纳米结构Au/Fe_2O_3的制备、表征及催化氧化性能

分别以纳米和块状氧化铁为载体,通过沉积沉淀法制备了Au/Nano-Fe2O3和Au/Bulk-Fe2O3,并对其进行了表征和催化氧化性能测试。结果表明:对于Au/Nano-Fe2O3,5 nm Au颗粒被尺寸相当的Nano-Fe2O3所包覆,形成新颖的类似核壳结构;对于Au/Bulk-Fe2O3,3 nm Au颗粒高度分散于Bulk-Fe2O3的表面。在1-苯乙醇的氧化反应中,Au/Nano-Fe2O3显示出比Au/Bulk-Fe2O3更好的催化活性。活性的增强主要与小尺寸的Nano-Fe2O3以及Au和Nano-Fe2O3更大的接触界面有关。相比于广泛受到重视的Au的尺寸效应来说,对于Au/Nano-Fe2O3而言,Fe2O3尺寸的影响更大。     

Helical Poly(α,β‐unsaturated ketone) with Bulky Pendant of Binaphthyl from Anionic Polymerization of ((−)‐Menthyl (S)‐6′‐Acrylyl‐2′‐methyloxy‐1,1′‐binaphthalene‐2‐carboxylate

((?)‐Menthyl (S)‐6′‐acrylyl‐2′‐methyloxy‐1,1′‐binaphthalene‐2‐carboxylate ( 3 ) was synthesized and anionically polymerized using n‐BuLi as an initiator in toluene. The monomer 3 was levorotatory and had an [α]_D²⁵ value of ?72.4, but its corresponding polymer poly‐ 3 was dextrorotatory and showed an [α]_D²⁵ value of +162.0. Poly‐ 3 was confirmed to exist in the form of one‐handed helical structure in solution by means of comparing the specific optical rotation and the CD spectra with that of 3 and the model compounds such as (?)‐menthyl (S)‐6′‐propionyl‐2′‐methyloxy‐1,1′‐binaphthalene‐2‐carboxylate 2b and (?)‐menthyl (S)‐6′‐heptanoyl‐2′‐methyloxy‐1,1′‐binaphthalene‐2‐carboxylate 2c . This conclusion was also confirmed by the fact that the g‐value of poly‐ 3 is about 11 times of that of monomer 3 .     

Sensitive detection of DNA methyltransferase activity based on rolling circle amplification technology

This work develops a fluorescence approach for sensitive detection of DNA methyltransferase activity based on endonuclease and rolling circle amplification （RCA） technique. In the presence of DNA adenine methylation （Dam） MTase, the methylation-responsive sequence of hairpin probe is methylated and cleaved by the methylation-sensitive restriction endonuclease Dpn 1. The products cleaved by restriction endonuclease Dpn I then function as a signal primer to initiate RCA reaction by hybridizing with the circular DNA template. Each RCA product containing thousands of repeated sequences might hybridize with a large number of molecular beacons （detection probes）, resulting in an enhanced fluorescence signal. In the absence of Dam MTase, neither methylation/cleavage nor RCA reaction can be initiated and no fluorescence signal is observed. The proposed method exhibits a dynamic range from 0.5 U/mL to 30 U/mL and a detection limit of 0.18 U/mL. This method can be used for the screening of antimicrobial drugs and has a great potential to be further applied in early clinical diagnosis.     

Adsorption separation performance of H2/CH4 on ETS-4 by concentration pulse chromatography

To exploit an effective adsorbent to separate hydrogen and methane, microporous titanium silicate molecular sieve NaETS-4 was synthesized and modified by strontium. The adsorption characteristics and diffusion behaviors of the prepared titanosilicate molecular sieve were studied by concentration pulse chromatography. And the effects of ion-exchange and dehydration temperature on adsorbent structure and gas diffusion were also discussed. The results showed that the thermal stability and Henry＇s Law constants were enhanced and micropore diffusivity decreased after exchanging Na＋ with Sr2＋. With the increase of dehydration temperature, Henry＇s Law constant and micropore diffusivity of CI-I4 decreased in both NaETS-4 and SrETS-4. While for 1-12 in SrETS-4, the increase of Henry＇s Law constant and the decrease of diffusion rate can be attributed to the shrinks of pore diameter resulting from the relocation of Sr2＋. Correspondingly, the kinetic selectivity of H2/CH4 reached 8.91 indicating its potentiality in separating H2 and CH4.     

