微波诱导燃烧法合成类花状ZnO纳米材料及其晶体结构、荧光性质研究

以硝酸锌[Zn(NO3)2.6H2O]和尿素[CO(NH2)2]作前驱体,通过微波诱导燃烧技术可控合成具有不同形貌的ZnO纳米晶体,并用热重分析和差热分析进行了研究。对各种生长条件:微波功率,辐射时间和尿素/Zn2+物质的量的比对ZnO纳米晶体形貌的影响作了分析。结果表明:尿素/Zn2+物质的量的比对ZnO纳米材料的形貌具有显著影响。X衍射图表明合成的ZnO纳米结构呈六角形。傅里叶变换红外光谱图中400~500 cm-1处明显的峰为Zn-O的振动峰。ZnO纳米结构的发光光谱在366 nm的带边发射,因缺陷又由许多可见光发射峰组成。用扫描电子显微镜、透射电子显微镜、选区电子衍射研究了花状ZnO纳米结构的增长机理。本方法仅需几分钟就获得的了ZnO纳米结构。     

4-十二烷氧基苄胺在纳米金微粒合成中的应用

以新型表面活性剂4-十二烷氧基苄胺(C12OBA)构成的C12OBA/正丁醇/正庚烷/丙醛/HAuCl4(aq)反相微乳液作为微反应器,利用微波辐射加热-丙醛还原法制备了C12OBA包覆金纳米微粒;利用透射电镜、傅立叶变换红外光谱仪及X射线衍射仪分析了产物的微观形貌、化学键合特征、晶体结构;并测定了其紫外-可见吸收光谱.结果显示,表面活性剂C12OBA既可参与形成稳定的反相微乳液,又可作为金纳米微粒的良好保护剂.反相微乳液液滴的微小水核以及C12OBA/金的物质的量之比对纳米金微粒的尺寸和形貌起到良好的控制作用.     

微波消解–石墨炉原子吸收法测定化妆品中的铅

建立了微波消解–石墨炉原子吸收光谱法测定化妆品中铅的方法。探讨了样品前处理条件、基体改性剂的选择和优化、石墨炉升温条件等对测定结果的影响。在优化的试验条件下,铅的质量浓度在0~100 ng/mL范围内与吸光度具有良好的线性关系,线性相关系数r=0.9991,检出限为0.33 ng/mL。用该法对5种化妆品中的铅进行测定,加标回收率在95.0%~106.1%之间,测定结果的相对标准偏差不大于3.6%。该方法可应用于化妆品中痕量铅的分析。     

Microwave-assisted conversion of aromatic heterocyclic nitriles to various heterocyclic molecules

Abstract

Dihydroimidazole (3a-c), dihydrooxazole (3d-f), benzoxazole (5a-c), benzothiazole (5d-f) and oxazolopyridine (7a-c) derivatives have been synthesized by condensation of various heterocyclic aromatic nitriles with diamine, aminoalcohal, aminophenol, aminothiophenol, and 3-aminopyridine-2-ol, respectively, under microwave irradiation and under solvent free conditions. This catalyst free and solvent free approach provided heterocyclic compounds in quantitative yields. Time taken for the condensation to occur is < 20 min.     

Synthesis of 3-[6-(2-amino-ethoxy)-3-methyl-5-(3-morpholin-4-yl-propionyl)-benzofuran-2 carbonyl]-chromen-2-one under microwave irradiation conditions

Abstract

(5-Acetyl-6-hydroxy-3-methylbenzofuran-2-carbonyl)-chromene-2-one, paraformaldehyde, and morpholine furnished the mannich base 3-[6-hydroxy 3-methyl-5-(3-morpholin-4-yl-propionyl)-benzofuran-2 carbonyl]-chromen-2-one.This mannich base is irradiated with various chloro-substituted amines afforded 3-[6-(2-amino-ethoxy)-3-methyl-5-(3-morpholin-4-yl-propionyl)-benzofuran-2 carbonyl]-chromen-2-one in good yields.     

Muscle oxygenation measurement in humans by noninvasive optical spectroscopy and Locally Weighted Regression

We have developed a method to make real-time, continuous, noninvasive measurements of muscle oxygenation (Mox) from the surface of the skin. A key development was measurement in both the visible and near infrared (NIR) regions. Measurement of both oxygenated and deoxygenated myoglobin and hemoglobin resulted in a more accurate measurement of Mox than could be achieved with measurement of only the deoxygenated components, as in traditional near-infrared spectroscopy (NIRS). Using the second derivative with respect to wavelength reduced the effects of scattering on the spectra and also made oxygenated and deoxygenated forms more distinguishable from each other. Selecting spectral bands where oxygenated and deoxygenated forms absorb filtered out noise and spectral features unrelated to Mox. NIR and visible bands were scaled relative to each other in order to correct for errors introduced by normalization. Multivariate Curve Resolution (MCR) was used to estimate Mox from spectra within each data set collected from healthy subjects. A Locally Weighted Regression (LWR) model was built from calibration set spectra and associated Mox values from 20 subjects using 2562 spectra. LWR and Partial Least Squares (PLS) allow accurate measurement of Mox despite variations in skin pigment or fat layer thickness in different subjects. The method estimated Mox in five healthy subjects with an RMSE of 5.4%.     

Microwave and Ultrasound Irradiation‐Assisted Synthesis of Novel Disaccharide‐Derived Arylsulfonyl Thiosemicarbazides

The synthesis of 1‐arylsulfonyl‐4‐(1′‐N‐hepta‐O‐acetyl‐β‐lactosyl)thiosemicarbazides by reaction of hepta‐O‐acetyl‐α‐D‐lactosyl isothiocyanate with substituted phenylsulfonyl hydrazines has been shown to occur in less than 1 min under microwave activation and 8 min under ultrasound irradiation at room temperature. It is noteworthy that when ultrasound and microwaves (MW) were utilized, a cleaner reaction accompanied with higher yields was observed.     

Microwave‐Promoted Acid‐Catalyzed Rearrangement of Morphinans—A High‐Yield Synthesis of R(−)‐Apomorphine

The microwave‐promoted acid‐catalyzed rearrangement of morphine (1), codeine (2), and thebaine (3) was investigated. In all cases, a significant improvement in the yields were achieved compared to the traditional techniques. R(‐)‐Apomorphine (4), which is a clinically important dopamine agonist, was synthesized from morphine (1) in 75% yield.     

Microwave‐Assisted Construction of Diaryl Ethers Directly from Arylmethanesulfonates as Convenient Latent Phenols with Aryl Halides

The microwave‐assisted synthesis of diaryl ethers directly from aryl halides and arylmethanesulfonates, which as latent phenols obviate a deprotection step prior to the S_NAr reaction, in the presence of Cs₂CO₃ is described. The reaction time was very short (6–9 min), and good to excellent yields (53–90%) with the wide substrate scope were achieved without any catalyst.