μ-phenoxo-bridged binuclear copper(II) complexes

Summary Two -phenoxo-bridged binuclear copper(II) complexes, [Fsal(GG)₂Cu₂Cl₃]·H₂O (1) containing an exogenous chloride-bridge and [Fsal(GG)₂Cu₂(OH)](ClO₄)₂·H₂O (2) containing an exogenous hydroxide-bridge, where {Fsal(GG)₂ = 2,6-bis[N-(acetylglycine)-imino-methylene]-4-methylphenol}, were synthesized. The complexes were characterized be several spectroscopic methods. According to variable temperature magnetic susceptibility measurements (4–300 K), the hydroxide-bridged complex (2) has a weak antiferromagnetic spin exchange integral (J =- 23.6 cm), while the chloride complex (1) has an unusual weak ferromagnetic spin exchange integral (J = + 30.9 cm); both complexes have similar optical spectra in the aqueous solutions.     

Hydrolysis of 2-aminoethanethiolsulfate ions

The kinetics of the acid catalyzed hydrolysis of 2-aminoethanethiolsulfate (AETS) ions were investigated. The dependence of the hydrolysis rate constant on acidity and temperature was determined. The hydrolysis rate equation can be expressed as where H_o is the Hammett acidity function. The rate constant, k, can be expressed as The pK_a's for the compound were measured and literature value of pK_a was found to be in error. The values determined in this study are pK_a1 < ?0.5 and pK_a2 = 9.1 ± 0.1. General acid catalysis of the hydrolysis reaction was found not to proceed to a significant degree. © 1994 John Wiley & Sons, Inc.

1 This article is a US Government work and, as such, is in the public domain in the United States of America.

     

Density and momentum dependence of the coupling strengths for scalar and vector fields

The collision term has been deduced based on the effective Lagrangian in addition to the mean-field. We propose the momentum- and density-dependent coupling strengths for scalar and vector fields. The saturation properties of nuclear matter, the experimental data of the energy-dependent optical potential and the mean free path in the nuclei can be reproduced simultaneously. The in-mediumn–n cross section has also been calculated for different densities and energies, our results are consistent with Dirac-Brueckner-Hartree-Fock calculations.Supported by National Natural Science Foundation of China     

Large-scale synthesis of tube-like ZnS and cable-like ZnS-ZnO arrays: Preparation through the sulfuration conversion from ZnO arrays via a simple chemical solution route

Arrayed structures are desirable for many applications, but the fabrication of many material arrays remains a significant challenge. As a prominent II-VI semiconductor, large-scale arrayed ZnS structure has not been easily fabricated. Here, we introduce a simple structure conversion route for the synthesis of novel arrayed structures, and large-scale tube-like ZnS structure arrays and cable-like ZnS-ZnO composite arrays were successfully prepared through sulfuration conversion from arrayed rod-like ZnO structure based on a hydrothermal method at low temperature. XRD, EDS, SEM, TEM and PL are used to confirm the formation of the novel arrayed structure and trace the conversion process. The results show that the conversion ratio can be conveniently tailored by the reaction time, and the PL properties of the obtained materials can be adjusted through the conversion ratio. Especially, the cable-like structure holds the PL properties of both ZnO and ZnS structures. This simple solution method can be further extended to the preparation of other semiconductor sulfide and selenide, and can amplify the application field of large-scale arrays of semiconductors.     

Synthesis and Structureof［（C_2H_5）_4N］［Mo_3（μ_3－O）（μ－Cl）_3（μ－CH_3CH_2COO）_3Cl_3］

ＳｙｎｔｈｅｓｉｓａｎｄＳｔｒｕｃｔｕｒｅｏｆ［（Ｃ_２Ｈ_５）_４Ｎ］［Ｍｏ_３（μ_３－Ｏ）（μ－Ｃｌ）_３（μ－ＣＨ_３ＣＨ_２ＣＯＯ）_３Ｃｌ_３］ＺｈｕａｎｇＨｏｎｇ－Ｈｕｉ；ＷｕＤｉｎｇ－Ｍｉｎｇ；ＨｕａｎｇＪｉａｎ－Ｑｕａｎ；ＨｕａｎｇＪｉｎ－Ｌ...     

低碳烃芳构化过程中HZSM－5催化剂结炭规律的研究

用ＧＣ、ＴＰＯ－ＧＣ、ＮＨ＿３－ＴＰＤ和ＴＥＭ等方法，测定了丙烷在ＨＺＳＭ－５沸石上芳构化过程中，催化剂的活性、结炭量、结炭Ｃ／Ｈ比、酸密度等，考察了催化剂的结炭量与其它参数之间的关系。结果表明，在反应温度为８７３Ｋ，进料空速ＷＨＳＶ＝５ｈ￣（－１）时，丙烷在ＨｚＳＭ－５上的结炭首先发生在沸石晶体的外表面的活性中心上（结炭量１．８％之前）；结炭量为１．８～３．４％时，主要在孔道交叉点结炭；结炭量在３．４～５．７％时，孔道已有受限或阻塞现象发生，导致一些富氢的结炭物在孔道内生成。     

An order-disorder transition in Sr2IrD5: Evidence for square pyramidal IrD5 units from powder neutron diffraction data

Neutron diffraction data have been collected on a powdered sample of Sr₂IrD₅ over a range of temperatures. The compound, which is cubic at room temperature, has been found to exhibit a gradual transformation to a tetragonal phase in the temperature range 200-140 K. As a result of the transition, deuterium atoms which randomly occupy sixfold positions in the cubic phase, become tetragonally ordered. A small fraction of the cubic phase remained untransformed at 4.2 K. Both the cubic and tetragonal structures are consistent with square pyramidal IrD₅ units with average Ir---D distances of 1.714 and 1.718 Å, respectively. Agreement factors, R₁, for the two structural analyses are 3.44 and 4.94%.     

糖和H_8-BINOL衍生的单齿亚磷酸酯配体的合成及其Rh催化α-脱氢氨基酸不对称氢化反应的研究

由单糖(如果糖、葡萄糖和甘露醇)和H8-2,2'-联萘二酚出发设计和合成了的六个手性单齿亚磷酸酯配体,研究了其铑配合物催化α-脱氢氨基酸甲酯的不对称氢化反应,在1%mol催化剂量和0.12MPaH2下,产物的对映选择性最高达到90.6%e.e.     

Highly effective and recyclable dendritic ligands for the enantioselective aryl transfer reactions to aldehydes

[reaction: see text] A series of chiral pyrrolidinylmethanol-based dendritic ligands were synthesized for application in enantioselective aryl transfer reactions to aldehydes with the (ArBO)3/ZnEt2 system in up to 98% ee.