Electrochemical and in situ spectroelectrochemical behavior of 2,3,7,8,12,13,17,18-octakis(hexyl-thio) tetraazaporphyrin (H(2)OHTTAP) and (Zn(II)OHTTAP)

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.

己二胺-12-钼磷酸电荷转移盐的光化学合成与晶体结构

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。

用3种方法合成Y_3Al_5O_(12)∶RE~(3+)(RE=Eu,Dy)发光粉的对比研究

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。

16-and 18-electron Cp*Rh complexes with 1,2-dicarba-closo-dodecabofane(12)-1,2-dichalcogenolato ligands, as studied by multinuclear magnetic resonance

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.

助熔剂对发光体BaAl_(12)O_(19):Mn结构及发光的影响

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．

Preparation of a composite film electrode containing 12-tungstosilicic acid and its electrocatalytic reduction for nitrite

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.

The structure and properties of 12-heteropolyacid of molybdenum and tungsten (H3PMo6W6O40) solvated by dimethyl ether

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.

12-磷钨杂多酸受热相变的研究

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.

有机-无机自由基盐(DBTTF)_6PMo_(12)O_(40)·2H_2O的合成、性质和晶体结构

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．

层状复合氧化物La_2BaCu_(5-x)Mn_xO_(12)的表征及在催化消除NO中活性的研究

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.

Study on the Property of Vitamin B-12-Modified Electrode and its Electrocatalysis for the Reduction of Oxygen

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.

Electrochemical studies on vitamin B-12 and its derivatives

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.

La_2O_3-Ni/SrAl_(12)O_(19)催化剂上甲烷与二氧化碳重整反应的研究

采用ＸＲＤ、ＵＶ－ＤＲＳ、Ｈ２－Ｏ２滴定、ＴＰＲ、吡啶吸附红外光谱等技术，研究了Ｌａ２Ｏ３助剂对Ｌａ２Ｏ３－Ｎｉ／ＳｒＡｌ１２Ｏ１９催化剂的还原性、表面酸性、金属镍的分散度和抗烧结能力，以及对催化甲烷与二氧化碳重整制取合成气反应性能的影响．结果表明，在负载型的镍催化剂中，添加Ｌａ２Ｏ３助剂，能够削弱金属组分与载体之间的相互作用，降低催化剂的还原性，提高金属镍在催化剂表面的分散度和在反应过程中的抗烧结能力，降低催化剂表面酸性．关联甲烷与二氧化碳重整反应活性的结果，发现影响负载型镍催化剂的反应活性、稳定性和积炭性质的主要因素是金属镍的分散状态，而不是催化剂表面酸性．Ｌａ２Ｏ３主要是通过改变镍的分散度来影响催化甲烷与二氧化碳重整反应活性的．

维生素B_(12)修饰电极及其催化氧还原性质的研究

发现维生素B12能吸附在经阳极化处理的玻碳电极上，从而制成稳定的维生素B12修饰玻碳电极．详细研究了此电极的电化学性质．并发现此修饰电极能有效地催化分子氧的二电子还原.