DFT/TDDFT study on the electronic structures and optoelectronic properties of several red-emitting osmium(II) complexes with different P^P ancillary ligands

The ground and excited state geometries of several red-emitting phosphors (N^N)(2)Os(P^P) [where N^N = 5-(1-isoquinolyl)-1,2,4-triazoles, P^P = bis(dimethylphosphino)methylene(dmpm) (1); P^P = cis-1,2-bis-(dimethylphosphino)ethene(dmpe) (2); P^P = 1,2-bis(dimethylphosphino)benzene(dmpb) (3); P^P = 1,2-bis(dimethylphosphino)naphthalene(dmpn) (4); P^P = 1,2-bis(dimethylphosphino)-4-cyano-benzene(dmpcb) (5)] have been investigated by using the density functional theory (DFT) methods. The calculated results indicate that, for the studied complexes, the electron-transporting performance is better than the hole-transporting performance. The alteration of cis-P^P ancillary ligands with different conjugation lengths and substituents has an impact on the optoelectronic properties of these complexes, especially the electron-withdrawing group -CN in 5. The calculated energy gaps are nearly the same for complexes 1 to 4 (3.34 eV), while for 5, the HOMO and LUMO energies are lowered and the energy gap increases (3.42 eV). The absorption of 1 is red shifted, while that of 5 is blue shifted compared with the absorptions of 2, 3, and 4, which have similar absorptions. Complexes 2, 3, and 4 have almost identical emission wavelength 699 nm, while 1 (715 nm) and 5 (735 nm) are red shifted. The calculated electron affinities and reorganization energies indicate that complex 5 is the easiest for electron injection and has the best electron-transporting performance.     

Qualitative and quantitative analyses of Epimedium wushanense by high-performance liquid chromatography coupled with diode array detection and electrospray ionization tandem mass spectrometry

A new HPLC-DAD-ESI-MS(n) method was developed for rapid separation, characterization and quantitation of flavonoids in Epimedium wushanense, a popular Chinese herbal medicine. For qualitative identification, a total of 37 compounds were characterized from the underground and aerial parts of E. wushanense. Among them, 28 compounds were prenylated flavonoids, and 23 were confirmed by comparing with reference standards. For quantitative analysis, 12 major flavonoids including kaempferol glycosides, desmethylicaritin glycosides, and icaritin glycosides were simultaneously determined by HPLC/UV. Samples were separated on a Waters Symmetry C(18) column at 35 °C eluted with a gradient three-component mobile phase of acetonitrile, methanol, and water containing 0.03% v/v formic acid. All the flavonoids showed good linearity (r(2) ≥0.9997). The recoveries varied from 92.6 to 106.1% at three concentration levels. This method was applied to the determination of 20 samples of different geographical sources, harvesting time, and plant parts. Contents of the predominant flavonoid, epimedin C, ranged from 1.4 to 5.1% in aerial parts and 1.0 to 2.8% in underground parts. The methods established in this paper were simple and reliable and could be used for the quality control of E. wushanense.     

二甲基甲酰胺中四种钕盐的电导

通过电导测量研究了四种钕盐：Nd(CF3SO3)3、Nd(ClO4)3、Nd(NO3)3和NdCl3在极性非质子溶剂DMF中的电导性质.利用线性拟合方法求得在25 ℃下Nd(CF3SO3)3和Nd(ClO4)3的极限摩尔电导率分别为278.8和 280.7 S•cm2•mol－1.用间接方法求得Nd(NO3)3 与NdCl3 的极限摩尔电导率分别为297.2和287.3 S•cm2 •mol－1.在25～65 ℃温度范围内，Nd(CF3SO3)3和Nd(ClO4)3的电导率随温度呈线性变化. Nd(NO3)3和NdCl3的电导行为表现出明显的离子缔合.     

