Synthesis of （2R,4R）—2—N—tert—Butyloxycarbonyl Amino—4,5—epoxido—valeric Acid Methyl Ester

The stereoselective synthesis of (2R,4R)-2-N-tert-butyloxycarbonyl amino-4,5-epoxido-valeric acid methyl ester 8,which is the key intermediate for the synthesis of (2′S,2R)-3-trans-nitrocyclopropyl-alanine,was first accomplished.     

Carbonyldinitrosyltris(fluorosulfato)tungstate(II) and ‐Molybdate(II) Anions: Synthesis,Spectroscopy, and Density Functional Theory Calculations

Carbonyldinitrosyltris(fluorosulfato)tungstate(II) and ‐molybdate‐(II) anions, [fac‐M(CO)(NO)₂(SO₃F)₃]^? (M=W, Mo), which are novel weakly coordinating anions that contain a metal carbonyl/nitrosyl moiety, have been generated in fluorosulfonic acid and completely characterized by multinuclear NMR, IR, and Raman spectroscopy as well as ESI mass spectrometry. ESI MS measurements performed for the first time on a superacidic solution system unambiguously reveal the formation of the monoanionic, mononuclear W and Mo complexes formulated as [M(CO)(NO)₂(SO₃F)₃]^? (M=W, Mo). Multinuclear NMR spectroscopic studies at natural abundance and ¹³C and ¹⁵N enrichment clearly indicate the presence of one CO ligand, two equivalent NO ligands, and two types of nonequivalent SO₃F^? groups in a 2:1 ratio. The IR and Raman spectra reveal that the two equivalent NO ligands have a cis conformation, thus indicating a fac structure. Density functional calculations at the B3LYP level of theory predict that these anions have a singlet ground state (¹A′) with a C_s symmetry along with C–O and N–O vibrational frequencies that are in agreement with the experimental observations. Mulliken population analysis shows that the monovalent negative charge is dispersed on the bulky sphere, the surface of which is covered by all the negatively charged O and F atoms with charge densities much lower than SO₃F^?, suggesting that [fac‐M(CO)(NO)₂(SO₃F)₃]^? (M=W, Mo) are weakly nucleophilic and poorly coordinating anions.     

1—酰基—4—氯环己烷与取代芳烃的区域与立体选择性反应

从环己烯合成了１－酰基－４－氯环己烷，发现在其在ＡｌＣｌ３催化与苯，氯苯，溴苯等优先生成反式１－芳基－４－酰基环己烷，与联苯反应时选择性较差。     

单分散二氧化钛超微粒子的制备

以四丁氧基钛为原料，采用溶胶－凝胶法制备了超微二氧化钛粉末．改变热处理气氛、升温速率、水与四丁氧基钛的摩尔比以及溶剂，分别得到７ｎｍ球形单相锐钛矿以及四方形（４０ｎｍ×１０ｎｍ）、球形（４４ｎｍ）的主相金红石超微粒子．     

13C NMR studies of molecular relaxation processes in polar fluids

A study of the dynamical molecular structure of a dilute polar fluid is reported, in which ¹³C spin-lattice relaxation times of decanol in deuterated cyclohexane are presented for the individual carbon atoms, and the results are discussed in the context of viscosity data of decanol in alkane systems. The two techniques provide complementary information about the mobility of the alcohol chains and the onset of multimer formation, which is also pertinent to the dynamics of electron solvation in the same systems.     

Separation of Dyes from Aqueous Solutions by Paper Adsorption

Separation of the dyes methyl violet, methylene blue, and congo red from aqueous solutions by paper capillary permeation adsorption method was studied using paper. Nearly 100% of the investigated dyes could be separated under the optimum conditions. The effect of pH on the separation efficiency was studied in particular. At pH 5–9, 1.3–11, and 7–11, the maximum separation was achieved for methyl violet, methylene blue and congo red, respectively. The effects of dye concentration and some foreign ions on the separatability were examined. Moreover, the selective separation of some dyes was attempted by elution with chemical reagents.     

Underpotential Deposition Study and Determination of Bismuth on Gold Electrode by Using Voltammetry

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AIBN/SmCl3/乳酸体系催化甲基丙烯酸甲酯的反向原子转移自由基聚合

利用稀土金属化合物三氯化钐(SmCl3)和二氯化钐(SmCl2)之间的单电子转移反应,以AIBN/SmCl3/乳酸作为反向原子转移自由基聚合(ReverseATRP)的催化体系,成功地实现了甲基丙烯酸甲酯(MMA)的反向ATRP,并考察了温度、溶剂和组分比对聚合反应的影响.MMA在该体系中的聚合反应是一级反应,所得PMMA的分子量与单体转化率成正比,聚合物的分子量分布较窄(Mw/Mn<1.5),具有活性聚合的特征.     

A new gas chromatographic stationary phase: Polysiloxane with β-cyclodextrin side chain for the separation of chiral and positional isomers

Summary A new stationary phase [bikis(2,6-di-O-pentyl-3-O-hex-6-enyl)-pentakis(2,6-di-O-pentyl-3-O-methyl)-β-CD-polysiloxane] was synthesized and successfully applied in GC for the separation of chiral and achiral isomers. It possesses high column efficiency and exhibits excellent separation ability for disubstituted benzenes. Some typical enantiomers and optical isomers are well separated. The separation behavior of this new phase is characterized and discussed.     

C60大量、快速分离和电喷雾电离质谱检测

本文用配合沉淀和活性炭吸附相结合的方法，从高级富勒烯含量较高的混合物中，大量、快速分离Ｃ６０，并用电喷雾电离质谱对分离产物进行检测