Enantioselective aza-Henry reaction using cinchona organocatalysts

The aza-Henry reaction of imines with nitromethane was promoted by cinchona alkaloids and modified cinchona bases to give optically active β-nitroamines. Various N-protected imines were examined as substrates. N-Boc, N-Cbz, and N-Fmoc protected imines gave the best results in terms of chemical yields and enantioselectivities. After a careful screening of a series of chiral bases, very good enantioselectivities up to 94% ee were obtained using a cinchona-based thiourea organocatalyst under the optimized reaction conditions.     

几种药渣中铁、锌等元素含量的测定及再利用讨论

用原子吸收分光光度法测定几种药渣中铁、锌、铜、锰元素含量,为药渣再利用提供依据。实验表明,不同药渣中铁、锌、铜、锰元素含量不同,同一药渣中各元素含量也不同,且药渣中铁元素含量均高于其它几种元素;实验所测的药渣中平均含铁318.3mg/kg,锌、锰平均含量为34.31和39.13mg/kg。药渣中含有较为丰富的Fe,Zn,Cu,Mn元素,具有再利用价值。     

Amino acids as cations: Tetrachlorocuprates (II) of glycine and β-alanine cations

The effect of glycine and β-alanine, when act as counterions, on the coordination geometry of the tetrachlorocuprates has been investigated.     

四维空间中一类带奇异位势的非局部临界指数问题的正解

本文研究了如下非局部临界指数问题{(-a+b∫_Ω|?_u|~2dx)△u=μu~3+λ|x|β~/u~(q-1),x∈Ω,x∈δΩ,其中Ω?R~4是一个有界光滑区域且0∈Ω,a≥0,b,λ,μ0,1q2,0β2.利用变分方法,我们获得了一些存在性与多重性结果.     

荧光法研究牛血清白蛋白与中性红的相互作用

用荧光光谱、同步荧光光谱、三维荧光光谱和吸收光谱研究了牛血清白蛋白与中性红的结合反应特征,用Stern-Volmer方程和Lineweaver-Burk双倒数函数方程等处理实验数据,得到了15℃时动态猝灭常数kq=5.434×1012L.mol-1.s-1;静态猝灭结合常数KLB=3.300×104L.mol-1,结合位点数n=1.18,根据F ster能量转移原理计算出中性红在牛血清白蛋白上的结合距离r=2.63 nm。     

四配位Co(Ⅱ)构建的螺旋配位聚合物:合成、结构和对CO2的光催化还原

在水热条件下,对映的乳酸衍生物(R)-4-(1-羧基乙氧基)苯甲酸((R)-H_2CBA)和(S)-4-(1-羧基乙氧基)苯甲酸)((S)-H_2CBA)分别与辅助配体1,3-双(2-甲基-1H-咪唑-1-基)苯(1,3-BMIB)以及Co(Ⅱ).反应,合成出一对结构新颖的金属-有机框架化合物{[Co((R)-CBA)(1,3-BMIB)]·H_2O}_n(1-D)和{[Co((S)-CBA)(1,3-BMIB)]·H_2O}_n(1-L)。单晶解析揭示在二维的1-D和1-L中,四配位的Co(Ⅱ).中心分别与乳酸衍生物(R)-H_2CBA(或(S)-H_2CBA)和/或1,3-BMIB一起构建出了3种不同结构的螺旋链。这对螺旋二维化合物在不同pH值的水中有一定的稳定性。紫外-可见吸收光谱显示1-D对420～650 nm范围的可见光有较强的吸收。进一步的Mott-Schottky测试表明1-D是典型的n型半导体。此外其较小的阻抗半径显示其有利于电子传输。在进一步的光催化实验中,1-D实现了光照条件下CO_2转化为CO,反应平均速率为577.8μmol·g~(-1)·h~(-1)。     

Synthesis of aza-diarylmethines via 1,6-conjugate addition/aromatization of para-quinone methides and isatin catalyzed by Et3N

A highly efficient 1,6-conjugate addition/aromatization of para-quinone methides and isatin catalyzed by Et₃Nhas been developed for the synthesis of aza-diarylmethinesin excellent yields (up to 99%). A series of aza-diarylmethines were obtained and scale-up experiment was conducted with excellent results demonstrating the potential applications of this protocol.     

Photon-assisted electronic structure and transport for a quantum dot

This paper investigates theoretically the electronic structure and transport of a two-level quantum dot irradiated under a strong laser field at low temperatures. Using the method of Keldysh equation of motion for nonequilibrium Green functions, it examines the time-averaged density of states and conductance for the system with photon polarization parallel with and perpendicular to the tunnelling current direction respectively. It is demonstrated that, by analysing some numerical examples, more photon sidebands resonance states and multi- and single-photon transitions are found when diagonal matrix elements dominate the interaction, while the electronic transitions due to multiphoton absorption are more or less suppressed when off-diagonal interaction dominates.     

三维Y(Ⅲ)-Ag(Ⅰ)异金属配位聚合物的合成、晶体结构与性质研究

以异烟酸(Hina)和2-磺基苯甲酸(H2L)为配体,在水热条件下与Y(Ⅲ)和Ag(Ⅰ)离子进行协同配位,合成了一个异金属配位聚合物[Y2Ag2L2(ina)4(H2O)2]n(1)。通过X-射线衍射、热重分析、元素分析和红外光谱对其进行表征。X-射线单晶衍射测定其结构为单斜晶系,P21/n空间群,晶胞参数a=0.914 43(3)nm,b=1.378 39(5)nm,c=1.760 76(5)nm,β=102.315(3)°,V=2.168 27(12)nm3,Z=4。它含有一个以羧基O原子桥连的中心对称的四核异金属原子簇[Y2Ag2L2],相邻的原子簇之间通过异烟酸配体相互连接成三维金属有机骨架结构。