225 resultados para 02202100 Live_tow-12
Resumo:
以环戊二烯与 1 2 钼硅杂多四丁基铵为原料 ,采用光化学法合成了一种新型电荷转移盐 (Bu4N) 4(C5 H6 ) [HSiMoVI11MoVO40 ]。用元素分析、IR、CV、固体漫反射电子光谱、ESR进行了表征。X 射线晶体结构测定其晶体属三斜晶系 ,空间群P1 ,晶胞参数a =1 4.347(3) ,b =1 4.42 3(3) ,c =2 7.1 5 8(5 ) ,α =96 .90 (3) ,β =1 0 4.1 8(3) ,γ =98.2 0 (3)° ,V =5 32 2 (2 ) 3,Z =2 ,Mr=2 85 5 .30 ,Dc=1 .782 g·cm-3,F(0 0 0 ) =2 86 0 ,R =0 .0 71 9,wR =0 .1 983。标题化合物由 1个环戊二烯、4个Bu4N+阳离子和 1个 [SiMoVI11MoVO40 ]4 -阴离子构成。
Resumo:
用层流恒界面池研究了CA-12萃取钇的动力学。测定了搅拌速度、酸度、萃取剂浓度、温度对萃取速率的影响。测得CA-12萃取钇的活化能为48.96kJ/mol,此过程属于化学反应控制。当CA-12中加入少量的P507时,其活化能降至23.19kJ/mol。萃取过程由化学反应控制转变为扩散和化学反应混合控制。
Resumo:
The characterization of free base porphyrin 2,3,7,8,12,13,17,18-octakis(hexyl-thio) tetraazaporphyrin (H(2)OHTTAP) and its zinc(II) complexes [Zn(II)OHTTAP] containing eight thioether groups at the beta -pyrrole positions of the macrocycle was reported. Results obtained by cyclic voltammetry and differential pulse voltammetry indicated a five-electron reduction in five steps for each complex. They were oxidized in two single-electron-transfer steps to yield pi -cation radicals and dications and reduced in three single-electron-transfer steps to yield pi -anion radicals, dianions and trianions, respectively. The redox property of H(2)OHTTAP was unusual as compared to porphyrins (PPs) and phthalocyanines (Pcs). Each process was monitored by in situ thin-layer spectroelectrochemistry, which indicated that only the Ligand was electroactive. The existence of the eight hexylthio groups was responsible for the intrastack interactions and enhanced intracolumnar and intercolumnar electron motions, resulting in improved conductivity. Copyright (C) 2001 John Wiley & Sons, Ltd.
Resumo:
采用光化学法合成一种有机-无机电荷转移盐,(HMDH2)[H2PMo12O40]·AA·3H2O·DMF(HMD = 1,6-己二胺,AA = 乙醛,DMF = N,N-二甲基甲酰胺)超分子化合物。用元素分析,IR,固体漫反射电子光谱,ESR进行了表征。X-射线四圆衍射测定其晶体结构属三斜晶系,空间群 Pī,Mr=2081.68,晶胞参数a = 14.092(3),b =14.347(3),c =14.358(3)?,α=75.10(3),β=80.70(3),γ=80.73(3)°,V=2746.6(10)?3,Z=2,Dc=2.517g/cm3,F(000)=1970,μ(MoKα)=2.766mm- 1,全矩阵最小二乘法修正至R=0.0832,wR=0.2638。标题化合物是由1个质子化的1,6-己二胺、12-钼磷混合价杂多阴离子 [PMo12O40]4ˉ、3个水分子、2个乙醛分子和1个二甲基甲酰胺分子构成。
Resumo:
以金属硝酸盐为反应原料 ,分别采用柠檬酸 凝胶法、共沉淀法和固相法制备了YAG和YAG∶RE3+ (RE =Eu ,Dy) (1% ,摩尔分数 )发光粉 ,并通过XRD ,TG DTA和发光光谱对样品进行了表征。柠檬酸 凝胶法、共沉淀法和固相法制备的YAG和YAG∶Eu的晶相形成温度分别是 80 0和 90 0℃。Eu3+ 在非晶态和晶态YAG中其激发和发射光谱有明显差异 ,在一定温度范围内 ,发光强度随烧结温度的升高而增强。由于碳杂质的存在 ,90 0和 10 0 0℃下柠檬酸 凝胶法制备样品的发射强度较其他两种方法低。
Resumo:
The reaction of [Cp*RhCl2](2) 1 with dilithium 1,2-dicarba-closo-dodecaborane(12)-1,2-dithiolate (a) and -diselenolate (b) afforded the 16-electron rhodium(III) half-sandwich complexes Cp*Rh[E2C2(B10H10)] [E=S (3a), Se (3b)]. The 18-electron trimethylphosphane rhodium(III) half-sandwiches Cp*Rh(PMe3)[E2C2(B10H10)] 4a-c were prepared from the reaction of Cp*RhCl2(PMe3) 2 with the same dichalcogenolates, including the ditelluride (c). The complexes 4a,b could also be obtained from the reaction of 3a,b with trimethylphosphane. The molecular geometry of 4b was determined by X-ray structural analysis. The 16-electron complexes 3 an monomeric in solution as shown by multinuclear magnetic resonance (H-1-, B-11-, C-13-, P-31- Se-77-, Rh-103-, Te-125-NMR). also in comparison with the data for the trimethylphosphane analogues 4a-c and for 6a in which the rhodium bears the eta(5)-1,3-C5H3 Bu-t(2) ligand. The Rh-103 nuclear shielding is reduced by 831 ppm (3a) and 1114 ppm (3b) with respect to the 18-electron complexes 4a,b. Similarly, the Se-77 nuclear shielding in 3b is reduced by 676.4 ppm with respect to that in 4b. (C) 1999 Elsevier Science S.A. All rights reserved.
