银电极表面氧化物的形成与转变

金属银是碱性电池的重要电极材料,人们已对它在碱性水溶液中的电化学反应进行广泛的研究,但其阳极氧化过程的分析以及氧化产物的鉴定至今仍是众说不一。为此,本文采用现场电化学X-射线衍射技术并配合循环伏安实验进行了研究。现场X-射线衍射实验在一个特制的有机玻璃电解池中进行。整个电解池系统犹如普通粉末样品架一样安放干衍射仪的样品台上,其中透射X-射线的窗片为聚酯薄膜。研究电极是将15×10×2mm~3的银片(纯度为99.99%)用环氧树脂灌封而成,并使用饱和甘汞电极     

A Novel Route to Synthesize Nano-crystalline Ba0.5Sr0.5Co0.8Fe0.2O3-δ Perovskite Oxide at High Temperature

BSCF, a composite oxide with mixed oxygen ionic and electronic conductivity at high temperature, has received increasing attention since it was first developed as the oxygen permeable membrane and the membrane reactor for partial oxidation of natural gas to syngas by Shao et al.2, 3. It shows high oxygen permeability and catalytic activity for the reduction of the oxygen4-6. Very recently, it is also successfully applied as the cathode material in intermediate temperature solid oxide fuel cel…     

Novel Monomeric Phenanthroline - Thallium(III) Complexes Multinuclear NMR Characterization in Organic Solvents

Thallium(III) complexes with nitrogen donor ligands constitute an interesting field in coordination chemistry. Phenanthroline is an extremely stiff organic ligand. The stability constants of its coordination compounds with Tl(III) have been investigated in aqueous solution by potentiometer1. 205Tl NMR technique has provided an effective method to study the thallium(III) solution chemistry. Thallium(III) coordination chemistry has attracted considerable attention recently for its ric…     

Theoretical Study on Reactivity of Electron Transfer in Model—System of Oxidation of α—Amino Carbon—centered Radical by O2

Electron transfer reaction between a simplified model model molecule of α－amino carbon-centered radical and O2 has studied with ab initio calculations at the MP2/6-31 G^**//UHF/6-31 G^** level,The reactant complex and the ion pair complex have been optimized and employed to perform calculation of the reaction heat and the reorganization energy,Solvent effects have been considered by applyning the conductor-like screening model,Theoretical results show that the highly endothermic charge separation process ,in which one electron transfers from the α－amino carbon-centered radical to O2,so as to form an ion pair complex,is difficult to occur in gas-phase,By apply-ing an external electronic field to prepare the charge-locallized molecular orbitals,the charge-separated state has been obtained using the initial-guess-induced self-consistent field technique,The theoretical investigations indicate that the solvent effect in the process of the oxidation of α-animo carbon-centered radical by O2 is remarkable.From the rate constant estima-tion ,it can be predicted that the oxidation of the model donor molecule by O2 can proceed,but not very fast.A peroxyl radi-cal compound has been found to be a competitive intermediate in the oxidation process.     

Structures, relative stability and dissociation of [Si,N,C,O]2+isomers

Fifteen isomers of [Si,N,C,O]2+ system are obtained at UB3LYP/6-311G(d) and UCCSD(T)/6-311+G(2df) (single-point) levels. The analyses are made for predicting the structures of optimized isomers, while ionic fragments with lower energies are suggested. The calculatedresults indicate that linear isomer SiNCO2+(2П) is thermodynamically the most stable species in [Si,N,C,O]2+ system, followed by linear SiOCN2+ (2П), SiCNO2+ (2П), and SiC(NO) (2A") with NCO three-membered ring. The order of stability of several kinetically stable isomers is SiNCO2 >SiCNO2+ (2П)>SiOCN2+ >SiC(NO)2+>OSiNC2+ (2П). The obtained results by analyzing the isomerizations and ionic fragment patterns show that the signal peaks of [Si,N,C,O]2+ are attributed to the contribution of linear SiNCO2+ species, which is metastable and can dissociate to the ionic fragments in the mass spectrometry experiments.     

Stereoselective Synthesis of （Z）-5-（Trideca-4-enyl）resorcinol and Gibbilimbols A-D

(Z)-5-(Trideca-4-enyl)resorcinol (1) and gibbilimbols A-D(2-5) were synthesized in 47%-60% yields over 6 steps from commercially available starting materials. The Wittig reaction of various alkyl phosphonium bromides with appropriate aldehydes in the presence of potassium tert-butoxide (t-BuOK) in anhydrous THF solution at room temperature served as the key step, and the result showed that only (Z)-configuration olefins were formed by this procedure. The synthesis of the (Z)-5-(trideca-4-enyl)resorcinol (1) was reported for the first time.     

Synthesis, Characterization, Spectroscopic and Electro-chemical Properties of New Mono- and Binuclear Copper(I) Complexes with Substituted 2,2''''-Bipyridine

Introduction Copper(I) complexes have received much attention for their being less expensive and environmentally friendly, various coordination geometry, rich photo-chemical and photophysical properties.1-7 It is well known that copper complexes with diimine (2,2'-bipy- ridine, 1,10-phenanthroline and their substituted deriva-tives designated as diimine) generally exhibit low en-ergy metal-to-ligand charge-transfer (MLCT) states lo-cated in the regions of 350650 nm (e ≈ 103—104 dm3昺ol-1昪…     

Synthesis and Crystal Structure of N,N''''-Dimethyldithio-arbamato-Copper(I) Polymer {[Cu(Me_2dtc)]_2}_n

Introduction In recent years, metal dithiocarbamate complexesremain attractive because of their possible relevance tothe nature of the sulfur-metal bond in some bimole-cules1 and their potential biological role in anti-alkyla-tion and cancer disease treatment.2 Among them, cop-per(II) dithiocarbamate complexes have been exten-sively investigated due to their rich structural magnetic,and electrochemical properties.3 However, the chemistryof copper(I) complexes of dithiocarbamates seems lesse…     

Study on Synthesis and Intercalation Behavior of Layered Zirconium Proline-N-methylphosphonate-phosphate

Zirconium proline-N-methylphosphonate-phosphate (α-ZPMPP) was prepared in the presence of HF for the first time. The α-ZPMPP sample is highly crystallized with interlayer distance of 1.52nm. The interlayer distance of complex of α-ZPMPP with n-butylamine (α-ZPMPP-BA) is in 0.45 nm larger than that of α-ZPMPP. The α-ZPMPP possesses different intercalation behavior of host-guest compound from α-ZP.     

A Novel Diamine, 4′-Phenylphenyl 4-(3′′, 5′′-Diaminobenzoyloxy)- benzoate and Longer Side-chain Polyimide

In our previous study,the polyimides with the side-chain were obtained from3,5-diaminobenzoic-4′-biphenyl ester(DABBE)1.This kind of polyimide films showed some interesting properties,such as excellent solubility,lower density,and higher tensile strength.To understand the influence of various mesogenic units,making reference to those synthesis of polyimides with side-chain2-3,in this study,a novel diamine with higher length/diameter(L/D)ratio containing aryl ester group and biphenyl unit wa…