双波长薄层紫外可见光谱电化学测定多巴胺

多巴胺 (DA)和抗坏血酸 (AA)的吸收光谱在 2 0 0～ 30 0nm内重叠严重 ,但在电化学氧化状态下 ,DA的氧化产物在 2 10 ,30 0和 4 80nm有强吸收峰 ,AA的氧化产物在 2 0 0～ 4 0 0nm范围内吸收较弱且呈光滑平缓的斜坡。在此基础上 ,利用自行设计的长光程薄层光谱电化学池建立了一种双波长光谱电化学法测定DA。测定条件为 pH 6 .2的磷酸盐缓冲液 (PBS) ,0 .6V (vs.Ag/AgCl)电极电位 ,双波长 318/ 2 93nm ,线性范围为 4 .0× 10 - 6 ～ 2 .0× 10 - 4mol·L- 1,检出限为 2 .0×10 - 6 mol·L- 1。对 6 .2 0× 10 - 5mol·L- 1DA进行 11次平行测定 ,平均相对偏差为 2 .6 %。与文献报道的吸光光度法相比 ,该法具有较高的灵敏度和选择性 ,较为有效地消除了AA的干扰 ,回收率在 91.8%～ 10 0 .8%之间 ,结果满意     

以[Eu(PBrBA)3phen]和[Eu(PCBA)3phen]为探针的温敏漆制备及其性能对比

以氧化铕(Eu_2O_3)、对氯苯甲酸(PCBA)、对溴苯甲酸(PBrBA)和菲咯啉(phen)为原料制备了菲咯啉对氯苯甲酸铕[Eu(PCBA)_3phen]、菲咯啉对溴苯甲酸铕[Eu(PBrBA)_3phen]两种探针分子,并将这2种探针分子掺杂在甲基丙烯酸甲酯(MMA)中,以过氧化苯甲酰(BPO)为引发剂,制得Eu(PCBA)_3phen/PMMA和Eu(PBrBA)_3phen/PMMA温敏漆样品。利用红外光谱仪、扫描电子显微镜、紫外-可见分度光度计和荧光光谱仪对探针分子的组成结构、发光性能、形貌和温敏漆的温度敏感性进行了测试分析,研究了不同配体对探针分子发光性能和温敏漆性能的影响。结果表明,Eu~(3+)分别与对氯苯甲酸(PCBA)和对溴苯甲酸(PBrBA) 2种主配体配位,并且第二配体菲咯啉(phen)均参与了配位,成功合成了2种配合物。2种配合物均发出Eu~(3+)的特征荧光,其中以PBrBA为主配体的菲咯啉铕三元配合物具有更好的发光性能。此外,基于这2种探针分子制备的温敏漆在50～90℃范围内均具有温度猝灭性能,以Eu(PCBA)_3phen为探针制成的温敏漆温度敏感性更强。     

Determination of Pesticide Residues in Fruit and Vegetables by High-Performance Liquid Chromatography–Tandem Mass Spectrometry with Multivariate Response Surface Methodology

Multivariate response surface methodology optimization using Placket–Burman and Box–Behnken designs were respectively used for the screening and optimization of significant factors for liquid chromatography–tandem mass spectrometry. Consequently, the optimized instrument successfully improved the sample preparation protocol and the method was validated. However, modified QuEChERS dispersive solid phase extraction coupled with ionic liquid-based dispersive liquid–liquid microextraction were used for the determination of multi-pesticide residues in fruit and vegetable samples. The analysed samples were jackfruit, strawberries, cucumber, pears, and carrots. The resulting linearity range (5–400?µg/kg) and regression coefficient (>0.99) results were satisfactory. The 94.2 and 95.8% accuracy (89–138%) and precision (0–25%) results were satisfactory and within the recommended ranges (≤20%) and (70–120%), respectively. The limits of detection (0.01–0.54?µg/kg) and quantitation (0.03–1.79?µg/kg) were excellent. The matrix effects (≤?87%) for all analysed samples were not significant. The estimated measurement uncertainties (≤27%) were within the acceptable range (≤50%). Justifiably, the response surface methodology optimized instrument and sample treatment techniques were reliable and convenient for multi-pesticide residue determination in various fruits and vegetables.     

