Catalytic allylic transfer reactions of functionalized aldehydes promoted by BINOL-Ti(IV) with synergistic reagent

Practical and efficient catalytic asymmetric allylic transfer reactions of tin reagents promoted by BINOL-Ti[OCH(CF₃)₂]₂ complex by the utilization of t-BuSBEt₂ are successful with a variety of functionalized aldehydes containing ketone, aldehyde, ester, amide, or carbamoyl functionality and affords products in high levels of enantioselectivity.     

双甘肽稀土配合物溶液结构的13C和1H NMR研究

~(13)C and ~1H NMR technique was used to study the interaction of Gly-Gly with heavy lanthanide cations Dy~(3+), Ho~(3+), Er~(3+), Tm~(3+) and Yb~(3+) in aqueous solution. The stability constants for the 1:1 and 1:2 complexes of Gly-Gly with Ho~(3+) and Yb~(3+) were determined from the titration curves of chemical shift versus concentration ratio of lanthanide to Gly-Gly. The solution structure of the Ln-Gly-Gly complex was analyzed based upon the ~(13)C and ~1H lanthanide-induced shifts and the results show that in the complex Gly-Gly is coordinated to the lanthanide ion through the carboxyl oxygens with the backbone of the ligand in an extended state.     

Pore Structure Analysis of Porous Particles by Equivalent Model

Starting from Wheeler's composite theory, which takes both the multilayer adsorption and the capillary condensation into consideration, and assuming the equivalent cylindrical model, we have deduced a strict and relatively simpler formula for the calculation of pore size distribution by solving the integral equation directly. The formula is more convenient for application because of its recursion form. Following the same line of reasoning and using the mean value theorem of definite integrals under different conditions, we have unified the equations of Barrett-Joyner-Halenda, Dubinin, Cranston-Inkley, Dollimore-Heal and Roberts. A table of parameters which is required in the calculation is given. Besides the adsorption of nitrogen, the adsorption with water vapor as the adsorbate is investigated and the corresponding empirical equation of adsorption thickness is given.     

Crystal Structure of Dimethylamine 3,5-Dinitrobenzoic Acid Organic Adduct

1 INTRODUCTION Nonlinear optics (NLO) is at the forefront of cur- rent researches because of its importance in provi- ding the key functions of frequency shifting, optical modulation, optical switching, optical logic and op- tical memory for the emerging …     

Synthesis and Crystal Structure of Glycin·3,5-Dihydroxybenzoic Acid

The title compound glycin·3,5-dihydroxybenzoic acid (GDB) has been synthesized and characterized by single-crystal X-ray analysis. It crystallizes in orthorhombic, space group Pca21 with a = 25.513(10), b = 4.668(2), c = 9.150(4)(A), Z = 4, V = 1089.8(8)(A)3, C9H13NO7, Mr = 247.20, Dc = 1.507 g/m3, μ(MoKα) = 0.132 mm-1, F(000) = 520, R1 = 0.0322 and wR2 = 0.0611 for 885 observed reflections (I > 2σ(I)). The title compound is a 1:1 molecular complex of glycin and 3,5-dihydroxybenzoic acid, which is linked by O-H…O and N-H…O hydrogen bonds to form a three-dimensional framework. Test of SHG (second harmonic generation) indicates that NLO generation of the crystal is higher than that of KDP.     

Cl+C2H6→HCl+C2H5反应的准经典轨线研究

用三原子模型的准经典轨线方法研究了Ｃｌ与Ｃ２Ｈ６（ｖ＝０，ｊ）的反应。计算结果表明，反应产物ＨＣｌ的角度分布基本上为各向同性，其振动分布处于基态，与实验结果相一致。对反应轨线的研究表明，该反应为一直接反应，而且反应碰撞在低及高的碰撞参数下的机理不一样，在低碰撞参数下反应碰撞是直接完成的，产物ＨＣｌ以向后散射为主，转动基本上是冷的，但比高碰撞参数下的热。在高的碰撞参数下则生成短寿命的碰撞复合物，产物     

Synthesis and Crystal Structure of a Novel Two-dimensional Supramolecular Complex Ni（C6H7N）2（SCN）2（H2O）2

1 INTRODUCTION Supramolecular chemistry is based on the notion of creating novel structural and functional extended systems using noncovalent interactions between prefabricated molecular or ionic building blocks[1]. More recently, the design of supramolecular architec- tures by self-assembly of small building blocks has become a major research area[2, 3] due to their poten- tial applications in many fields such as selective clathration[4, 5], molecular recognition[6, 7], catalysis[8, 9] a…     

A unique cyanide-bridged three-dimensional (3-D) copper(II)-copper(I) mixed-valence polymer containing 1-D water tapes with cyclic pentamer units

A unique cyano-bridged copper(II)-copper(I) mixed-valence polymer, {[Cu(3)(CN)(4)(H(2)O)(3)](H(2)O)(2)}(n) (1), has been prepared and structurally determined by X-ray diffraction. The cyanide anions with (mu(2),eta(2)) and (mu(3),eta(2)) bridging modes connect the copper centers into a complicated zeolite-like 3-D network. Of further interest, coordinated and lattice water molecules in this structure form 1-D hydrogen-bonded water tapes consisting of linked cyclic pentamer clusters.     

273.15 K下Li2B4O7-LiCl-H2O体系热力学性质的等压研究及离子作用模型

用等压法研究了273.15 K下Li₂B₄O₇-LiCl-H₂O体系不同质量摩尔浓度分数的等压平衡浓度和水活度; 计算了LiCl和Li₂B₄O₇混合盐溶液的渗透系数等热力学性质. 用273.15 K下的实验数据对Pitzer离子相互作用模型进行了参数化研究, 拟合求取了273.15 K下Pitzer离子相互作用参数, 用获得的参数计算了LiCl和Li₂B₄O₇在Li₂B₄O₇-LiCl-H₂O体系中的活度系数. 273.15 K下由相应的Pitzer模型计算的渗透系数值与实验结果一致. 这对完善含锂、硼盐湖卤水体系的热力学模型具有重要意义.     

BiFeO3空间选择性光化学还原Ag及光催化活性

采用溶胶-凝胶法和光还原沉积法制备出Ag改性的纳米BiFeO₃粒子,对复合材料进行了FESEM、XRD、XPS、FTIR、UV-Vis/DRS等分析和表征。考察了波长365nm以上的光照下,铁磁性材料的空间选择性光化学反应对复合材料的结构、形貌以及光谱性质的影响。以罗丹明B为模拟污染物,考察了纳米Ag-BiFeO₃粒子的可见光光催化活性以及稳定性。结果表明：通过光化学沉积,不仅增强了BiFeO₃在200~800nm光照下的响应,而且抑制了光腐蚀现象,提高了BiFeO₃的稳定性。在波长大于400nm的光照射12h后单纯纳米BiFeO₃粒子对罗丹明B脱色率约为74%,而Ag-BiFeO₃复合材料6h后约为90%,并且重复使用3次后光催化效果基本不变。