FeCl3‐Catalyzed Ring‐Closing Carbonyl–Olefin Metathesis

Exploiting catalytic carbonyl–olefin metathesis is an ongoing challenge in organic synthesis. Reported herein is an FeCl₃‐catalyzed ring‐closing carbonyl–olefin metathesis. The protocol allows access to a range of carbo‐/heterocyclic alkenes with good efficiency and excellent trans diastereoselectivity. The methodology presents one of the rare examples of catalytic ring‐closing carbonyl–olefin metathesis. This process is proposed to take place by FeCl₃‐catalyzed oxetane formation followed by retro‐ring‐opening to deliver metathesis products.     

A Mixed‐Ligand Approach for a Gigantic and Hollow Heterometallic Cage {Ni64RE96} for Gas Separation and Magnetic Cooling Applications

Nanosized aggregations of metal ions shielded by organic ligands possessing both exquisite structural aesthetics and intriguing properties are fundamentally interesting. Three isostructural gigantic transition‐metal–rare‐earth heterometallic coordination cages are reported, abbreviated as {Ni₆₄RE₉₆} (RE=Gd, Dy, and Y) and obtained by a mixed‐ligand approach, each possessing a cuboidal framework made of 160 metal ions and a nanosized spherical cavity in the center. Along with the structural novelty, these hollow cages show highly selective adsorptions for CO₂ over CH₄ or N₂ at ambient temperatures. Moreover, the gadolinium analogue exhibits large magnetocaloric effect at ultralow temperatures.     

Preparation of anti-human cardiac troponin I immunomagnetic nanoparticles and biological activity assays

Maghemite nanoparticles (MNPs) were synthesized by chemical coprecipitation and coated with meso-2,3-dimercaptosuccinic acid (HOOC-CH(SH)-CH(SH)-COOH or DMSA). The morphology and properties of the nanoparticles were characterized by TEM, XRD, Zeta Potential Analyzer and VSM. Subsequentially, the anti-human cardiac troponin I (cTnI) immunomagnetic nanoparticles (IMNPs) were prepared by grafting anti-human cTnI antibodies on the surface of DMSA-coated MNPs using the linker of EDC (1-ethyl-3-[3-dimethylaminopropyl] carbodiimide hydrochloride). The conjugation amount of the antibodies and the activity of IMNPs was evaluated by enzyme linked immunosorbent assay (ELISA) and Western blotting. The results show that the physical and chemical adsorption occurred at the same time, but the former was unstable and apt to desorb, and the maximum conjugation amount of antibody was about 96 μg on the 0.1 mg MNPs by covalent bond. The stability was also investigated, and after 300 days the antibodies on the IMNPs remained the biological activity.     

Preparation and Characterization of Heteropoly-complex K_11[La(GaW_11O_39H_2)_2]· xH_2O

Heteropoly complexes K11[Ln(CaW 11O39H2)21 · x H2O(Ln=La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy ) have been prepared and analysed. Some properties such as thermal behavior, IK and UV spectra, X-ray powder diffraction, magnetic susceptibility and X-ray photoelectron spectrum have been investigated.     

水/TX-100/正己醇/正辛烷反相微乳液的物化性质

运用微量热计（Microcalorimeter）,傅立叶变换红外（FT-IR）,对水／TX-100／正己醇／正辛烷反相微乳液体系的形成过程及水的微结构进行了研究．微量热结果表明该反相微乳液的形成过程为一放热过程,且为两步反应．第一步为TX-100单体中的聚氧乙烯醚键与水分子形成氢键的过程,然后是“包裹”在反相胶束中的聚氧乙烯醚键与H2O分子形成氢键的过程,这两步反应之间存在时间差,焓变在该反相微乳液的形成过程中起着主要作用．含水量不同时,体系分别形成结合水、束缚水和自由水,并用FT-IR对此加以证实,FT-IR测试结果表明结合水、束缚水和自由水羟基吸收峰分别位于3400±20cm-1、3550±20cm-1、3220±20cm-1,在反相微乳液中脂肪醚位于比芳基醚大的极性区域,因而先于芳基醚与水作用形成氢键．     

改变云芝多糖的化学结构提高其抑瘤活性的研究

本文将长白山野生云芝子实体提取的多糖,用选择性氧化和还原及部分水解的方法,切断其β(1-6)糖苷键,明显提高了云芝多糖的抑瘤活性。此外,未脱色的云芝多糖抑瘤活性较脱色者高。     

