Experimental and density functional theory (DFT) studies on the DNA-binding trend and spectral properties of two new Ru(II) complexes: [Ru(L)2(mip)](ClO4)2 (L = 2,9-dmp and 4,7-dmp)

The new ligand 2′-(3″,4″-methylene-dioxyphenyl)imidazo[4′,5′-f] [1,10]phenanthroline (mip) and its Ru(II) complexes [Ru(2,9-dmp)₂(mip)]²⁺ (1) (2,9-dmp = 2,9-dimethyl-1,10-phenanthrolline) and [Ru(4,7-dmp)₂(mip)]²⁺ (2) (4,7-dmp = 4,7-dimethyl-1,10-phenanthrolline) were synthesized and characterized. The binding properties of the two complexes to calf-thymus DNA (CT-DNA) were investigated by different spectrophotometric methods and viscosity measurements. Both 1 and 2 bind to CT-DNA in an intercalative mode, but with different binding strengths. Complex 2 can emit luminescence in the Tris buffer at ambient temperature, however, complex 1 showed no fluorescence emission, neither alone nor in the presence of CT-DNA. The circular-dichroism signal of the dialysate of the racemic complex against CT-DNA suggests that complexes 1 and 2 interact enantioselectively with CT-DNA. Furthermore, complexes 1 and 2 have been found to be an efficient photosensitiser for cracking DNA plasmid. Theoretical calculations for 1 and 2 were also carried out applying the density functional theory (DFT) method and applied to explain some obtained experimental observations.     

White luminescence of Tm-Dy ions co-doped aluminoborosilicate glasses under UV light excitation

Tm³⁺ and Dy³⁺ ions co-doped aluminoborosilicate glasses were prepared in this study. The luminescence properties of the glasses were analyzed. A combination of blue, green, yellow, and red emission bands was shown for these glasses, and white light emission could be observed under UV light excitation. White light luminescence color could be changed by varying the excitation wavelength. Concentration quenching effect was investigated in this paper. Furthermore, the dependence of luminescence properties on glass compositions was studied. Results showed that the luminescence intensity changed with different network modifier oxides, while the white color luminescence was not affected significantly.     

反式-1,4,5,8-四硝基-1,4,5,8-四氮杂萘烷异构体热解机理与稳定性的理论研究

运用密度泛函理论和半经验分子轨道方法,对一系列高能杂环硝胺—反式-1,4,5,8-四硝基-1,4,5,8-四氮杂萘烷异构体的热解机理和稳定性进行了系统地计算研究。在B3LYP/6-31G**和PM3水平上,分别计算了标题物的化学键离解能(BDE)和热解反应活化能(Ea),并根据BDE和Ea数值考察了硝胺取代基对化合物稳定性和热解机理的影响;同时,还详细考察了BDE与Ea、化学键重叠布居数、前线轨道能级以及能隙之间的相关性。结果表明,由BDE、Ea和静态电子结构参数推断的标题物热稳定性和热解机理的结论基本是一致的,N-NO2键均裂是标题物的热解引发步骤,间位取代异构体较对位取代异构体稳定,而邻位取代的异构体稳定性最差。     

HPLC—ICP—MS法对动物源性食品中阿散酸、硝苯砷酸与洛克沙砷残留量的同时测定

建立了动物源性食品中阿散酸(ASA)、硝苯砷酸(NPAA)和洛克沙砷(ROX)的HPLC-ICP-MS分析方法.研究了液相色谱和ICP-MS条件并对提取剂进行了优化.在0 ～100 μg/L范围内阿散酸、硝苯砷酸和洛克沙砷的线性关系良好,线性相关系数均大于0.998; 阿散酸、硝苯砷酸、洛克沙砷检出限分别为2.75、3.85、4.20 μg/kg;保留时间的相对标准偏差(RSD)不大于0.12%.5种样品中3个添加水平的平均回收率为阿散酸86% ～99%,硝苯砷酸79% ～95%,洛克沙砷82% ～98%;相应的RSD分别为2.9% ～8.6%、2.8% ～7.9%、3.3% ～8.1%.     

面包酵母催化不对称还原2,5-己二酮

选用10种面包酵母,研究其对2,5-己二酮的不对称还原特性。筛选出一种酵母S.c No.6,对底物2,5-己二酮有较高的转化活性和对映体选择性。初始底物浓度20 mmol.L-1,经酵母转化48h,2,5-己二醇得率为84.0%,e.e.值94.8%。采用气相色谱-质谱联用技术确认酵母培养液中存在中间产物5-羟基-2-己酮,并推测酵母不对称还原2,5-己二酮的反应分两步进行,首先生成中间产物(S)-5-羟基-2-己酮,而后二次加氢生成(2S,5S)-2,5-己二醇。     

磺酸基锰钛菁基于荧光猝灭对痕量NO2^-离子含量的测定

酞菁化合物是一类非常重要的有机染料,它不仅在可见区有强吸收,而且具有良好的光稳定性、热稳定性和化学稳定性,同时又具有易于合成、成本低廉等优点,越来越令世人瞩目.     

Synthesis and characterization of tercopolymers derived from ε‐caprolactone,trimethylene carbonate,and lactide

A series of tri‐components copolymers with different molar ratios were synthesized via bulk ring‐opening copolymerization of trimethylene carbonate (TMC), L ‐lactide (LLA), and ε‐caprolactone (ε‐CL), using stannous octoate as catalyst. The sequence structure of the tercopolymer chain was characterized by ¹H and ¹³C nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR), and gel permeation chromatography (GPC). The results showed that although block sequence of the corresponding monomers still existed in the tercopolymer chain, the random tercopolymers were ultimately obtained due to the transesterification during polymerization. For the samples TP1 and TP2, longer sequence of LLA existed in the molecular chains. The thermal properties of tercopolymers were investigated by differential scanning calorimetry (DSC) and the mechanical properties of the resulting copolymers were studied by using a tensile tester. The results indicated that the properties of these copolymers could be adjusted by changing the compositions of the copolymers. The resulting tercopolymers are expected to have potential uses as nerve regeneration and other biomedicine materials. Copyright © 2007 John Wiley & Sons, Ltd.     

Littlewood-Paley算子交换子在加权Herz型Hardy空间上的有界性

研究了Littlewood-Paley算子交换子gψ,b在加权Herz型Hardy空间上的性质,并证明了gψ,b在某些条件下是HKa,pq(ω1,ω2)到Ka,pq(ω1,ω2)和HKa,pq(ω1,ω2)到WKa,pq(ω1,ω2)上的有界算子.     

尖晶石型FeMnCuO4的光谱分析及量子化学研究

通过量子化学的密度泛函理论,采用模型化学方法和Gatmion03程序,计算了尖晶石型FeMnCu,4不同模型,分析了它们前线轨道附近的能级分布、轨道组成和可能的跃迁,结合可见紫外光谱、红外光谱的结果,确定了FeMnCuO4中紫外区的主要跃迁是d→p跃迁;可见和近红外区主要是d→d跃迁,振动光谱中高频段主要是铁氧八面体中Fe-O键的振动.