首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
Gemini表面活性剂因其特殊的分子结构,使它在降低表面张力的效率与效能,以及起泡性、乳化力、润湿性等方面的性能大大优于传统表面活性剂。由此,Gemini表面活性剂成为近年日用化工及胶体与界面化学领域研究的热点课题之一。目前,Gemini表面活性剂优良的表化性能已被广泛认识,相应的理论研究趋于成熟,但Gemini表面活性剂在实际生产中的应用却不多见,究其原因主要是Gemini表面活性剂大都合成路线长,产品价格高,从而限制了它们的使用。本文拟以α-十四烯烃磺酸为原料,采用“一步法”合成萘(苯)双十四烷基双磺酸钠Gemini表面活性剂,其合成路线和反应条件均与现在生产α-烯烃磺酸钠相似,但成本却低于后者,有望实现高的性能价格比。  相似文献   

2.
New square-planar bis(macrocyclic)dicopper(II) complexes containing phenylene bridges between 16-membered pentaaza macrocyclic subunits have been synthesized via in-situ one pot template condensation reaction (IOPTCR) of aromatic nitrogen-nitrogen linker (R = 1,4-phenylenediamine; benzidine; 4,4′-diaminodiphenylmethane; 4,4′-diaminodiphenylether; 4,4′-diaminodiphenylsulfone), formaldehyde, bis(1,3-diaminopropane)copper(II) perchlorate and 1,3-dibromopropane in a 1:4:2:2 molar ratio results in the formation of new series of binuclear copper(II) complexes; 1-phenyl- (1); 1,1′-phenyl- (2); 1,1′-diphenylmethan- (3); 1,1′-diphenylether- (4); 1,1′-diphenylsulfone- (5) bis(1,3,7,11,15-pentaazacyclohexadecane)copper(II)), {[Cu([16]aneN5)]2R}(ClO4)4″. The formation of the macrocyclic framework and the mode of bonding of the complexes have been confirmed by data obtained from elemental analyses, UV-visible, FT-IR, 1H-NMR, electronic spectral studies, conductivity and magnetic susceptibility measurements. These bis(macrocyclic) complexes catalyzed efficiently the selective oxidation of tetrahydrofuran into tetrahydrofuran-2-one and a small amount of tetrahydrofuran-2-ol and 4-hydroxybutyraldehyde using dil. H2O2 as the oxidant.  相似文献   

3.
The synthesis of carbonyl compounds by oxidation of alcohols is a key reaction in organic synthesis. Such oxidations are typically conducted using catalysts featuring toxic metals and hazardous organic solvents. Considering green and sustainable chemistry, a copper(II) complex of sulfonated 2-quinoxalinol salen (sulfosalqu) has been characterized as an efficient catalyst for the selective oxidation of propargylic, benzylic, and allylic alcohols to the corresponding carbonyl compounds in water when in combination with the oxidant tert-butyl hydroperoxide. The reactions proceed under mild conditions (70 °C in water) to produce yields up to 99% with only 1 mol % of catalyst loading. This reaction constitutes of a rare example of propargylic alcohol oxidation in water, and it makes this process greener by eliminating the use of hazardous organic solvents. Excellent selectivity was achieved with this catalytic protocol for the oxidation of propargylic, benzylic, and allylic alcohols over aliphatic alcohols. The alcohol oxidation is thought to go through a radical pathway.  相似文献   

4.
A series of Cu(I) and Cu(II) complexes containing substituted ketiminate ligands was synthesized. Reaction of CuCl2 with 2 equiv. of Li[OC(Me)CHC(Me)N(Ar)] in toluene generated dark green solid of Cu[OC(Me)CHC(Me)N(Ar)]2 (1). Similarly, Cu(I) complex, {Cu[OC(Me)CHC(Me)N(Ar)]Li[OC(Me)CHC(Me)N(Ar)]}2 (2) was synthesized by reacting 2 equiv. of Li[OC(Me)CHC(Me)N(Ar)] with CuCl in toluene at room temperature for 12 h. While the reaction of CuCl with Li[OC(Me)CHC(Me)N(Ar)] in the presence of triphenylphosphine in THF solution at room temperature, a three-coordinated Cu[OC(Me)CHC(Me)N(Ar)](PPh3) (3) can be isolated in high yield. Replacing the PPh3 of 3 with N-heterocarbene (NHC) generates Cu[OC(Me)CHC(Me)N(Ar)](NHC) (4) in low yield. Complexes 2, 3, and 4 were characterized by 1H and 13C NMR spectroscopies and all molecules were structurally characterized by X-ray diffractometry. Two coordination modes of ketiminate ligands were found in the molecular structure of 2, one of which is copper-coordinated terminal ketiminates and the other is lithium-copper-coordinated bridging ketiminates.  相似文献   

