金属镍催化炔基铝与炔溴高效合成对称1,3-二炔化合物

1,3-二炔类化合物是一类重要的有机合成中间体,被广泛应用于药物化学、有机合成及材料科学中.在室温条件下,以乙二醇二甲醚(DME)为溶剂,炔基溴(1 mmol)与炔基铝试剂(1.5 mmol)在Ni(acac)2(5 mol%)/DPPE(10 mol%)催化下进行偶联反应,以中等至优秀的收率得到了多种1,3-二炔烃类化合物.该反应体系对于带不同种类的功能基团的芳炔基铝试剂及炔基溴均有很好的催化活性.而且对于大位阻的α-萘炔及杂环2-噻吩炔也有较好的催化效果.该反应体系简单、催化效率高,不需要其它共催化剂.     

一例基于{PMo_6}单元的杂多钼酸盐的合成、结构及表征

采用常规水溶液合成法成功制备了一例新颖的有机-无机杂化的杂多钼酸盐(C3N2H5)4H[HPMo6O21(O2CC6H4NH2)3]·6H2O (1),并通过X射线单晶衍射、红外光谱、紫外光谱、热失重分析等方法对该化合物的结构进行表征.结构分析表明,化合物1属于三斜晶系,P-1空间群,晶胞参数a=1.319 1(9) nm,b=2.068 8(15) nm,c=2.322 2(16) nm,V=5.701(7) nm3.化合物1包含1个[HPMo6O21(O2CC6H4NH2)3]5-阴离子,4个[C3N2H5]+阳离子,1个H+质子和6个结晶水.化合物1聚阴离子结构中包含一个{PMo6}结构单元,3个对氨基苯甲酸配体通过羧基上的两个氧原子以近乎垂直的方式连接在{PMo6}单元同一侧.紫外光谱研究表明,化合物1在水溶液中6 h内保持相对稳定,能够稳定存在的pH范围大致是7.5～10.5.     

固相萃取/超高效液相色谱-串联质谱测定水果中5种植物生长调节剂残留量

建立了固相萃取/超高效液相色谱-串联质谱(UPLC-MS/MS)同时测定水果中6-苄基腺嘌呤(6-BA)、噻苯隆、氯吡脲、多效唑和烯效唑5种植物生长调节剂残留量的分析方法。水果样品经乙腈提取,NH2固相萃取小柱进行富集、净化,以二氯甲烷-甲醇(92∶8)为洗脱溶液,浓缩定容后,用Waters ACQUITY UPLC BEH C18(50 mm×2.1 mm,1.7μm)色谱柱分离,流速0.3 m L/min,以水-甲醇为流动相梯度洗脱,于UPLC-MS/MS仪多反应监测(MRM)模式测定,基质匹配标准溶液外标法定量。结果表明,5种植物生长调节剂在5~500 ng/m L浓度范围内呈良好的线性关系,相关系数(r2)为0.996 1~0.999 6。在0.004,0.02,0.1 mg/kg加标水平下,方法的回收率为75.6%~110.5%,相对标准偏差(RSD)为1.2%~12.8%,方法检出限(LOD,S/N≥3)为0.001~0.002 mg/kg,定量下限(LOQ,S/N≥10)为0.003~0.006 mg/kg。该方法操作简便、灵敏度高、准确可靠,适用于水果中5种植物生长调节剂残留量的同时测定。     

射频等离子硫钝化GaAs(100)的表面特性

采用射频等离子方法,对Ga As(100)衬底片表面进行干法硫等离子体钝化,旨在得到性能稳定含硫钝化层。样品经过360℃温度条件下的快速热退火,光致发光(PL)测试表明,钝化后的样品PL强度上升了71%。同时,钝化样品的稳定性测试结果表明,样品放置在实验室空气中30 d,其PL强度未出现明显变化,说明Ga As的等离子体干法硫钝化具有较好的性能稳定性。     

Al2O3/SnO2 Co-Nanoparticle Modified Grafted Collagen for Improving Thermal Stability and Infrared Emissivity

Al2O3/SnO2 co-nanoparticles were prepared with a modified sol-gel technique followed by a thermal treatment process. With these co-nanoparticles the grafted collagen-Al2O3/SnO2 nanocomposites were obtained using a supersonic dispersion method. X-ray diffraction, FT-IR analysis, transmission electron microscopy, TGA/DTA and infrared emissivity test were performed to characterize the resulting nanoparticles and nanocomposites, respectively. The Al2O3/SnO2 co-nanoparticles showed a narrow distribution of size between 20-40 nm and could be uniformly absorbed on the tri-helix scaffolds of the grafted collagen without any aggregation. The nanocomposites possessed better thermal stability and substantially lower infrared emissivity than the grafted collagen and Al2O3/SnO2 co-nanoparticles with an increase of degradation temperature from 39 to 210 ℃ and a decrease of infrared emissivity from 0.850 of the grafted collagen and 0.708 of the Al2O3/SnO2 co-nanoparticles to 0.424, which provided a potential application of the nanocomposites to areas such as photoelectronics.     