Resumo:
在几种不同的助熔剂的作用下合成了BaAl12O19:Mn发光体,XRD谱显示助熔剂不仅有利于基质的结晶成核,而且对基质的不同晶面的生长也有影响.其UV光谱表明不同的助熔剂对其发光的影响不一样,H3Bo3不利于其发光,AIF3对其发光的提高不大,BaF2则可以较大地增加其发光强度.其VUV光谱显示在150nm附近有较强的激发证实了其可成为用于PDP的荧光粉之一.
Resumo:
A novel organic-inorganic composite film was formed by attaching Keegin-type heteropolyanion, SiW12O404- (devoted briefly as SiW12), on a glassy carbon electrode derivatized by 4-aminophenyl group. The composite film has an ionic bonding character between SiW12 and the surface amino group, which greatly improves the Blm stability and exhibits a more reversible electrochemical behavior. The modified electrode offers an excellent and stable electrocatalytic response for the reduction of nitrite. Possible mechanism was provided for the reaction of nitrite with SiW12O404-/aminophenyl composite film.
Resumo:
The crystal structure of H3PMo6W6O40 3C2H6O was determined by X-ray crystallography and refined to R = 0.0698 based on 2279 observed reflections to give unit cell parameters a = 16.48(2)Angstrom, c = 25.205(5)Angstrom , gamma = 120 degrees, hexagonal, space group R (3) over bar. The organic solvent molecules were characterized also by IR, H NMR spectra. Weak interaction existed between the organic solvent and the heteropoly acid in the secondary structure. The novel compound showed different behaviours in solubility, oxidizability and photosensitivity in comparison with classical dodeca heteropolyacid of molybdenum and tungsten. (C) 1998 Elsevier Science B.V.
Resumo:
在室温至450℃范围内,考察了H3PW12O40·29H2O的受热相变情况.结果表明,杂多酸中所含沸石水和结晶水很容易失去,且失水程度与其所处环境有关.以IR、TG-DTA、XRD以及SEM等表征了不同含水量的杂多酸,表明其晶体结构及外观均因失水而发生了相应的变化.
Resumo:
用电解法制备了有机-无机自由基盐(DBTTF)6PMo12O40·2H2O.用红外光谱、电子光谱和电子自旋共振谱进行了表征,测定了其磁化率、导电性和单晶的晶体结构.该晶体属三斜晶系,P1空间群.晶胞参数为a=1.3787(7)nm,b=1.4204(2)nm,c=1.5702(2)nm,α=104.570(8)°,β=103.41(2)°,γ=95.80(2)°,V=2.853(2)nm3,Z=1,Dc=2.142Mg·m-3,R=0.0727.
Resumo:
采用柠檬酸配合法合成了结构呈层状ABO_3的La_4BaCu_5O_(12)复合氧化物,并以它为基体合成了一系列Mn取代Cu的样品(La_4BaCu_(5-x)Mn_xO_(12),x=1~5。)并利用XRD,IR进行了结构表征,结果表明其均为5层的ABO_3结构.利用H_2-TPR考查了掺杂Mn以后样品的氧化还原性能的变化,发现由于Mn的掺杂使Cu明显的容易还原还考查了样品对NO+CO反应的催化活性,结果表明反应的活性中心是Cu离子,但加入适量的Mn离子可以使活性提高.
Resumo:
It was found that vitamin B-12 could be strongly adsorpted on the anodized glassy carbon electrode to form a vitamin Thy-modified glassy carbon electrode. The modified electrode is stable in a wide pH range. The electrochemical characteristics of the modified electrode were studied in details. In addition, it was found that the reduction of oxygen could be catalyzed by the modified electrode to form H2O2. An EC mechanism was suggested for the process, and the follow up chemical reaction might he the rate determined step.
Resumo:
The electrochemical studies on vitamin B-12 and its derivatives were reviewed in this paper. The importance of electrochemical studies for explaining the mechanism of B-12 coenzyme in body was discussed. The latest results of electrochemical studies on vitamin B-12 and its derivatives was reviewed. A prospect for the electrochemical studies in vitamin B-12 and its derivatives was suggested.