5.
1,2-Dioximes undergo oxidative transformation mediated by copper(II) ions in acetonitrile to form the corresponding furoxans in high yields. A series of 1,2-dioximes including aliphatic, aromatic, and heterocyclic dioximes were oxidized using these mild conditions.  相似文献   

6.
Cu(phen)2+2和Cu(bpy)2+2与6-巯基嘌呤、腺嘌呤相互作用的研究   总被引:9,自引:0,他引:9  
在pH为7.0的磷酸盐缓冲溶液中,用荧光光谱、紫外光谱、电化学及紫外光谱电化学等方法研究了铜配合物与6-巯基嘌呤、腺嘌呤的相互作用.结果表明,Cu(phen)2+2和Cu(bpy)2+2与6-巯基嘌呤、腺嘌呤发生了相互作用,但作用程度不同.根据荧光光谱实验数据计算出Cu(phen)2+2和Cu(bpy)2+2与6-巯基嘌呤、腺嘌呤的配位比均为1∶1;它们与6-巯基嘌呤作用的配位常数分别为2.23×104L/mol和6.11×104L/mol;与腺嘌呤作用的配位常数分别为1.95×104L/mol和5.12×104L/mol.电化学实验也获得了相近的结果.这为解释Cu(phen)2+2和Cu(bpy)2+2与DNA的作用机理及作用部位提供了有益的信息  相似文献   

7.
Two new mononuclear copper(II) complexes ([CuL1]·CHCl3 (1) and [CuL2] (2)) have been prepared by the reaction of two ONNO type Schiff base ligands, ([bis(2-hydroxy-propiophenone)2,2′-dimethylpropan-diamine] (H2L1) and [bis(5-bromosalicylaldehyde)2,2′-dimethyl-propandiamine] (H2L2)) with Cu(OAc)2·H2O in 1:1 molar ratios. The complexes have been characterized by elemental analyses, IR and UV-Vis spectroscopy. The structures have been confirmed by X-ray single crystal analysis at 100 K. The Cu(II) atom in 1 is coordinated equatorially by a N2O2 donor set of the tetradentate, dinegative Schiff-base (L1)2− in a distorted square planar arrangement. While in [CuL2] (2), the Cu(II) ion possesses an additional weak intermolecular contact with one bromine atom of the ligand, thus the coordination sphere of 2 can be described as strongly distorted square pyramidal. The catalytic performance of the prepared copper complexes for the oxidation of styrene and cyclooctene with tert-butyl hydroperoxide has been evaluated.  相似文献   

8.
Cu(II) complexes of 14- and 16-membered tetraaza macrocyclic ligands have been encapsulated in nanopores of zeolite-Y by a two-step process in the liquid phase: (1) adsorption of [bis(diamine)copper(II)] (diamine = 1,2-diaminoethane, 1,3-diaminopropane, 1,2-diaminobenzene, and 1,3-diaminobenzene); [Cu(N–N)2]2+–NaY; in the nanopores of the zeolite-Y and (2) in situ condensation of the copper(II) precursor complex with ethylcinnamate. The new host–guest nanocomposite materials were characterized by chemical analysis and spectroscopic methods. The “neat” and encapsulated complexes exhibit good catalytic activity in the oxidation of ethylbenzene at 333 K, using tert-butyl hydroperoxide as the oxidant. Acetophenone was the major product though small amounts of o- and p-hydroxyacetophenones were also formed revealing that C–H bond activation takes place both at benzylic and aromatic ring carbon atoms.  相似文献   