烯烃配位的过渡金属卡宾配合物的研究XVI:四氟苯并双环[2,2,2]辛三烯三羰基铁的新奇开环反应-新型螯合双烯丙基三羰基铁配合物的合成和结构

四氟苯并双环[2,2,2]辛三烯三羰基铁(C12H6F4)-Fe(CO)3(1)与芳基锂试剂ArLi(Ar=C6H5、o-, m-, p-CH3C6H4、p-CH3OC6H4、p-CiC6H4), 在低温下反应, 生成的酰羰基锂盐中间体用三乙基氧 -四氟硼酸盐(Et3OBF4)在水溶液中于0℃进行烷基化时, 双环烯烃配体开环, 生成组成为(C12H6F4)(CO)2FeC(OC2H5)Ar的螯合双烯丙基二羰基铁配合物(2-7), 配合物5的晶体属单斜晶系, 晶胞参数为;a=16.870(4), b=13.707(4), c=19.361(4)A, β=107.92(2)°.V=4259(1)A^3, Z=8, 空间群为C^62h-C2/c, 最后的偏离因子R=0.0409, Rw=0.0391。     

LOW-FREQUENCY INTERNAL FRICTION STUDY FOR SrBi2Ta2O9 FERROELECTRIC CERAMICS

Low-frequency internal friction (IF) of SrBi₂Ta₂O₉(SBT) ceramics has been measured at temperatures ranging from 293 to 623 K. Two IF peaks, with their locations around 393 K (P1) and 569 K (P2) (f≈1.58 Hz), respectively, are observed. P1 is found to be associated with a relaxation process with activation energy of 0.97 eV and pre-exponential factor of 3.58×10^-14 s. Peak shape analyses reveal that P1 can be well described by a broadened Debye peak with the width parameter β from 2.70 to 2.92. The mechanism responsible for P1 is proposed to be relaxation of oxygen vacancies near domain walls(DWs). P2 is considered to arise from viscous motion of DWs since it shows characteristics of static hysteresis type. Comparisons for the IF behavior between SBT and Pb(Zr, Ti)O₃(PZT) suggest that in SBT oxygen vacancies are much less localized near DWs than that in PZT. This result provides a possible explanation for the weak DW pinning due to oxygen vacancies in SBT.     

1,3,3a,5-四苯基-3a,4,5,11-四氢-3H,6H-1,2,4-三唑并[4,3-d][1,5]苯并二氮杂的合成及晶体结构

通过2,4-二苯基-2,3-二氢-1H-1,5-苯并二氮杂与苯甲酰氯苯腙的[2+3]环加成反应制备了标题化合物,用X射线单晶衍射仪测定了其晶体结构。晶体属正交晶系,空间群为Fdd2.晶胞参数:a=1.7628(4)nm,b=5.7512(12)nm,c=1.0227nm,V=10.368(5)nm³,Z=16,D_c=1.262g·cm^-3,μ=0.075mm^-1,F(000)=4160,1139个可观测衍射点,R=0.0461,R_w=0.0560.     

A FURTHER STUDY OF THE THEORY OF ELASTIC CIRCULAR PLATES WITH NON－KIRCHHOFF－LOVE ASSUMPTIONS

ＡＦＵＲＴＨＥＲＳＴＵＤＹＯＦＴＨＥＴＨＥＯＲＹＯＦＥＬＡＳＴＩＣＣＩＲＣＵＬＡＲＰＬＡＴＥＳＷＩＴＨＮＯＮ－ＫＩＲＣＨＨＯＦＦ－ＬＯＶＥＡＳＳＵＭＰＴＩＯＮＳＣｈｉｅｎＷｅｉ－ｚａｎｇ（钱伟长）ＲｕＸｕｅ－ｐｉｎｇ（茹学萍）（ＳｈａｎｇｈａｉＵｎｉ...     

LIGHT-INDUCED ABSORPTION ENHANCEMENT IN C60 TOLUENE SOLUTION

Absorption enhancement induced by a pump beam of 532 nm in C₆₀ toluene solution has been observed and studied from 560nm to 63Onm, and the absorption cross section of its lowest triplet state has been determined in this wavelength range according to our theoretical model.