Approaches to unsaturated analogues of nucleosides comprising four- and six-membered rings

Unsaturated nucleoside analogues 21, 22, 46, and 54, comprising four- and six-membered rings, were synthesized using two different approaches. The 2-benzyloxycycloalkanones 23a and 23b served as starting materials for both methods. Conversion to methylenecyclobutanes 29a and 29b was followed by addition of bromine via pyridinium perbromide to give vicinal dibromides 30a and 30b. Reaction of 29a with Br2 gave a ring-contracted cyclopropane derivative 31. Alkylation-elimination of adenine with 30a gave bromoalkene 32 as the major product and adenine-containing unsaturated derivatives 33, 34, and 35 as minor components. Vicinal dibromide 30b gave the Zaitsev cyclohexene 45 as the only product. Epoxidation of 29a and 29b afforded oxiranes 36a and 36b which were used in alkylation of adenine to furnish hydroxy derivatives 37a, 37b, 38a, and 38b. Beta-elimination via mesylates 39a and 40a using tBuOK/DMF gave Z- and E-methylenecyclobutanes 34 and 35. With an excess of base the E-bis-methylenecyclobutane 41 was obtained. Mesylation of cyclohexane derivatives 37b and 38b gave the Z- and E-N6-mesylated product 48. By contrast, the N6-benzoyl derivatives 49 and 50 afforded O-mesyl intermediates 51 and 52. Beta-elimination gave both Hofmann and Zaitsev products 53 and 45. O-Debenzylation of 34 and 35, 45, and 53 afforded analogues 21, 22, 46, and 54. The E-isomer 22 was also obtained by hydroboration procedure from E-bis-methylenecyclobutane 41.     

担载材料对TiO2薄膜光催化活性的影响

TiO_2 nanocrystalline films were prepared on glass, ITO and p-Si substrates. Degradation of Rhodamine B was used to assess the photocatalytic activity of the films. It was found that photocatalytic activity of TiO2 films on ITO and p-Si are higher than that on glass, and the film grown on ITO is the best. In addition, crystalline phases and surface morphology of TiO_2films were also affected by different substrates. Surface Photovoltage Spectra was used to analyze surface states and energy levels of the films. Separation of photogenerate electrons and holes was promoted due to matching of the energy levels between TiO_2 films and ITO as well as p-Si. High photocatalytic activity was then obtained because more photogenerate electrons and holes took part in photocatalytic reaction on TiO_2 surfaces.     

Effects of monoclonal antibody anti-EGF receptor on human nasopharyngeal carcinoma cell and other tumor cells

Three anti-EGF receptor MoAbs were used in these studies. Administration of MoAbs 3 and 176 inhibited tumor formation in nude mice by CNE-2, a poorly differentiated nasopharyngeal carcinoma cell line and A431, an epidermoid carcinoma cell line. When the same MoAbs were used in treatment against HeLa, a cervical carcinoma, tumor growth was not affected. The number of EGF receptors and apparent dissociation constants for 125I-EGF on CNE-2 and A431 was 1.3 x 10(5)/cell (Kd 7.7 x 10(-8) mol/L) and 1.4 x 10(6)/cell (Kd 2.4 x 10(-9) mol/L), respectively. Both MoAbs 3 and 176, capable of competing with EGF for receptor binding, showed significant tumor growth inhibition. MoAb 101 was incapable of blocking the binding of EGF to its receptor, and not as effective as MoAbs 3 and 176 in tumor growth inhibition. Our observation is that the MoAb anti-EGF receptor is cytostatic rather than cytocidal, in vitro against CNE-2 and A431.     

配合物[Li(THF)_2]_2(μ—Cl)_4[(η~5—CH_3C_5H_4)Nd·THF]的合成及其晶体结构

环戊二烯基希土氯化物是一类合成希土有机配合物的重要前身。尽管在1980年前没能成功地合成含轻希土元素的这类配合物,但目前已发现,采用具有较大体积的取代环戊二烯做配体,如C_5Me_5H,C_5H_3〔Si(CH_3)_3〕_2H,C_5Me_4C_3H_7H和桥联的配体(C_5H_4)_2(CH_2)_3H_2都可得到相应的取代环戊二烯基轻希土氯化物。控制LnCl_3和CpNa的反应摩尔比也可以成功地得到这类轻希土的环戊二烯基氯化物。