海虾虾青素的提取工艺及含量测定

以新鲜海虾为材料,采用单因素实验研究了提取溶剂、料液比、提取温度、提取时间、提取次数对虾青素提取效果的影响,用紫外可见分光光度法测定了不同部位虾青素的含量,比较了煮熟虾壳与新鲜虾壳中虾青素的含量变化。结果表明,乙酸乙酯是提取虾青素的最适溶剂,最佳提取条件是:料液比1∶2(g∶mL)、提取温度60℃、提取时间3h、提取2次。虾壳中虾青素含量最高,煮熟后虾壳中虾青素含量明显降低。     

紫外-可见分光光度法分析层状双氢氧化物缓蚀剂释放机制

制备了插层缓蚀剂的层状双氢氧化物(LDHs),并通过分光光度法研究了插层层状双氢氧化物的释放机制。X-射线衍射、傅里叶红外光谱分析和扫描电镜表明,2-巯基苯并咪唑阴离子成功插层到了LDHs的层间。通过在氯化钠溶液中的释放测试,证明层状双氢氧化物具有快速释放的能力。可见,智能自修复涂层具有切实的可行性,能够使设备的使用寿命得到有效延长,具有一定的开发潜力和应用前景。     

N-乙酰-L-酪氨酸甲酯偶氮衍生物的合成及紫外可见光谱学性质

以N-乙酰-L-酪氨酸甲酯为原料,合成了6个新型的偶氮衍生物,通过IR、~1HNMR、~(13)CNMR、EI-MS和元素分析进行了表征。考察了所合成化合物的偶氮式-腙式互变异构以及溶剂和pH对紫外可见光谱的影响。结果表明,溶质-溶剂相互作用会影响化合物在不同溶剂中的λ_(max)发生微小的变化,分子内和分子间氢键的作用影响较大。溶液pH会直接影响偶氮式和腙式的平衡构成,随着pH的增加,偶氮式在偶氮式-腙式互变异构平衡中的比例逐渐降低。这些偶氮化合物有望成为一类潜在的pH指示剂。     

Spectrophotometric investigations and computational calculations of prototropic tautomerism and acid-base properties of some new azo dyes

The prototropic tautomerism in four novel azo compounds derived from pyrazolo[1,5-a]pyrimidin-7(4H)-one was intensively examined. Tautomeric structures which result from annular and azo-hydrazone tautomerism were exposed to semiempirical and density functional theory (DFT) calculations, allowing the recording of structural parameters, physicochemical properties and equilibrium constants to be recorded. The values of the equilibrium constants determined among the most stable forms clearly showed that compounds 1 and 2 co-exist in the NH and hydrazone forms. However, NH tautomers were strongly preferred to other forms in compounds 3 and 4. The observed electronic absorption bands were assigned and compared with the predicted transitions using a time-dependent DFT method (TDDFT). In all solvents employed, except for DMF and acetonitrile, compounds 1 and 2 exhibited azo-hydrazone tautomerism. However, the ionized species were predominant in highly polar solvents for compounds 3 and 4. In DMF, all the investigated dyes exist either in acid-base equilibrium or in the ionized form depending on the molecular structure. Hence, the values of the ionization constant (K_ion) and Gibbs free energy (ΔG) of the equilibrium existing in solution were calculated. In addition, the pK_a values of the investigated dyes were determined spectrophotometrically.     

2，5-双【2-（1-正丁基-1H-吡咯-2-基）乙烯基]1，4-二辛氧基苯的合成与性质

文章以对二甲苯和吡咯甲醛为初始原料合成二吡咯化合物2,5-双【2-（1-正丁基-1H-吡咯-2-基）乙烯基]1,4-二辛氧基苯,利用核磁氢谱对其结构进行了确认,并对其紫外．可见光谱、荧光光学性能进行了初步研究。     

Theoretical and Experimental Spectroscopic Analysis of Cyano-Substituted Styrylpyridine Compounds

