基态和亚稳态的Ca、Ba原子与CIO_2化学发光反应的动态学研究

在束-气装置上的单次碰撞条件下,利用低压直流放电选择性地激发碱土金属到亚稳态,观察了Ca(~1S)、Ca(~1S’~3P)、Ba(~1S)、Ba(~1S,~3D)+ClO_2。反应的化学发光.通过测量化学发光总包光强的空间分布,得到这些反应的总碰撞截面为:Ca(~1S)+ClO_2,97(A~2);Ca(~3P)+ClO_2,138(A~2);Ba(~1S)+ClO_2,136(A);Ba(~3D)+ClO_2,239(A~2),计算机模拟化学发光光谱,发现新生产物MO(M=Ca,Ba)的电子激发态A~1П态的相对振动布居分布是非玻尔兹曼分布的,求出反应Ba(~3D)+ClO_2和Ca(~3P)+ClO_2产生的MClC~П→X~2 ∑~+跃迁的化学发光截面分别为51(A~2)和31(A~2),计算光谱中不同成份的光强,得到了反应产生MO、MCl的产物分支比.最后,讨论了这类反应的机理。     

基态和亚稳态的Ca、Ba原子与ClO2化学发光反应的动态学研究

在束-气装置上的单次碰撞条件下, 利用低压直流放电选择性地激发碱土金属到亚稳态, 观察了Ca(~1S)、Ca(~1S’~3P)、Ba(~1S)、Ba(~1S, ~3D)+ClO_2。反应的化学发光. 通过测量化学发光总包光强的空间分布, 得到这些反应的总碰撞截面为: Ca(~1S)+ClO_2, 0.97 nm; Ca(~3P)+ClO_2, 1.38 nm; Ba(~1S)+ClO_2, 13.6 nm; Ba(~3D)+ClO_2, 2.39 nm, 计算机模拟化学发光光谱, 发现新生产物MO(M=Ca, Ba)的电子激发态A~1П态的相对振动布居分布是非玻尔兹曼分布的, 求出反应Ba(~3D)+ClO_2和Ca(~3P)+ClO_2产生的MClC~П→X~2 ∑~+跃迁的化学发光截面分别为0.51 nm和0.31 nm, 计算光谱中不同成份的光强, 得到了反应产生MO、MCl的产物分支比. 最后, 讨论了这类反应的机理。     

含呋喃环系西佛碱型大环化合物的合成

利用 Mn~(++)和 Ba~(++)作为模板离子,合成了一类新型的含呋喃环系西佛碱型大环化合物L~1 和配合物 L~2 Ba(ClO_4)_2、L~3 Ba(ClO_4)_2 和 L~4 Ba(ClO_4)_2.L~2～L~4 的 Ba~(++)配合物经与 Na_2 SO_4 水溶液反应解络,得到自由配体 L~2、L~3 和 L~4。配体 L~2 和 L~3 分别与 Sr~(++)作用,得到配合物 L~2 Sr(ClO_4)_2 和 L~3 Sr(ClO_4)_2。上述大环配体和各种配合物均经元素分析、IR、~1HNMR、MS 等证实了它们的结构和组成。     

三元体系LaX3—PIAP—H2O（X^—=ClO4^—,NO3^—,Cl^—）（30℃）的相平衡

测定了三个三元体系LaX_3-PIAP-H_2O（X~- = ClO_4~-，NO_3~-，Cl~-， PIAP为4－（邻苯二甲酰基）亚基安替比林）在30℃时的溶解度。研究发现La (NO_3)_3-PIAP-H_2O和LaCl_3-PIAP-H_2O体系均为简单共饱型；La(ClO_4)_3- PIAP-H_2O体系有一个新固相形成，其组成为La(PIAP)_3（ClO_4）_3·4H_2O和体 系均为简单共饱型；La(ClO_4)_3-PIAP-H_2O体系的相平衡研究结果，合成了相应 的镧系配合物Ln(PIAP)_3(ClO_4)_3·4H_2O(Ln = La, Pr, Nd, Sm, Gd, Yb)，通 过化学分析、元素分析TG-DTG'IR谱和密度对化合物进行了表征。     

中性磷(膦)类稀土萃合物的结构研究(Ⅳ)——四(三苯基氧膦)高氯酸钕合二丙酮的合成和结构

合成了四(三苯基氧膦)高氯酸稀土络合物。有关鉴定和元素分析表明,络合物的分子式为Ln(ClO_4)_3·4PhPO,其中Ln=La、Pr、Nd、Sm、Eu。用X射线单晶衍射法测定了CNd(ClO_4)_2·4Ph_3PO]ClO_4·2CH_3COCH_3的晶体和分子结构,该晶体属单斜晶系、P2_(1/c)空间群:a=13.469(5)、b=19.540(8)、c=28.437(9)、β=90.79(3)°、V=7483(5)(?)~3,Z=4。钕与八个氧配位,其中四个氧来自四个三苯基氧膦的膦酰基,四个氧由两个双齿配位的高氯酸根提供,组成了[Nd(ClO_4)_24Ph_3PO]~+络阳离子,它与外界的另一个ClO_4~-以静电相互作用形成分子。溶剂分子CH_3COCH_3不与钕成键。钕的配位多面体具有D_(2d)P_(2m)对称性,是一个不规则的三角十二面体。     

