共查询到20条相似文献,搜索用时 328 毫秒
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研究了在35±0.1℃、离子强度0.5mol/L(KCl)条件下,甲酸根、乙酸根、丙酸根和丁酸根分别催化Cu(Ⅱ)离子与四溴化间-四(N-乙酸甲酯基-3-吡啶基)卟啉(H2Tβ-N-ACMspyPBr4)的反应动力学及其机理,该类反应对卟啉和Cu(Ⅱ)离子均为一级反应,反应动力学方程为:d[CuP^4+]/dt=k{1.0+b[A^-])/(1.0+K3,4.[H^+]^2}[Cu^2+][P]T 相似文献
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利用同步辐射和超声射流技术产生了团簇离子(CH_3CN)_m(C_2H_3Cl)(m≤4,n≤4)及C2H3ClCN+,C2H2ClCN+由(CH3CN)(C2H3Cl)+经团簇内离子。分子反应生成,反应过程中放出能量使H3C-CN键断裂。abinitio计算表明C2H3ClCN+离子是稳定的。同时测得了它们的电离势. 相似文献
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一种基于形成杂多核络合物的荧光增敏效应的研究:Ⅲ.锰(Ⅱ),钴(… 总被引:3,自引:0,他引:3
本研究了Mn^2+和Co^2+对7-(8-羟基-3,6-二磺基萘偶氮)-8-羟基喹啉-5-磺酸-硼砂反应体系的混合荧光增敏作用。实验条件下,荧光增敏强度满足线性加和关系的范围是:Mn^2+浓度0 ̄2.9×10^-7mol/L;Co^2+浓度0 ̄8.8~10^-7mol/L;总浓度不超过1.0×10^-6mol/L。检出限量为Mn^2+4.5×10^-9mol/L和Co^2+1.4×10^-8mo 相似文献
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丙醇—溴化十六烷基三甲胺—硫酸铵—水体系萃取分离汞(Ⅱ) 总被引:1,自引:0,他引:1
研究了丙醇-溴化十六烷基三甲胺9CTMAB)-(NH4)2SO4-水体系萃取分离泵的行为及与常见离子分离条件。试验表明:调节pH1.0或3.0,能使Hg从Fe^3+,Co^2+,Ni^2+m,Zn^2+,Mn^2+,Cu^2+,Al63+等离子混合液中分离出来。 相似文献
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酸性镀铜体系的交流阻抗研究 总被引:6,自引:0,他引:6
研究了基础溶液(0.3mol/LCuSO4+1.94mol/LH2SO4)以及添加60mg/LCl^-,300mg/LOP-21,30mg/LPEG-6000,10mg/L2-噻唑啉基-二硫丙烷酸钠(代号TDY,自合成添加剂)后体系的阻抗行为,结果表明:1)Cl^-在铜沉积中有增大阴极极化的作用;2)铜离子的放电为分步反应;即Cu^2+→Cu^+;Cu^+→Cu(吸附)→Cu(晶格),在含有Cl^ 相似文献
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用二甲酚橙作柱前衍生试剂,在C18色谱柱上,以乙腈-水(12:88,V/V)作流动相,六次甲基四胺为对离子试剂,反相离子对高效液相色谱-光度法快速分离测定痕量Ni^2+,Zn^2+,Cu^2+配合物和试剂在8min内出峰完毕,575nm处检测,检出限分别为(ng/mL):Ni^2+0.83,Zn^2+0.01,Cu^2+,1.30,用于植物样品中Ni^2+,Zn^2+,Cu^2+的测定,结果令人满 相似文献
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应用量子化学从头计算能量解析梯度法,以HF6/31G为基组优化了HCnS^-与HSC^-n(n=1~9)同分异构团簇离子的几何结构,计算了它们的电子总能量,结果显示HCnS^-比相应的HSC^-n稳定,从相邻簇离子的能量差及簇离子的平均原子结构能可知n为偶数的HCnS^-与HSCn^-较n为奇数的簇离子稳定,能量的差异随着n的增加而逐渐减小,计算和实验结果完全相符,还分别计算了HCnS^-失去H, 相似文献
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Uroš Grošelj Mojca Žorž Amalija Golobič Branko Stanovnik Jurij Svete 《Tetrahedron》2013,69(52):11092-11108
A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives. 相似文献
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The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp3)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp2)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp2)?H and aliphatic 1,5- and 1,6-C(sp3)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp3)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp2)?H insertion. 相似文献
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N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%). 相似文献
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Shashikant U. Dighe Surya K. Samanta Shivalinga Kolle Sanjay Batra 《Tetrahedron》2017,73(17):2455-2467
An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y1 and Y2. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones. 相似文献
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In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates. 相似文献
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An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions. 相似文献
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Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described. 相似文献
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用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在. 相似文献
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An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a–g and imidazo[1,5-a]quinoxalines 7a–h by the reaction of 2-imidazolyl anilines 4a–c with aryl aldehydes 5a–k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a–b was found to be instrumental for the success of the reaction. 相似文献
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The Diels-Alder reactivity of 1,2-heteroborines (H4C4B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed. 相似文献