-电感耦合等离子体质谱法测定硅锰冶炼渣中8种金属元素

实验采用HCl-HNO₃-HF-HClO₄混合酸为消解体系对样品进行前处理,加入1.0 mL盐酸羟胺溶液(100 g/L)溶解残渣,选择合适的同位素,以¹⁰³Rh为内标测定Cr、Co、Ni、Cu、Zn和Cd,以¹⁹³Ir为内标测定Tl和Pb,建立了电感耦合等离子体质谱(ICP-MS)法测定硅锰冶炼渣中8种重金属元素的方法。实验发现,样品前处理选择HCl∶HNO₃∶HF∶HClO₄=5∶5∶5∶1,并在复溶阶段加入1.0 mL盐酸羟胺溶液(100 g/L)可以完全消解样品,实验采用KED模式和干扰系数校正法消除质谱干扰,样品中待测元素的测定结果不受基体成分的干扰。通过绘制校准曲线及测定流程空白,各元素校准曲线的相关系数均大于0.9999,方法检出限为0.006~0.19 mg/kg,方法定量限为0.018~0.57 mg/kg。对硅锰渣实际样品进行测定,各元素的相对标准偏差(RSD,n=11)在0.83%~4.1%,加标回收率为94.7%~106%;经过人员比对实验,相对偏差为-4.54%~4.24%。测定结果稳定可靠,能满足硅锰冶炼渣中8种微量金属元素含量的分析检测要求。     

纳氏试剂分光光度法测定铝灰渣浸出液中的氨氮含量

随着水土资源环境日益恶化,监测氨氮量对水土的污染程度也备受关注。为了准确测定铝灰渣浸出液中的氨氮量,实验对振荡方法、振荡时间、固液比、试液过滤方式、纳氏试剂加入量以及测定干扰因素进行了研究。确定了以翻转振荡为前处理方式,最佳振荡时间为14 h,固液比为1:10,最佳纳氏试剂加入量为1.0 mL,通过改善过滤方式,降低了空白值。由实验结果可知：在试验范围内,F^-对氨氮量的测定不产生干扰;对于浸出液中Cl^-、Al³⁺和Ca²⁺浓度高的样品,可通过移取稀释液2.00 mL,加入1.0 mL酒石酸钾钠溶液(500 g/L),即可消除其干扰。运用纳氏试剂分光光度法测定铝灰渣浸出液中的氨氮量,得到氨氮标准曲线线性相关系数为0.9998,方法检出限为0.39 mg.L^-1,RSD(n=6)<5%,回收率在94.7%～105%之间。本方法简单快速,精密度高,且具有较低的检出限,适用于大批量铝灰铝渣等固体废物浸出液中氨氮量的测定。     

Coordination Chemistry of Lanthanides at “High” pH: Synthesis and Structure of the Pentadecanuclear Complex of Europium(III) with Tyrosine

A five-coordinate chloride ion is believed to template the assembly of a pentadecanuclear lanthanide complex of europium(III ). This cluster (see picture) has been prepared by coordination of europium(III ) perchlorate with tyrosine at about pH 6. Single crystal X-ray analysis established an unprecedented structure in which 15 constituent europium(III ) ions are organized into three parallel pentagonal layers.     

Ultrafast Saturable Absorption of Core/Shell Colloidal Quantum Dots

Ultrafast saturable absorption (SA) materials that are capable of blocking the optical absorption under strong excitation have extensive applications in photonic devices. This work presents core/shell colloidal quantum dots (CQDs) which have the quantized energy levels, excellent band gap tunability, and possess significant SA performance. When the band gap is close to the pump pulse energy, the CQDs show significant resonant SA response. At the same excitation conditions, the core/shell CQDs dispersions show better SA response than graphene dispersions, and comparable to the recently reported molybdenum disulfide. The carrier dynamics of the SA of the CQDs is analyzed systematically. The research has also found that the two‐photon absorption of the CQDs show nearly cubic power law of the band gap, while the SA performance keeps almost the same in the nonresonant regime. Further, superior passive Q‐switched laser behavior is observed using the CQDs as a saturable absorber. The results directly reveal the physical processes of this basic problem and broaden the applications of CQDs in photonic devices.