9.
运用M06-2X和ωB97XD方法分别在6-311++G(2d,p)和TZVP基组水平上,对脯氨酸(Pro)的15种构象与Cu、Cu+和Cu2+形成的多种配合物的几何结构、能量学特征、振动光谱和电子结构等进行计算研究.四种水平得到20种[Pro-Cu]、16种[Pro-Cu]+和16种[Pro-Cu]2+稳定结构.[Pro-Cu]和[Pro-Cu]+体系中出现12种Pro构象,而[Pro-Cu]2+体系中出现11种Pro构象,三种体系中最稳定的结构都不是由能量最低的Pro构象生成的.在结构CI3、CI4、CII7和CII8中,Pro的羧基氢转移到亚氨基氮形成两性离子与Cu双配位结合.[Pro-Cu]0/1+/2+体系四种水平计算相对能差范围逐渐增加,结合能分别在-60.0--5.0 kJ·mol-1、-340.0--170.0 kJ·mol-1和-1100.0--860.0 kJ·mol-1范围,配位体系中Pro的变形能逐渐增加.N―H和O―H键伸缩振动频率普遍发生红移,配位体系中部分电荷从Pro转移到Cu上,在[Pro-Cu]2+体系中单配位结构中电荷转移最多,约为单位负电荷.  相似文献   

10.
The new dipyridyl ligands N,N′-(methylenedi-p-phenylene)bis(pyridine-4-carboxamide), L1, and N,N′-(methylenedi-p-phenylene)bis(pyridine-3-carboxamide), L2, incorporating amide spacers have been synthesized and reacted with metal salts to give complexes of the types [Cu(L1)2X2] (X = Cl, 1 and X = Br, 2), {[Cu(L1)2(DMF)](NO3)2}, 3, {[Ag2(L1)2](SO4)}, 4, and {[Cu(L2)(DMSO)2(NO3)](NO3)}, 5. All compounds have been characterized by spectroscopic methods and their structures determined by X-ray crystallography.Complexes 1, 2 and 3 form 1-D double-stranded polymeric chains showing rhombic molecular squares with approximate dimensions of 16.95 × 19.13 Å2 for 1, 17.03 × 19.06 Å2 for 2 and 16.66 × 19.94 Å2 for 3. Complex 4 forms infinite 1-D zigzag polymeric chains, which are interlinked through a series of Ag–O interactions to form wavy 1-D ladder like chains, and complex 5 forms 1-D sinusoidal chains. While the L1 ligands in complexes 1, 2 and 3 adopt the cis conformation and that in complex 4 adopts trans conformation, the L2 ligand in complex 5 adopts the trans-anti conformation. The ligand conformations also differ in the dihedral angles between the pyridyl and phenyl rings. All complexes exhibit emissions which may be tentatively assigned as intraligand (IL) π → π* transition.  相似文献   

11.
A mild copper(II)-catalyzed oxidation of 4-carboxythiazolines and 4-carboxyoxazolines to 4-carboxythiazoles and 4-carboxyoxazoles has been developed. Various substrates with alkyl or aryl substitutions at 2-position on azoline ring could be smoothly oxidized to the desired products in good to excellent yields. Moreover, the hydrolysis of the ester group could be avoided under this method.  相似文献   

12.
A copper-catalyzed oxidative esterification of 2-carbonyl substituted phenols from the alcohol oxidation level is described. This protocol represents direct access to a range of 2-carbonylated aryl benzoate derivatives, which are important building blocks in the synthesis of natural and pharmacological compounds.  相似文献   

13.
The rates of oxidation of Cu(I) in air saturated solutions was measured as a function of pH, temperature (5–45°C), and ionic strength (0.5 to 6m) in NaCl and NaCl–NaClO4 solutions. In pure NaCl solutions, the effect of pH is independent of ionic strength and temperature. The overall rate constant is given by logk=12.32+0.12(pH)–2064/T–3.69I1/2+ 0.73I The energy of activitation was 39±2 kJ-mol–1 and is independent of ionic strength. At a constant ionic strength (I=1, 3 and 6m) in NaCl–NaClO4 mixtures the Cl dependence of the rates is attributed to the oxidation of the various forms of Cu(I) in the solution. The rate constants for the oxidation of the various species are found to be functions of ionic strength. At a constant ionic strength (I=1) in NaCl–NaClO4 solutions, the effect of temperature is independent of the chloride concentration. The effect of Mg2+ and HCO 3 on the oxidation rate was determined as a function of chloride concentration (1 to 6m) at 25°C and pH=8. The addition of Mg2+ causes the rate to decrease and the addition of HCO 3 causes the rate to increase. The possible causes of these effects are discussed. Empirical equations for the rate of oxidation of Cu(I) in Na-Mg-Cl-HCO3 solutions as a function of composition are used to make reliable estimates of the oxidation in seawater and Red Sea waters.  相似文献   

