Solution Structure and Behavior of Benzophenone-based Achiral Bisphosphine Ligands in Noyori-Type Ru（Ⅱ）-Catalysts

We herein report on solution structural studies of Ru^Ⅱ catalysts （3a, 9） composed of achiral bisphosphine ligands （4, 8） and the enantiopure 1,2-diphenylethylenediamine （DPEN）. Complete chiral induction from enantiopure （R,R）-DPEN to achiral bisphosphine ligand 3a was observed in solution, with the complex adopting a single, stable and non-fluxional （even at 70 ℃） configuration. The coordination of the C=O moiety in 4 to the cationic Run center is considered to be of key importance in providing the higher thermodynamic and kinetic rotation barrier for the flexible bisphosphine ligand in the complex. The obtained enantioselectivity （91% enantiomeric excess） and sense of chiral induction in the hydrogenation of acetophenone were found to be solely dependent on the chirality of the 1,2-diamine. Consistent with the hydrogenation product, the （R,R）-DPEN induces a M-conformation （fight-handed） chirality for flexible phosphine ligand 4 in the complex, resulting in a 2,2-configuration about the Ru^Ⅱ center.     

Synthesis of Pharmaceutical Intermediates by Toluene Benzylation over Heteropoly Acids on Different Support

Selective formation of pharmaceutical intermediates like diphenylmethane, dimethyl- diphenylmethane, benzyl toluene and benzoic acid by liquid phase, toluene benzylation with benzyl chloride as a benzylating agent, was systematically studied over plane clay (K-10, montmorillonite), plane H-Beta, plane MFI structured titanosilicate (TS-1) and heteropoly acids [HPA, namely dodeca-tungstophosphoric acid [H3PO4.12WO3.xH2O] (TPA), dodeca-molybdo phosphoric acid ammonium salt hydrate [H12Mo12N3O40P aq] (DMAA), sodium tungstate hydrated purified [Na12WO4.2H2O] (STH)] supported on clay, H-beta and TS-1. The 20%TPA/Clay, 30%TPA/H-Beta and 30%TPA/TS-l, were observed to be the best catalyst samples over plane clay, plane H-Beta and plane TS-1. The catalyst samples are compared with respect to benzyl chloride conversion and selectivities for diphenylmethane, dimethyl-diphenylmethane, benzyl toluene and benzoic acid. The reaction follows the pseudo-first order rate power law model. The apparent rate constants are calculated and compared with the reported ones.     

Chemical Reduction of CO2 to Different Products during Photo Catalytic Reaction on TiO2 under Diverse Conditions： an Overview

The chemical reduction of CO_2 remains a challenge with respect to the reversal of the oxidative degradation of any organic materials.The conversion of CO_2 into useful substances is essential in developing al- ternative fuels and various raw materials for different in- dustries.This also aids in preventing the continuous rise in tropospheric temperature due to the green house effect of CO_2.In this article an overview of the growth taken place so far in the field of CO_2 chemical reduction is pre- sented.The discussion comprises of photochemical meth- ods for the development of different products,viz.CO, CH_3O_H and CH_4,through chemical reduction of CO_2. This includes the use of photo catalysts,mainly TiO_2, and the role of a hole scavenger(such as 2-propanol)for this purpose.     

Investigation of Aconitine-type Alkaloids from Processed Tuber of Aconitum carmiechaeli by HPLC-ESI-MS/MS~n

Introduction Aconitine-type alkaloids isolated from the roots of Aconitum carmiechaeli show a potential toxicity and a broad spectrum of bioactivity[1-4].On the basis of the C8-substituent of C19-diterpenoid skeleton,aconitine-type alkaloids can be divided into diester-diterpenoid alkaloids(DDAs),monoester-diterpenoid alkaloids(MDAs),and lipo-alkaloids(Fig.1).     

CROSS-LINKING OF AROMATIC POLY（THIOETHER）S

A novel cross-linking process using two high molecular weight aromatic poly(thioether)s,which were synthesized by the reactions of 4,4′-thiobisbenzenethiol with 4,4′-difluorobenzophenone and 4,4′-difluorodiphenylsulfone,respectively, and commercially available lower molecular weight poly(p-phenylene sulfide)was investigated.These reactions were carried out in bulk by the addition of silver tetrafluroborate andα,α′-dibromo-p-xylene at 190℃over a period of 45 min. Furthermore,the same procedure could be modified to cross-link compression-molded films of these three polymers.The thermal and solubility behaviors of these polymers before and after cross-linking reactions,are presented.     

