镍钨磷合金电结晶机理及其镀层结构与显微硬度

应用循环伏安、恒电位阶跃和 X射线衍射（ XRD）等方法研究了 Ni-W-P合金电沉积特点和镀层结构与显微硬度 .结果表明,在以柠檬酸铵为配体的溶液中, Ni-W-P合金沉积层较 Ni-W合金有较低的电化学活性 .根据电位阶跃的 i～ t曲线分析表明,在玻碳电极上 Ni-W-P合金电结晶过程遵从扩散控制瞬时成核三维成长模式进行,随着过电位的增加,电极表面上晶核数增多 . XRD试验结果表明, Ni-W-P合金镀层呈现明显的非晶态特征 .所获得的 Ni-W-P合金电沉积层的显微硬度在 450 kg· mm－ 2左右 .     

镍钨硼合金沉积机理及镀层微晶尺寸

应用循环伏安、恒电位阶跃和Ｘ射线衍射（ＸＲＤ）等研究了Ｎｉ－Ｗ－Ｂ合金电沉积特点和镀层微晶尺寸。结果表明,在以柠檬酸铵为络合剂的溶液中,Ｎｉ－Ｗ－Ｂ合金沉积层较Ｎｉ－Ｗ合金有较低的电化学活性。电位阶跃ｉ￣ｔ曲线分析表明,在玻碳电极上Ｎｉ－Ｗ－Ｂ合金电结晶过程遵循扩散控制瞬时成核三维成长模式,且随过电位的增加,电极表面晶核数增多。ＸＲＤ测试结果表明,随沉积电流密度提高,合金镀层微晶尺寸逐渐增大,说明     

玻碳电极表面因瓦合金的电化学成核机理

在弱酸性因瓦合金(含镍质量分数为32~36 % 的镍铁合金)镀液中, 以线性扫描伏安法、循环伏安法和恒电位阶跃法对因瓦合金在玻碳电极表面的电沉积过程及其成核机理进行研究. 结果表明, 在该体系下, 因瓦合金在玻碳电极表面的电结晶属于扩散控制下的不可逆电极过程. 运用Scharifker-Hills理论模型(SH)拟合实验数据表明, 因瓦合金在玻碳电极表面的共沉积更加符合三维瞬时成核的成核规律. 运用Heerman-Tarallo理论模型(HT)分析得到因瓦合金在玻碳电极表面的成核生长的动力学参数, 当阶跃电位从-1.11 V变化至-1.17 V (vs SCE), 成核密度数(N₀)由0.72×10⁵ cm^-2提高至1.91×10⁵ cm^-2, 成核速率常数(A)从 40.35 s^-1增至 194.38 s^-1, 扩散系数(D)为(7.67±0.15)×10^-5 cm²•s^-1, 变化不大.     

Au/PAni/GC电极的制备及对甲醛的电催化氧化研究

应用循环伏安、恒电位阶跃等方法研究了在苯胺修饰的玻碳电极（PAni/GC） 表面金颗粒的电化学沉积及不同的制备方法对甲醛氧化电催化活性的影响。研究表 明,在PAni/GC电极表面,金的电沉积在初始阶段遵循扩散控制瞬时成核三维成长 模式。在碱性介质中,电解沉积法制备的电极比循环伏安法制备的电极对甲醛的催 化氧化有更高的催化电流。但是,在循环伏安法制备的电极上甲醛的氧化可以在很 负的电极电位下发生。     

镍钨磷合金电结晶机理及其镀层结构与显微硬度

应用循环伏安,恒电位阶跃和Ｘ射线衍射（ＸＲＤ）等方法了Ｎｉ－Ｗ－Ｐ合金电沉积特点和镀层结构与显微硬度,结果表明,在以柠檬酸铵为配体的溶液中,Ｎｉ－Ｗ－Ｐ合金 层较Ｎｉ－Ｗ合金有较低的电化学活性,根据电位阶跃的ｉ－ｔ曲线分析表明,在玻碳电极上Ｎｉ－Ｗ－Ｐ合金电结晶过程遵从扩散控制瞬时成核三维成长模式进行,随着过电位的增加,电极表面上晶核数增多,ＸＲＤ试验结果表明,Ｎｉ－Ｗ－Ｐ合金镀层呈现明显的非晶态特征,所获得的Ｎｉ－Ｗ－Ｐ合金电沉层的显微硬度在４５０ｋｇ．ｍｍ＾－２左右。     

镍钨硼合金电沉积机理及镀层微晶尺寸

应用循环伏安、恒电位阶跃和X射线衍射 (XRD)等方法研究了Ni_W_B合金电沉积特点和镀层微晶尺寸 .结果表明 ,在以柠檬酸铵为络合剂的溶液中 ,Ni_W_B合金沉积层较Ni_W合金有较低的电化学活性 .电位阶跃i～t曲线分析表明 ,在玻碳电极上Ni_W_B合金电结晶过程遵循扩散控制瞬时成核三维成长模式 ,且随过电位的增加 ,电极表面晶核数增多 .XRD测试结果表明 ,随沉积电流密度提高 ,合金镀层微晶尺寸逐渐增大 ,说明电流密度提高将更加有利于Ni_W_B合金电结晶过程中的晶核生长 .     