14.
It has been established that during the separation of Cu(I)-cyanide complexes, the cyanide:Cu(I) molar ratio, R of the eluted complex remained constant irrespective of the R value injected onto the column, and there was considerable tailing of the unretained cyanide peak and fronting of the Cu(I)-cyanide peak in an eluent containing no cyanide. The addition of small amounts of cyanide (100 μM) to the eluent resulted in the elimination of these effects on peak shape and a significant increase in the retention of the Cu(I)-cyanide species. These results suggested that more than one Cu(I)-cyanide complex may be present in the Cu(I)-cyanide peak in an eluent containing no cyanide. Three different detection systems [Fourier transform Infrared (FTIR) and photodiode array spectrophotometry and a post-column reaction (PCR)], were used to determine changes that occurred to the Cu(I)-cyanide complexes during the separation with eluents containing from 0 to 100 μM cyanide. The FTIR approach was unsuccessful due to a lack of sensitivity. The UV spectrum of the Cu(I) peak in any one eluent remained constant, irrespective of the composition of the injected sample, but there were distinct changes in this spectrum among eluents. Similarly, the R value of the Cu(I) peak determined by PCR remained the same in any one eluent but ranged from about 2.5 to about 3.4 for these eluents. The R value was found to vary within the eluted Cu(I)-cyanide peak, especially in an eluent containing no added cyanide. These results show that more than one Cu(I)-cyanide complex is present in the eluted peak and that in the absence of cyanide in the eluent, the eluted peak consists of a mixture of the di- and tricyano complexes of Cu(I).  相似文献   

15.
N,N′-Bis(salicylidene)cyclohexane-1,2-diamine (H2sal-dach) reacts with oxovanadium(IV) and copper(II) exchanged zeolite-Y in refluxing methanol to yield the corresponding zeolite-Y encapsulated metal complexes, abbreviated herein as [VO(sal-dach)]-Y and [Cu(sal-dach)]-Y. Spectroscopic studies (IR, electronic and 1H NMR), thermal analysis, scanning electron micrographs (SEM) and X-ray diffraction patterns have been used to characterise these complexes. These encapsulated complexes catalyse the oxidation, by H2O2, of styrene, cyclohexene and cyclohexane efficiently in good yield. Under the optimized conditions, the oxidation of styrene catalysed by [VO(sal-dach)]-Y and [Cu(sal-dach)]-Y gave 94.6 and 21.7% conversion, respectively, where styreneoxide, benzaldehyde, benzoic acid, 1-phenylethane-1,2-diol and phenylacetaldehyde being the major products. Oxidation of cyclohexene catalysed by these complexes gave cyclohexeneoxide, 2-cyclohexene-1-ol, cyclohexane-1,2-diol and 2-cyclohexene-1-one as major products. Conversion of cyclohexene achieved was 86.6% with [VO(sal-dach)]-Y and 18.1% with [Cu(sal-dach)]-Y. A maximum of 78.1% conversion of cyclohexane catalysed by [Cu(sal-dach)]-Y and only 21.0% conversion by [VO(sal-dach)]-Y with major reaction products of cyclohexanone, cyclohexanol and cyclohexane-1,2-diol have been obtained.  相似文献   

16.
Rima Das 《Tetrahedron letters》2010,51(48):6255-6258
A variety of sulfides and disulfides were converted into the corresponding sulfoxide derivatives with 70% t-BuOOH (water) as the oxidant in the presence of catalytic quantity of CuBr2. The method described does not involve cumbersome work-up, has wide range of applicabilities, exhibits chemoselectivity, and proceeds under mild reaction conditions, and the resulting products are obtained in good yields within reasonable time.  相似文献   

