和循环稳定性。     

BiOI负载MIL-101(Fe)@BiOI衍生BiFeO3@Fe2O3及其增强光催化性能

采用溶剂热法合成了MIL-101(Fe)@BiOI复合材料,然后将其煅烧制备光催化性能增强的BiFeO₃@Fe₂O₃@BiOI三元复合材料。采用X射线衍射、扫描电镜、紫外可见漫反射吸收光谱等测试手段表征复合材料的组成、结构、形貌。将复合材料用于可见光照射下光催化降解四环素,研究复合比例(质量比)、pH和浓度对光催化性能的影响。电化学阻抗谱、光电流响应和莫特-肖特基曲线测试分析表明三元复合材料BiFeO₃@Fe₂O₃@BiOI表现出更强的光电流响应和更低的电荷转移电阻。当BiFeO₃、Fe₂O₃和BiOI三者理论质量比为1∶1∶1时,中性条件下降解活性最高,四环素去除率为81%。     

Synthesis of Diversified Pyrazolo[3,4-b]pyridine Frameworks from 5-Aminopyrazoles and Alkynyl Aldehydes via Switchable C≡C Bond Activation Approaches

A cascade 6-endo-dig cyclization reaction was developed for the switchable synthesis of halogen and non-halogen-functionalized pyrazolo[3,4-b]pyridines from 5-aminopyrazoles and alkynyl aldehydes via C≡C bond activation with silver, iodine, or NBS. In addition to its wide substrate scope, the reaction showed good functional group tolerance as well as excellent regional selectivity. This new protocol manipulated three natural products, and the arylation, alkynylation, alkenylation, and selenization of iodine-functionalized products. These reactions demonstrated the potential applications of this new method.     

反相微乳液法制备纳米Ag2S增感剂的化学增感研究

本文用反相微乳液法制备了纳米Ag₂S,并用作卤化银乳剂的硫增感剂,研究了其增感效果、增感规律及可能的增感机理.反相微乳液由异辛烷、表面活性剂AOT钠盐和水形成;制得的Ag₂S粒径3—5 nm;用制得颗粒增感卤化银乳剂,获得的感光性能优越于用Na₂S₂O₃水溶液增感;增感规律的研究表明,随着乳剂中纳米Ag₂S浓度的增加,模型乳剂感光度迅速提高、灰雾变化不大,并在100—200μmol/molAg左右获得最佳感光性能,进一步增加浓度则感光度呈下降趋势、灰雾升高;获得最佳感光性能所需的化学增感时间很短,约40分钟,之后感光度不再增加、灰雾上升;用漫反射光谱(DRS)作探针,跟踪记录增感时卤化银微晶表面上纳米Ag₂S增感剂颗粒的演变,为新型纳米增感剂的优异增感特性提供了机理性解释.     

多片导模法蓝宝石晶体的缺陷研究

使用导模法(EFG)生长了多片a面蓝宝石晶体。显微拉曼光谱结合电感耦合等离子体发射光谱(ICP-AES)测试得出晶体的气泡中可能存在含S化合物。晶体表面明显的生长条纹主要与温度、生长速度的波动以及模具的加工精度有关。化学腐蚀分析表明晶体位错密度在4.2×10⁴ cm^-2,未存在小角度晶界缺陷,双晶摇摆曲线半峰宽(FWHM)为70.63″。由于采用石墨保温材料,晶体中存在F心与F⁺色心。晶体在400~3 000 nm波段透过率高于80%,空气中退火后可减弱色心吸收。本文研究结果可为蓝宝石晶体缺陷形成理论研究提供参考,也可为导模法蓝宝石工业生产技术改进提供借鉴。