三元体系Ln(ClO4)3-4-ClCH2COAp-H2O(30℃)的相平衡研究(Ln=La,Sm,Er)

我们测定了三元体系 Ln(ClO_4)_3—4-ClCH_2COA_p—H_2O(Ln=La,Sm,Er)存30℃时的溶度及饱和溶液的折光指数,绘制了相应的溶度图和饱和溶液的折光指数曲线图.体系的溶度曲线和折光指数曲线均由四支组成,分别与4-ClCH_2COA_p、Ln(4-ClCH_2COAp)_3(ClO_4)_3·nH_2O(Ln=La,n=7;Sm,8;Er,4)、Ln(4-ClCH_2COAp)_2(ClO_4)_3·nH_2O(Ln=La,n=7;Sm,6;Er,4)和 Ln(ClO_4)_3·nH_2O(Ln=La,n=8;Sm,9;Er,6)相对应,两类配合物均为固液异组成化合物.     

三苯基氧膦钕盐配合物的振动光谱

本文测定了Ph_3PO、Nd(NCS)_3·4Ph_3PO、[Nd(ClO_4)_2·4Ph_3PO]~+ClO_4~-·2CH_3COCH_3以及Nd(NO_3)_3·2Ph_3PO·C_2H_5OH在4000～100 cm~(-1)区域内的FT-IR和激光Raman光谱,分析和讨论了各主要谱带的性质和配位结构.     

喹啉氧基乙酰胺的Li(Ⅰ)/Na(Ⅰ)配合物及其高氯酸盐的结构和荧光性质（英文）

合成并通过X射线单晶衍射表征了配合物[Li(L)_2]ClO_4(1)和[Na(L)_2]ClO_4(2)的结构(L为2-(5-氯-喹啉-8-基氧基)1-吡咯烷酮)。单晶衍射结果表明,配合物1与2同构,金属离子与来自2个酰胺配体L的N_2O_4电子供体配位,形成扭曲的八面体配位构型。此外,还测定了配体高氯酸盐(HL)ClO_4·H_2O的结构,并详细研究了3个化合物的荧光性质。     

高氯酸镧甘氨酸水体系及其新相中配合物La(Gly)_3(ClO_4)_3·2H_2O结构的研究

测定了La(ClO_4)_3-Gly-H_2O在25℃时体系的溶度,并绘制了相应的溶度图.体系中形成了2个新配合物La(Gly)_3(ClO_4)_(3)·2H_2O(Ⅰ)和La(Gly)_4(ClO_4)_3(Ⅱ).(Ⅰ)为固液异成分溶解、(Ⅱ)为固液同成分溶解的化合物,同时以相图为依据合成并培养了配合物(Ⅰ)的单晶,测定了晶体结构,其化学式为(La_2(Gly)_6(H_2O)_4]·6ClO_4,晶体属三斜晶系,P1空间群,每个晶胞中有2个化学式量.晶胞参数:a=1.0693(3)nm,b=1.2956(3)nm,c=0.8762(3)nm,α=82.83(3)°,β=67.25(3)°,γ=71.50(2)°,配位单元中镧为9配位,其配位多面体为畸变的三冠三角棱柱体.     

La(ClO_4)_3-C_(11)H_(12)ON_2-H_2O三元体系相平衡及La(C_(11)H_(12)2ON_2)_6(ClO_4)_3的合成

采用溶解度等温法研究了La(ClO_4)3-C_(11)H_(12)2ON_2(安替吡啉)-H_2O三元体系在0℃时的相平衡,并由此合成了La(C_(11)H_(12)ON_2)_6(ClO_4)_3配合物。还确定了该配合物的制备条件,测定了它的一些性质,并对其结构作了初步分析。     

用旋转园盘-园环电极研究碘酸盐阴极还原反应的机理

本文研究了低浓度的碘酸盐在硫酸介质中, 在铂电报上的电化学还原。用旋转盘环电极检测到了碘酸盐阴极还原的中间产物I_2及最终产物I~-。测定了电化学反应的动力学参数。最后提出了磺酸盐阴极反应的机理。     

Influence of temperature on the reduction kinetics of Bi(III) ion in the presence of cystine in chlorate (VII) solutions of decreased water activity

The results of the kinetic measurements of Bi(III) electroreduction on a mercury electrode in 1–8 mol dm^?3 chlorate (VII) solutions and in the presence of cystine demonstrate a dependence of the process on the temperature. The applied electrochemical techniques (DC polarography, cyclic and SWV voltammetry) allowed for the determination of the kinetic and thermodynamic parameters and their correlation with water activity. The catalytic activity of cystine was confirmed by the decrease in overall enthalpies of activation. The changes in the values of ΔH ^≠ and ΔS ⁰ for Bi(III) electroreduction in the presence of cystine with the increase of chlorate (VII) concentration showed that the mechanism is different in solutions with low water activity as compared to those with high water activity. Probably it is connected with a different structure of the activated complexes (Bi-Hg(SR)₂), mediating electron transfer.      