A combined theoretical and experimental study on the structure, infrared, UV-Vis and ¹H NMR data of trans-2-(m-cyanostyryl)pyridine, trans-2-[3-methyl-(m-cyanostyryl)] pyridine and trans-4-(m-cyanostyryl)pyridine is presented. The synthesis was carried out with an efficient Knoevenagel condensation using green chemistry conditions. Theoretical geometry optimizations and their IR spectra were carried out using the Density Functional Theory (DFT) in both gas and solution phases. For theoretical UV-Vis and ¹H NMR spectra, the Time-Dependent DFT (TD-DFT) and the Gauge-Including Atomic Orbital (GIAO) methods were used, respectively. The theoretical characterization matched the experimental measurements, showing a good correlation. The effect of cyano- and methyl-substituents, as well as of the N-atom position in the pyridine ring on the UV-Vis, IR and NMR spectra, was evaluated. The UV-Vis results showed no significant effect due to electron-withdrawing cyano- and electron-donating methyl-substituents. The N-atom position, however, caused a slight change in the maximum absorption wavelengths. The IR normal modes were assigned for the cyano- and methyl-groups. ¹H NMR spectra showed the typical doublet signals due to protons in the trans position of a double bond. The theoretical characterization was visibly useful to assign accurately the signals in IR and ¹H NMR spectra, as well as to identify the most probable conformation that could be present in the formation of the styrylpyridine-like compounds.     

驱蚊蚊帐的制备和表征

采用氨基丙基三乙氧基硅烷偶联剂处理涤纶蚊帐,然后将处理后的蚊帐浸泡在添加溴氰菊酯悬浮液的聚氨酯胶粘剂乳液中,室温固化得到表面含有溴氰菊酯的蚊帐,该蚊帐具有驱蚊效果。利用紫外可见吸收光谱可以非常简便地测定蚊帐中溴氰菊酯含量。     

苏氨酸三肽与DNA相互作用的研究

利用紫外-可见光谱法和凝胶电泳法研究了在人体正常的生理环境下苏氨酸三肽与DNA的相互作用。结果表明:苏氨酸三肽可与DNA发生相互作用,二者的作用模式为沟槽结合,结合常数为K=6.4×105L·mol-1,最大结合数n=7.04。     

Structural, optical and EPR studies on ZnO:Cu nanopowders prepared via low temperature solution combustion synthesis

Cu (0.1 mol%) doped ZnO nanopowders have been successfully synthesized by a wet chemical method at a relatively low temperature (300 °C). Powder X-ray diffraction (PXRD) analysis, scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Fourier transformed infrared (FTIR) spectroscopy, UV-Visible spectroscopy, Photoluminescence (PL) and Electron Paramagnetic Resonance (EPR) measurements were used for characterization. PXRD results confirm that the nanopowders exhibit hexagonal wurtzite structure of ZnO without any secondary phase. The particle size of as-formed product has been calculated by Williamson-Hall (W-H) plots and Scherrer's formula is found to be in the range of ∼40 nm. TEM image confirms the nano size crystalline nature of Cu doped ZnO. SEM micrographs of undoped and Cu doped ZnO show highly porous with large voids. UV-Vis spectrum showed a red shift in the absorption edge in Cu doped ZnO. PL spectra show prominent peaks corresponding to near band edge UV emission and defect related green emission in the visible region at room temperature and their possible mechanisms have been discussed. The EPR spectrum exhibits a broad resonance signal at g ∼ 2.049, and two narrow resonances one at g ∼ 1.990 and other at g ∼ 1.950. The broad resonance signal at g ∼ 2.049 is a characteristic of Cu²⁺ ion whereas the signal at g ∼ 1.990 and g ∼ 1.950 can be attributed to ionized oxygen vacancies and shallow donors respectively. The spin concentration (N) and paramagnetic susceptibility (χ) have been evaluated and discussed.     

一种新型三足席夫碱稀土配合物的合成及与DNA作用方式的研究

合成了一种新型三足席夫碱和它的四种稀土配合物,通过元素分析、红外光谱、紫外光谱、差热-热重、核磁共振和摩尔电导率对配合物进行了表征,推测了配合物的可能结构。应用紫外可见光谱法和电化学方法对配合物与ct-DNA之间的相互作用进行了研究,结果表明,配合物与ct-DNA之间存在插入作用;配合物CV测试随扫描速度增加,其氧化峰电位Ep发生正移,氧化峰电流Ip随扫描速度的增加呈线性增加趋势,并且Ip与扫描速率平方根(v1/2)呈良好线性关系,表明配合物在GCE上的电化学氧化反应是一个受扩散步骤所控制的过程。