玻碳电极表面复合配位银电结晶机理研究

以具有实际应用价值的复合配位体系无氰镀银电解液为研究对象, 运用循环伏安和电位阶跃等实验方法, 结合 Scharifker-Hill 经典理论模型分析, 成功获得了Ag在玻碳电极（GCE）表面电沉积的成核机理及成核动力学参数, 并分析了温度对成核方式及成核动力学参数的影响. 结果表明, 该体系下Ag在GCE表面的电沉积是由扩散控制的不可逆过程, 遵循三维瞬时成核生长机理. 随着阶跃电位从-750 mV 负移至-825 mV, 峰值还原电流Im逐渐增大, 达到峰值还原电流所需时间tm逐渐缩短; 扩散系数D变化不大, 基本稳定在（7.61±0.34）×10^-5 cm²·s^-1; 成核密度数N₀则从3.26 ×10⁵ cm^-2提高至10.2×10⁵ cm^-2. 银沉积初期的形貌观察, 验证了其三维瞬时成核生长机理. 提高温度可以显著改善电解液中具备活性的银配位离子的扩散能力, 缩短成核时间, 提升成核密度数N0.     

ITO导电玻璃表面直接电沉积Au的机理

用循环伏安和电位阶跃法研究Au在氧化铟锡(ITO)透明导电膜玻璃表面的电沉积过程的初期阶段. 发现在ITO表面Au的电沉积经历成核过程以及受[AuCl₄]^-扩散控制的晶核生长过程. 通过改变扫描速率分析循环伏安曲线的变化, 当扫描速率较快时, 发现Au在ITO表面的沉积过程经历[AuCl₄]^-→[AuCl₂]^-→Au两步进行; 当扫描速率较慢时, 受歧化反应作用影响而只表现为一步沉积[AuCl₄]^-→Au. 通过电位阶跃实验, 验证了Au的两步沉积过程, 并求得[AuCl₄]^-的扩散系数为1.3×10^-5 cm²·s^-1. 将成核曲线与理论曲线对照, 得出Au在ITO表面的沉积符合瞬时成核理论. 通过场发射扫描电镜(FE-SEM)对Au核形貌进行分析, 根据扫描电镜图可以得到阶跃时间和阶跃电位对电沉积Au的形貌的影响.     

添加剂丙烯基硫脲对镍电沉积的影响研究

采用循环伏安、线性扫描和恒电位阶跃电化学方法结合扫描电镜研究了不同浓度的丙烯基硫脲(ATU)对NH₃-NH₄Cl-H₂O体系镍在玻碳电极上的电沉积过程的影响. 循环伏安测试、线性扫描以及恒电位暂态曲线一致表明ATU的加入对镍电沉积具有阻化作用,并且随着ATU浓度的增加其阻化作用增强;恒电位暂态曲线结果表明,镍的电结晶是按瞬时形核三维生长机理进行的,随外加电位负移,晶体向外生长速率增大;ATU的加入没有改变镍的形核方式,但形核数密度增大,并且减小晶体向外生长的速率;扫描电镜结果表明,ATU的加入可以细化晶粒,得到整平、致密的镍沉积层.     

添加剂作用下钯电沉积行为研究

在含有4 g•L－1 Pd(NH3)2Cl2和104 g•L－1 NH4H2PO4的闪镀钯基础电解液中,采用极化曲线、循环伏安法和计时安培法研究添加剂作用下钯在玻璃碳电极上的电沉积和电结晶行为.结果表明,添加剂阻化钯的电沉积;钯在玻碳电极上的交换电流密度很低;钯电沉积过程经历了晶核形成过程,其电结晶机理在不含添加剂时接近于三维连续成核,含添加剂时接近于三维瞬时成核.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

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.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

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.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

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%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

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.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

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.     

Synthesis of pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles by Curtius reaction in Morita-Baylis-Hillman derivatives

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.     

正丁胺对激光染料荧光谱影响的研究

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.     

Cu0-catalysed 1,3-dipolar cycloadditions of α-amino acid derived N,N-cyclic azomethine imines to ynones

A series of 20 CuAIAC reactions between eight 4-acylamino substituted pyrazolidine-3-one-1-azomethine imines and four terminal ynones were performed using Cu⁰ as catalyst. The corresponding fluorescent cycloadducts were obtained in very high yields upon simple workup. Thus, Cu-metal turned out to be a better catalyst than Cu^I in terms of yield and ease of isolation. Availability of azomethine imines, mild reaction conditions, and simple workup enable a “click” access to libraries of densely substituted 2,3-dihydro-1H,5H-pyrazolo[1,2-a]pyrazol-1-ones. Reactivity of differently substituted dipoles was evaluated experimentally and by quantum chemical methods (DFT).     

Synthesis and antioxidative/anti-inflammatory activity of novel fullerene–polyamine conjugates

(E)-4-(Fullerenopyrrolidin-1-yl)-3-methylbut-2-enoic acid and its corresponding succinimidyl ester, readily obtained through Prato-type modification of C₆₀, were used for the selective N-acylation of polyamines. The thus obtained conjugates were evaluated for their antioxidative and anti-inflammatory activity and their cytotoxicity was determined. Members of this family of compounds showed interesting anti-lipid peroxidation, anti-lipoxygenase and anti-inflammatory activity and comparable cytocompatibility to spermidine.