A chlorate ion-selective electrode based on a poly(vinyl chloride)-matrix membrane

An electrode has been prepared, consisting of a PVC membrane containing Corning 477316 nitrate liquid ion-exchanger in the chlorate form, which responds to chlorate ions. It has a faster response (1-2 sec) and lower limit of detection (3 x 10(-5)M) than the nitrate electrode for chlorate determination. Selectivity coefficients for the electrode towards several other ions have been measured.     

C60电化学还原的稳态性质研究

自1990年9月Kratschmer等报导了C_(60)的常量制备和提纯以来,有关C_(60)及其他富勒炭分子(Fullerens)的研究报导与日俱增,成为近三年来最为活跃的研究领域之一.由于C_(60)的特殊结构,在电化学行为上也表现出十分独特的反应性质,如容易实现多电子氧化还原反应,可逆加氢及能形成离子嵌入电极材料等.本工作采用微电极方法研究了C_(60)稳态极化行为,测定了C_(60)的扩散系数和反应电子数,并通过现场紫外可见光谱电化学方     

The mechanism of electroreduction of nitrate ions on a hybrid electrode nanodispersed copper-MK-40 membrane

Based on a MK-40 sulfocation-exchange membrane, a hybride electrode material containing nanodispersed copper is prepared. The methods of scanning electron microscopy and X-ray diffraction (XRD) analysis reveal the formation of copper agglomerates measuring 250–470 nm and consisting of individual particles of 20–30 nm. The procedure of multistage chemical deposition of copper into the ion-exchange carrier makes it possible to obtain a continuous cluster of metal particles which determines the electron conducting properties of the resulting hybrid material. The electrochemical activity of the nanocomposite electrode is studied in the reaction of nitrate ion electroreduction. Nanodispersed copper deposited into the membrane is shown to intensify the electroreduction of nitrate ions by a factor of 1.5–2 as compared with a compact copper electrode. The electroreduction of nitrate ions on compact copper is shown to involve 6 electrons, whereas the electroreduction on the nanocomposite involves 8 electrons. The electroreduction products of nitrate ions are identified by the IR spectroscopy method.     

乙腈中β-萘磺酸在汞电极上的电还原机理

用循环伏安法、电化学-ESR现场谱学技术和自洽场分子轨道法(CNDO/2)研究了乙腈中β-萘磺酸在汞电极上的电还原机理。结果表明该反应属ECE模式, 电还原服从直接脱磺酸基团机理, 并有萘自由基中间产物的形成。用分子轨道理论对电还原过程作了解释。     

草酸电还原反应机理的研究

以硫酸钠溶液作底液,用快速循环伏安和电势阶跃法研究了草酸在铅电极上的电还原机理,测定了草酸电还原第一步反应的动力学参数,并根据循环伏安图比较相同条件下草酸,乙醛酸和乙醇酸的还原峰峰电势,推断出草酸还原的中间产物.研究结果表明,草酸电还原遵从不可逆2电子EE反应机理.     

Accelerating Effect of Tetramethylthiourea on the Kinetics of Zn2+ Electroreduction

The results of kinetic measurements of Zn²⁺ electroreduction on mercury electrode in the presence of tetramethylthiourea showed the two‐step character of the electrode process. The acquisition of nonlinear wide potential range Tafel plots was found to offer a good opportunity to examine the Zn²⁺ electroreduction mechanism. Three mechanisms including the ion transfer step followed by the electron exchange step (IE mechanism), the adsorption step (IA mechanism) and the chemical step followed by electron transfer (CE) were applied. The accelerating influence of tetramethylthiourea on Zn²⁺ electroreduction was found to result from possible complexes formation in the diffuse layer. The ion transport step is probably combined with the loss or exchange of a ligand. The second step probably consists in the electron transfer or adsorption process connected with partial charge transfer.     

The importance of surface morphology in controlling the selectivity of polycrystalline copper for CO2 electroreduction

This communication examines the effect of the surface morphology of polycrystalline copper on electroreduction of CO(2). We find that a copper nanoparticle covered electrode shows better selectivity towards hydrocarbons compared with the two other studied surfaces, an electropolished copper electrode and an argon sputtered copper electrode. Density functional theory calculations provide insight into the surface morphology effect.     

Black Phosphorene Modified Electrochemical Sensor for Fast Determination of 5-Hydroxymethyl-2-furfural in Milk

The fast detection of 5-hydroxymethyl-2-furfural (HMF) in food industry is vital because of its toxicity and mutagenicity. A glassy carbon electrode (GCE) modified with black phosphorene (BP) nanosheets was prepared and coated with Nafion to improve stability. The electrode has excellent electrochemical stability and current response for HMF electroreduction. The good linear relationship is in the concentration range of 0.1–10 μg/mL with the detection limit of 0.012 μg/mL. HMF electroreduction is a diffusion-controlled process involving two electrons and two protons. The sensor was successfully applied to the measurement of HMF in milk with the recovery values of 92.92 %–96.33 %.