Synthesis of indenoindene-fused α-methylene-γ-butyrolactones via a tandem intra- and intermolecular Friedel-Crafts reaction

An efficient synthesis of indenoindene-fused α-methylene-γ-butyrolactones was carried out via a tandem intra- and intermolecular Friedel-Crafts reaction from the spiro-lactone, which can be easily prepared from ninhydrin by indium-mediated Barbier reaction of cinnamyl bromide.     

α-Amination and the 5-exo-trig cyclization reaction of sulfur-containing Schiff bases with N-phenyltriazolinedione and their anti-lipid peroxidation activity

Triazolinedione quenches efficiently the 1,2-dipoles from Schiff bases of glycine esters which are formed via a [1,2-H]-prototropic shift of their α-hydrogens, and affords the respective α-aminated products in good yields. Competition experiments show a stabilization of the 1,2-dipole from the sulfide substituent. 5-exo-trig cyclization of N-PhTAD with Schiff bases of other amino acids gave triazolines. The antioxidative and lipoxygenase inhibitory activities of the novel synthesized compounds were studied.     

Orientation effect on the electronic transport properties of C24 fullerene molecule

The transport properties of the cage-like molecule depend on its orientation between the electrodes, but the investigation on the mechanism has not been found. Using first-principle density-functional theory (DFT) and non-equilibrium Green’s function (NEGF) formalism for quantum transport calculation, we study the electronic transport properties of C₂₄ fullerene molecule with different orientations in Au–C₂₄–Au two-probe system. The effects of k-point sampling on the Brillouin zone are explored. Our results show that the negative differential resistance of C₂₄ molecule is found in such a system and can be tuned by the molecule's orientation in the two-probe system. We also proposed a mechanism for it. The I–V characteristic under bias voltage is determined. The present findings could be helpful for the application of the C₂₄ molecule in the field of single molecular devices or nanometer electronics.     

Synthesis and structural characterization of heteroleptic Cu(I) complexes with α-diimines derived from pyridinyliminobenzoic acids

The synthesis and molecular and electronic structure of heteroleptic univalent copper compounds [Cu(L)(PPh₃)X] are reported where X is a halide and L represents 3-pyridinylimino, 4-pyridinylimino or 3,5-dipyridinylimino-substituted benzoic acid, hereafter abbreviated as L1, L2, and L3, respectively. The crystal structures of two iodide and one bromide complexes are described. All compounds are hydrogen-bonded dimers. The electronic excitation spectra of the compounds are dominated by intraligand bands of ligands while characteristic MLCT transitions are observed at 430–480?nm. No emission is observed from the compounds either in the solid state or in solution; on the contrary a photodecomposition is observed resulting in triphenylphosphane ligand elimination and formation of halogen-bridged dimmers.     

Electronic and thermodynamic properties of α-Pu2O3

Based on density functional theory+U$\text{density functional theory}+U$ calculations and the quasi-annealing simulation method, we obtain the ground electronic state for α-Pu₂O₃ and present its phonon dispersion curves as well as various thermodynamic properties, which have seldom been theoretically studied because of the huge unit cell. We find that the Pu–O chemical bonding is weaker in α-Pu₂O₃ than in fluorite PuO₂, and subsequently a frequency gap appears between oxygen and plutonium vibration density of states. Based on the calculated Helmholtz free energies at different temperatures, we further study the reaction energies for Pu oxidation, PuO₂ reduction, and transformation between PuO₂ and α-Pu₂O₃. Our reaction energy results are in agreements with available experiment. And it is revealed that high temperature and insufficient oxygen environment are in favor of the formation of α-Pu₂O₃.     

Effect of ultrasound on the activity and conformation of α-amylase,papain and pepsin

The effect of ultrasound on the activity of α-amylase, papain and pepsin was investigated and the mechanism of the effect was explored by determining their conformational changes. With the irradiation of power ultrasound, the activity of α-amylase and papain was inhibited, while the activity of pepsin was activated. According to the analysis of circular dichroism, Fourier transform infrared and fluorescence spectroscopy, the π_o → π¹ amide transitions and secondary structural components, especially β-sheet, of these three enzymes were significantly influenced by ultrasound. The tryptophan fluorescence intensity of the three enzymes was also observed to be affected by sonication. Furthermore, it was found that the pepsin molecule might gradually be resistant to prolonged ultrasonic treatment and recover from the ultrasound-induced damage to its original structure. The results suggested that the activity of α-amylase, papain and pepsin could be modified by ultrasonic treatment mainly due to the variation of their secondary and tertiary structures.     

蓝宝石(α-Al_2O_3:Fe~(3+))体系基态分裂与局域晶格畸变的研究

2002年Scholz和Buzaré对蓝宝石晶体中Fe3+离子的基态分裂重新进行了EPR实验测量和研究,他们的初步分析表明在蓝宝石晶体中Fe3+离子的6A1基态分裂有可能同时与两个方向的畸变角(θ和φ)有关.本文采用对角化d5组态在C3点群对称下的252×252完全能量矩阵的方法,对蓝宝石晶体中Fe3+离子的光谱和EPR谱进行了系统的研究.计算结果表明蓝宝石体系中Fe3+离子的6A1基态分裂确实将明显依赖于两个方向的畸变角θ和φ,这一理论结果与Scholz和Buzaré等的实验相符合.同时,通过拟合Fe3+离子在蓝宝石体系中的实验光谱和EPR参量,确定了蓝宝石晶体中(FeO6)9团簇局域晶格畸变角θi的范围.     

一类α次殆星形映照的偏差定理

近年来,双全纯凸(准凸)映照的偏差定理的研究已经获得一些可喜成果,但目前星形映照的偏差定理研究成果还较少.利用α次殆星形映射的增长估计,我们得到了C~n中开单位球B~n上一类α次殆星形映射的偏差估计.对复Banach空间单位球B和Reinhard域Ω_p1,…,p_n,可得到同样的结论,正如猜想的一样.     

模糊随机环境下的连续型变额生命年金

采用模糊随机理论,构建连续支付型变额生命年金模型.假定利率为三角模糊数,死亡率为随机变量.结合精算理论,给出了连续支付型变额生命年金精算现值的期望、方差以及分布函数和分位数的模糊表达式.最后,通过实证分析计算出一个在养老保险中常见的生命年金的相关值,验证模型的可行性.