氨基酸-银反应的光化学特点

氨基酸与银的反应是一个不借外加能量热力学上即可进行的过程,但当引入光之后,可改变反应速率.研究发现:Soret带出现吸收所需光照度的大小顺序为Asp Ag(I)>Thr Ag(I)>Tyr Ag(I)>Lys Ag(I),对于Cys Ag(I)体系,Cys的α羧基氧、α氨基的氮与银(I)结合时光照有利于反应的进行,而S原子与银(I)结合与光照度几无关系.此反应是光助化学反应.     

单个Ag(Br,Ⅰ)微晶颗粒内碘含量及其分布的实验观察

本文用透射扫描电子显微镜与X射线能谱仪相结合,观察分析了几种不同Ag(Br,I)乳剂中单个Ag(Br,I)微晶颗粒内的碘含量及其分布,得到了一些初步结果。这种方法所提供的信息对于研究乳剂制备条件对Ag(Br,I)微晶结构与性能的影响等是很有用的。     

Ag(Ⅰ)-phen-TPPS_4水溶液体系中显色反应的研究

本文提出了在碱性介质中,基于Ag(I)-phen-TPPS_4配合物的生成而建立高灵敏度测定Ag(I)的分光光度法。配合物的最大吸收波长为438nm,摩尔吸光系数为136×10~5L.mol~(-1).cm~(-1)。Ag(I)的浓度在0～0.4μg/mL范围内符合比尔定律。Ag(I)的最低检出限为8.8ng/mL。配合物的组成为Ag(I):phen:TPPS_4=1:2:1。方法简便、快速,应用于生产感光乳胶的废水中微量银的测定,获得较满意的结果。     

2,5-巯基-1,3,4-硫代二氮唑自组装金电极测定银(I)

制备了2,5-巯基-1,3,4-硫代二氮唑(DMTD)自组装单分子层修饰金电极,用电化学阻抗谱进行了表征,研究了Ag(I)在该电极上的电化学行为并用差分脉冲阳极溶出伏安法对其进行了测定。结果表明,DMTD/Au电极能显著提高Ag(I)测定的灵敏度和选择性,Ag(I)浓度在9.4×10-7～8.0×10-6mol/L范围内,氧化峰电流与Ag(I)呈现良好的线性关系,检出限为2×10-7 mol/L。该自组装电极可用于水样的测定。     

Luminescent Cu(I) and Ag(I) coordination polymers: Fast phosphorescence or thermally activated delayed fluorescence

Three luminescent Cu (I) and Ag (I) coordination polymers based on donor-acceptor motif ligands are reported.Two Cu (I) coordination polymers both exhibit fast phosphorescence,which another Ag (I) coordination polymer present TADF photoluminescence emission at room temperature.     

伯胺N_(1923)硝酸盐从硫代硫酸盐溶液中萃取银(Ⅰ)的机理

本文研究了伯胺N_(1923)硝酸盐(RNH_3NO_3)从硫代硫酸盐溶液中对Ag(I)的萃取。结果表明,Ag(I)同时以AgS_2O_3~-和Ag(S_2O_3)_2~(3-)两种形式萃入有机相。     

Synthesis and Crystal Structure of Binuclear Silver(I) Complex with 2-nitro-(2-pyridylsulfanylmethyl)benzene

1 INTRODUCTION Metallosupramolecular species with metal-metal interactions have been designed and synthesized due to their potential applications as functional materi- als[1]. For Ag(I) coordination compounds, short Ag(I) –Ag(I) separations have been found in many bi- and polynuclear complexes[2~4], and these short metal- metal distances have been attributed to the ligand ar- chitecture[5, 6]. Thus, the rational design of bi- and polynuclear Ag(I) complexes must recognize the in- here…     

1,2-二(2-胺基苯氧基)乙烷银配合物的合成与晶体结构

本文采用配体1, 2-二(邻氨基苯氧基)乙烷(L)分别与AgPF6, AgCF3SO3, AgNO3和AgSbF6 进行配位反应,依次得到了四个配合物1 [Ag2(L)2(PF6)]、2 [Ag2(L)2(CF3SO3)2]、3 [Ag(L)NO3]n 和4 [Ag(L)2SbF6]n,并通过FTIR、元素分析、以及X射线单晶衍射等对配合物的结构与组成进行了表征。单晶衍射结果表明,配合物1和2为双核银(I)配合物,3和4为银(I)的配位聚合物。配合物1具有穴状结构,2经Ag?Ag键桥连两个配体形成扭曲的非平面结构。聚合物3的结构为一维(1D)“之”字链,4具有三维(3D)多孔的结构框架。在四个配合物结构中,相应的抗衡阴离子均未参与Ag(I)进行配位作用。     

常温常压下β沸石改性吸附剂脱除噻吩类硫的研究

在合成不同硅铝比Naβ沸石的基础上，采用固相离子交换方法制备了Cu(I)、Ag(I)离子改性的β沸石系列吸附剂。样品的结晶度和BET比表面积有所降低，XRD表征结果表明，所制备的样品保持了结构的完整性，随着硅铝比的增加，Naβ样品的BET比表面积增加。Cu(I)、Ag(I)离子的引入使样品的红外骨架振动峰向低波数移动，与相同硅铝比的Naβ沸石相比，吸附剂的BET比表面积有所降低。对模型油的静态吸附结果表明,硅铝摩尔比为25时Cu(I)β吸附性能最好，模型油中硫的质量分数降到10×10－6以下，脱除率达到95％，Ag(I)β次之，脱除率达到87％。常温常压下固定床动态吸附穿透实验得到Cu(I)β、Ag(I)β的穿透硫容分别为0.144mmol/g和0.132mmol/g。     

双层六辐轮状簇合物[Ag（MBI）]6的合成、表征及晶体结构

合成了簇合物[Ag(MBI)]6(MBI为2-巯基苯并咪唑),通过元素分析、红外光谱、紫外-可见光谱和核磁共振氢谱等对其进行了结构表征,并用X射线衍射法测定了其晶体结构。该簇合物的晶体属于单斜晶系,C2/c空间群;晶胞参数:a=19.2865(8),b=18.1398(5),c=24.8614(10),β=108.698(4)°,V=8238.8(5)3,Dc=1.243g/cm3,Z=4,F(000)=2976.0,μ=1.577mm-1,S=1.010,(Δ/σ)max=0.003,R1=0.0524,wR2=0.1612[I>2σ(I)]。[Ag(MBI)]6的核心配位结构含有6个Ag(I)原子、6个S原子和6个N原子,每个Ag(I)通过2个S原子和1个N原子分别与3个MBI配位,其中Ag(I)原子和S原子皆形成桥键。簇合物核由Ag—S—Ag和S—Ag—S桥键形成2个椅式构型的六元环结构,然后通过Ag…Ag次级作用构成罕见的双层六幅轮毂结构。     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.