17.
An NMR method is described and applied, which allows the investigation of the first coordination sphere of certain transition metal ions. It is based on the measurement of the solvent proton nuclear magnetic relaxation times both as a function of magnetic field and of concentration of an admixed diamagnetic salt. This procedure enables an unambiguous separation of dynamic effects from ion-pair formation effects, which both can influence the relaxation times. As an application of this method, the complex formation of Mn2+ and Cu2+ with Br, I, ClO 4 , and SO 4 2– in aqueous solution is studied. Thus the hydration numbersn H2O of these cations as a function of anion concentration are obtained, allowing the detection of weak inner-sphere or outersphere complexes. Also several complex stability constants are derived and are compared with literature data.  相似文献   

18.
Four copper(II) coordination polymers, {[Cu(pz(COO)2)(H2O)]4·HBr}n (1), {[Cu(pz(COO)2)(NH3)2]·H2O}n (2), {[Cu3H2(pz(COO)2)4(H2O)3]·2H2O}n (3) and {[Cu2(pz(COO)2)2(NH3)2(H2O)3][Cu(pz(COO)2)(NH3)(H2O)2][Cu(pz(COO)2)(NH3)(H2O)]·2H2O}n (4) were synthesized using pyrazine-2,3-dicarboxylic acid, CuBr2, 2-(2-aminoethylamino)ethanol/triethanol amine/ammonia in a methanol:water (1:1) solution, and the mixed ligand complexes were characterized by spectroscopic methods, thermal and elemental analysis, and magnetic susceptibility. Complexes 2 and 4 were also characterized by means of single crystal X-ray crystallography. The characterizations show that the complexes have polynuclear molecular structures, except for complex 2, and all of the complex structures form polymeric chains. Complex 4 has a pseudo-merohedral twin structure.  相似文献   

19.
Electronic spectra for a series of coordination compounds of copper(II) with tridentant ligands of salicyl aldehyde S-methylthiosemicarbazone and 8-quinoline aldehyde S-methylthiosemicarbazone were investigated. Coordinations of central ions were determined on the basis of X-ray data and IR spectra. Electronic transitions were detected by processing the diffusion-reflection spectra according to theKubelka-Munk theory. Identifications proved the presence of bands corresponding to intraligand transition, charge transfer spectra and the transition of d-d type which are the result of the elimination of d-orbital degeneration for Cu(II) ions in the crystal field. The effect of the symmetry of coordination polyhedrons is discussed.
Elektronenspektren von Cu(II) Kristall-Komplexen mit S-Methylthiosemicarbazonen
Zusammenfassung Es wurden Elektronenspektren einer Serie von Koordinationsverbindungen des Kupfer(II) mit tridentaten Liganden (Salizylaldehyd-S-methylthiosemicarbazon und 8-Chinolinylaldehyd-S-methylthiosemicarbazon) untersucht. Die Zentralionkoordination wurde durch Röntgenstrahlenuntersuchungen und auf Grund der IR-Spektren festgestellt. Die Elektronenübergänge wurden nach derKubelka-Munk-Theorie aus den diffusen Reflexionsspektren ermittelt. Die Banden wurden den Intraligandübergängen, dem charge-transfer-Spektrum und den d-d-Typ-Übergängen, die als Resultat der Entartungsbeseitigung der Cu(II)-d-Orbitale im Kristallfeld verschiedener Symmetrie entstehen, zugeschrieben.
  相似文献   

20.
The relation between the structure of Cu2+ complexes and their catalytic activity in the decomposition of H2O2 can be used as a “molecular probe”, since it allows the deduction of the number of coordinated ligand groups in a Cu2+ complex from its catalytic activity. Since only coordinated ligand groups are oxidized by H2O2, further information about the coordination sphere of the metal ion can be obtained from the oxidation of certain parts of a ligand, which can be followed spectrophotometrically. The Cu2+ complexes of amides, polyamino acids, nucleotides, RNA, and native and denatured DNA have been investigated in this way. Kinetic studies provide an insight into the mechanisms of catalase and peroxidase reactions.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号