2-(苯并噻唑-2-基)-5-(N,N-二乙基氨基)苯酚衍生物的合成及其对H2S的识别

以4-N,N-二乙基氨基水杨醛为原料,制备了2-(苯并噻唑-2-基)-5-(N,N-二乙基氨基)苯酚衍生物(探针L),并对其结构进行了表征。在DMSO/PBS(体积比3∶7,pH=7.4)溶液中,探针L具有高选择性并可荧光"关-开"识别H_2S,在365nm紫外灯照射下,由无荧光变成蓝色荧光。实验表明,探针L识别H_2S的检测限为2.05×10~(-6)mol/L,pH适用范围为6～9,可用于检测实际水样中的H_2S。     

Preparation and crystal structure of Nb6.74 Ta5.26S4 – a new compound in the ternary system Ta?Nb?S

Nb_6.74Ta_5.26S₄ has been prepared by high temperature techniques. The crystal structure has been determined from single crystal X-ray diffraction data (R/R_w = 0.0588/0.0655). The compound crystallizes in the orthorhombic space group Pnma with unit cell dimensions a = 959.11 (26) pm, b = 336.37 (10) pm, and c = 3282.51 (74) pm. The orthorhombic cell contains four formula units. Its structure is similar to that of Nb-rich sulfides, rather than to that of Ta-rich sulfides. The metal coordinations are capped distorted cubic prisms and pentagonal prisms while the coordinations of sulfur are capped trigonal prisms.     

Synthesis, Characterization and Fluorescence of a One-dimensional Cadmium（Ⅱ） Compound Involving Covalent and Hydrogen Bonds

1 INTRODUCTION The rational design and synthesis of new metal- organic coordination polymers have generated con- siderable interest in supramolecular chemistry and material science owing to their intriguing structural diversities and potential applications as functional materials[1～3]. Molecular self-assembly has been pro- ved to be an efficient way to construct various inte- resting coordination polymers[4～6]. The coordina- tion covalent bond, hydrogen bond or other mole- cular interact…     

小分子配体诱导合成N,N-二苄基二硫代氨基甲酸镉(II)配合物及晶体结构

4,4'-联吡啶与二苄基二硫代氨基甲酸镉配合物[Cd(DBTC)₂]₂ (1)反应得到加合物[Cd(DBTC)₂(4,4'-bipy)] (2) (DBTC＝N,N-二苄基二硫代氨基甲酸), 通过晶体结构分析及红外光谱等研究其结构与性质. 结果表明: 引入小分子配体会破坏[Cd(DBTC)₂]₂ (1)的二聚结构, 加入吡啶则得到单核的吡啶加合物[Cd(DBTC)₂py] (3), 而引入4,4'-联吡啶后其结构变为新型的一维链状结构的配位聚合物2, 这种结构在二硫代氨基甲酸金属配合物中少见报道. 也比较了不同配体如吡啶及4,4'-联吡啶对Cd(II)及Zn(II)配合物结构的影响.     

Effect of selenium oxidation state on cadmium translocation in chamomile plants

Syntheses and spectral characteristics of cadmium(II) compounds (CdSeO₄, CdSeO₃, and Cd(NCSe)₂(nia)₂) containing selenium in oxidation states (VI), (IV), and (-II) are described. In Cd(NCSe)₂(nia)₂, nicotinamide (nia) and selenocyanate anions are bonded to Cd atom as N-donor monodentate ligands. Nicotinamide is coordinated through the ring nitrogen atom. The effects of these selenium compounds as well as Cd(NCS)₂(nia)₂ on the growth and Cd accumulation in roots and shoots of hydroponically cultivated chamomile plants (cultivar Lutea) were studied. In the applied concentration range (12–60 μmol dm⁻³) Cd(NCS)₂(nia)₂ affected neither the length nor the dry mass of roots and shoots. Other compounds applied at 24 μmol dm⁻³ and 60 μmol dm⁻³ significantly reduced dry mass of roots and shoots. Selenium oxidation state in the cadmium compounds affected Cd accumulation in plant organs as well as Cd translocation within the plants, which was reflected in the values of bioaccumulation (BAF) and translocation factors (S/R). Cd amount accumulated by shoots was lower than that in the roots. The highest BAF values determined for Cd accumulation in shoots were obtained with CdSeO₄. Substitution of S with Se in the Cd(NCX)₂(nia)₂ (X = Se or S) caused an increase of Cd translocation into the shoots. Presented at the XVIIIth Slovak Spectroscopic Conference, Spišská Nová Ves, 15–18 October 2006.     

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.     

The effect of H2S concentration on the corrosion behavior of API 5L X-70 steel

This work presents electrochemical data measured during the corrosion of API 5L X-70 pipeline steel immersed in aqueous environments containing dissolved H₂S. Three different electrolyte were used: a 3 wt% NaCl solution containing 100, 650 and 2,550 ppm of H₂S respectively. The corrosion of steel is described by means of electrochemical impedance spectroscopy. The electrochemical data obtained from the steel monitoring are presented in terms of Nyquist plots. The influence of the total H₂S concentration as well as the effect of temperature on the corrosion of API 5L X-70 steel were also studied. In the presence of H₂S the R_ct values decrease as the H₂S concentration increases.     

Crystallographic evidence of hexacoordination at phosphorus via intramolecular coordination of donor groups on phosphane and phosphane sulphide

The X-ray structure analysis of bis(8-dimethylamino-l-naphthyl)phenylphosphane (3) and of the corresponding sulphide 4 has revealed hexacoordination at phosphorus in both cases, the N … P separations being less than the sum of the van der Waal radii. Furthermore, in both cases the overall geometry corresponds to a distorted bicapped tetrahedron. The optimum geometry calculated for 4 via the program developed by Autodesk (MM + method) suggests that the structure of the molecule is a function not only of steric requirements but also of electronic effects.     

Effect of hydrogen bonding of solvent on the thermodynamic stability of cadmium ethylenediamine complexes

Changes in the stability of the cadmium(ii) ethylenediamine complexes in mixed water—DMSO solvents were studied by pH-metry and calorimetry. Complex cations [Cd(en)]²⁺, [Cd(en)₂]²⁺, and [Cd(en)₃]²⁺ are formed in aqueous solutions, and the [Cd(en)₄]²⁺ complex with a partially dentate ligand is stable in DMSO. An increase in the DMSO content in a solvent increases the stability of the complexes. The maximum increase in logK is observed for coordinatively saturated compounds. The thermodynamics of complexation is discussed from the viewpoint of solvation approach. Principal differences in the influence of aqueous-alcohol and aqueous-aprotic solvents on the stability of the metal amino complexes were revealed. Protolytic solvents exert a destabilizing effect on the multiligand complexes, because the coordination sphere is involved in H bonding.     

高折光指数光学树脂的合成——相转移法合成不饱和硫醇酯单体的条件控制

采用正常的低温相转移催化（ＰＴＣ）和反滴碱溶液ＰＴＣ法分别合成了含硫双烯ＭＥＳＤＭＡ和单烯ＭＥＰＳＭＡ．１Ｈ ＮＭＲ分析证明ＭＥＳ中的杂质主要是由原料ＴＤＧ引入的．对含单个巯基的ＭＥＰＳ的正常ＰＴＣ酯化接枝双键，因存在巯基和不饱和双键的加成反应而导致失败．作者最终得到了折光指数在１６２５以上的ＭＥＳＤＭＡ／ＭＥＰＳＭＡ共聚物．