Efficient oxidation of ethylbenzene catalyzed by cobalt zeolitic imidazolate framework ZIF-67 and NHPI

Efficient catalytic oxidation of ethylbenzene to acetophenone was realized using the catalytic system of cobalt zeolitic imidazolate framework ZIF-67/N-hydroxyphthalimide （NHPI） under mild conditions. 95.2% conversion of ethylbenzene with 90.3% selectivity to acetophenone could be obtained at 373 K under 0.3 MPa 02 for 9 h. The results show that there exists synergetic effect between ZIF-67 and NHPI. 1-Phenylethyl hydroperoxide （PEHP） was generated via a radical process involving the hydrogen abstraction from ethylbenzene by phthalimide N-oxyl, and subsequently effectively decomposed to acetophenone by ZIF-67.     

超高效液相色谱-串联质谱快速检测精米、玉米与土豆样品中噻呋酰胺残留

采用分散固相萃取(QuEChERS)为样品前处理方法,建立了超高效液相色谱-串联质谱(UPLCMS/MS)快速检测精米、玉米和土豆中噻呋酰胺残留的分析方法。样品经乙腈提取,PSA净化,超高效液相色谱分离,电喷雾电离、负离子扫描,三重四极杆串联质谱以多反应监测扫描方式进行检测,基质匹配标准品外标法进行定量分析。结果显示,噻呋酰胺在1.0~1 000μg·L-1范围内呈良好线性(r2=0.999 0)。在0.01~1.0 mg·kg-1加标水平范围内,噻呋酰胺在精米、玉米和土豆中的平均回收率为89.1%~109.3%,相对标准偏差为3.5%~8.7%,检出限(LOD)为0.009~0.015μg·kg-1,定量下限(LOQ)为0.032~0.049μg·kg-1。该方法简便、快速、准确,可用于精米、玉米和土豆中噻呋酰胺农药残留的确证检测。     

采用CO吸附原位红外光谱研究Pt/TiO_2光催化体系中助催化剂作用

采用CO作为探针分子,将原位透射红外光谱应用于研究助催化剂Pt在Pt/TiO2光催化体系中的作用.实验发现,光照条件下,CO的覆盖度及样品温度没有明显变化,CO在Pt/TiO2上的吸附峰红移11 cm–1,在Pt/Al2O3上的吸附峰没有位移,表明CO在Pt/TiO2上的红移来源于TiO2上的光生电子转移到Pt上,这解释了为什么加入Pt助催化剂可提高光催化产氢活性.     

纯水中有氧条件下Pd/C催化的无配体Suzuki反应简

报道一种在纯水中Pd/C催化的高效Suzuki反应体系,该体系无需除氧,且无外加配体和添加剂,底物普适性广泛,含有亲水或疏水基团的溴代芳烃都能被高效活化. 此外,对部分杂环芳烃与芳基硼酸的偶联反应也有较好的催化效果. 该催化剂可高效循环使用三次,且性能无明显下降.     

Recent Advances of Lanthanide-transition Heterometallic Coordination Polymers

With the improvement of high-tech and emergence of crossing and new fields,lanthanide-transition(Ln–M) heterometallic coordination polymers have attracted much attention of many researchers,which exhibit novel structures and unique properties with potential applications in the nonlinear optical materials,fluorescent materials,superconducting materials,magnetic materials,catalysis,bio-simulation,adsorption and separation,and so on.It is thus necessary to summarize Ln–M heterometallic coordination polymers.According to the transition metal ions,those coordination polymers are divided into six parts to explore the current applications and future developments.     

Synthesis,Crystal Structure and Photoluminescence of a Three-coordinate Ag(Ⅰ) Complex

A three-coordinate Ag(I) complex, [Ag(Mepzpy)(PAr3)]BF4·H2O(1, Mepzpy = 3-methyl-1-(2-pyridyl)pyrazole, PAr3 = tri(o-tolyl)phosphine), was synthesized from the reaction of Ag(CH3CN)4BF4, PAr3 and Mepzpy in CH3 CN at room temperature. The compound was characterized by UV-vis, NMR and X-ray single-crystal structure analysis. It crystallizes in triclinic space group P1 with a = 10.2251(5), b = 10.6014(5), c = 15.7012(5) , α = 92.963(3), β = 92.641(3), γ = 114.647(4)o, V = 1540.6(1) 3, Z = 2, Mr = 676.24, Dc = 1.458 g/cm3, F(000) = 688, μ = 6.187 mm-1, GOOF = 1.038, the final R = 0.0530 and w R = 0.1493 for 6371 observed reflections with I 2σ(I). Compound 1 is ionic. It is composed of a BF4- anion and a [Ag(Mepzpy)(PAr3)]+ cation. The Ag(I) ion adopts a distorted trigonal pyramidal coordination geometry defined by two nitrogen atoms and a phosphorous atom. The complex emits blue luminescence with maximum peaks at 470 nm in solid state at room temperature.