STUDY ON THE PROPERTIES OF BLEND OF NATURAL RUBBER LATEX/METHYL METHACRYLATE GRAFTED RUBBER LATEX BY GAMMA RADIATION

Natural rubber latex(NRL)and methyl methacrylate(MMA)grafted rubber latex were blended in different ratios and irradiated at various absorbed doses by gamma rays from Co-60 source at room temperature.The tensile properties, swelling ratio and permanent set were measured.The maximum tensile strength and modulus at 500% elongation were obtained at an absorbed dose of 8 kGy.Modulus increases from 6.99 MPa to 9.87 MPa for an increase in proportion of MMA grafted rubber from 40% to 60% in the blend at similar absorbed dose.Elongation at break and swelling ratio decrease with increasing absorbed dose as well as the MMA grafted rubber content in the blends.The decreasing trend of permanent set is high up to 5 kGy absorbed dose,and beyond that dose,it becomes almost flat.     

Volumetric and Refractive Index Behaviour of α-Amino Acids in Aqueous CTAB at Different Temperatures

Densities （ρ） and refractive indices （nD） of glycine （Gly）, DL-alanine （Ala）, DL-valine （Val） （0.02, 0.04, 0.06, 0.08, and 0.10 mol·L^-1） in 0.005 and 0.008 mol·L^-1 aqueous cetyltrimethylammonium bromide （CTAB） have been measured at 298.15, 303.15, 308.15, and 313.15 K. The density data have been utilized to calculate apparent molar volumes （φv）, partial molar volumes （φv^0）, at infinite dilution and partial molar volumes of transfer φv^0 （tr） of amino acids. The refractive index data have been used to calculate molar refractivity （Rr,） of amino acids in aqueous cetyltrimethylammonium bromide. It has been observed that φv^0 varies linearly with increasing number of carbon atoms in the alkyl chain of amino acids, and hence, was split to get contributions from the zwitterionic end groups （NH3^＋ COO^-） and methylene group （CH2） of the amino acids. The behaviour of these parameters has been used to investigate the solute-solute, solute-solvent interactions and the effect of cetyltrimethylammoniuln cation on these interactions,     

一种有效的气相色谱手性固定相—2，6-O-二戊基-3-O-三氟乙酰基-β-环糊精

一种新的气相色谱手性周定相——2,6-O-二戊基-3-O-三氟乙酰基-β-环糊精合成并用于分离手性化合物的对映体。对一百余个手性化合物的分离结果显示,它是一种适合于较低温度使用的、手性分离选择性好的固定相。当柱温不高于150℃时,柱的稳定性和分离的重复性均较好。     

CLIMATIC CHANGE SINCE LITTLE ICE AGE RECORDED BY DUNDE ICE CAP

The climatic change since the Little Ice Age recorded in the Dunde Ice Cap is presentedin this paper. There have been three cold periods and three warm periods since 1400AD.Among them, the coldest one was in the 17th century. Many evidences verified the three coldand warm variations recorded in the Dundc Ice Cap. But it was found from the comparison between the Dunde Icc Cap climatic record and thewinter temperature record in Shanghai that there was a temporal dfference in climatic changebetween East China and West China. The general trend is that the cooling and warmingprocesses in West China were earlier than that in East China. In the Dunde Ice Cap, it isnow in an anomalous warm period, while it is not as warm as in Dunde Ice Cap recordaccording to the winter temperature in Shanghai. In addition to the possible cause of temporaldifference in climatic change between West China and East China, another possible cause isthat the greenhouse effect of CO_2 may already be recognizable in the Dunde Ice Cap a     

轻稀土B-15-C-5联吡啶三元配合物

合成了稀土(Ln=La—Eu)硝酸盐与苯并-15-冠-5和2,2’-联吡啶的三元配合物,并培养出La-配合物的单晶,测定了的分子结构和晶体结构。经元素分析确定其化学组成为Ln(NO_3)_3·bipy·2H_2O·B-15-C-5。晶体属单斜晶系,空间群为P2_1/n。晶胞参数:a=11.951(6),b=18.181(7),c=14.754(5);β=96.19(3)°;V=3187.0,Z=4,D_c=1.637g/cm~3。最后偏离因子R=0.035。