Molecular structure of imidazolate bridged binuclear zinc complex and its single crystal ESR spectra doped with bridged Cu—Zn complex

The X-ray crystal structure of [(dtma)ZnImZn(dtma)]ClO_4·2.5H_2O (Hdtma=4-Diethyl-enetriamineacetic acid) was determined.The crystal is of orthorhombic,space group Pbcn with a-14.104(5),b=14.897(5),c=25.384(9),and Z=8.The least-square refinement of the structureleads to conventional R factor of 0.066.The magnetic properties of [(dtma)CulmZn(dtma)]CIO_4·2.5H_2Owere investigated.From the single crystal ESR spectra of Zn—Im—Zn dimer doped withCu—Im—Zn complex,the anisotropic g and A tensors and electronic spin-density of the Cu—Zncomplex are obtained and the bonding nature of Cu is discussed.     

三维异双金属混合桥氰化物的合成和结构

高Tc分子磁体的研究近年来受到重视，其中尤以双过渡金属氰化物的研究发展异常迅猛．继Verdaguer[1]报道了Tc=90K的CsNi[Cr（CN）6]2·H2O配合物后，Verdaguer[2]和Girlami等[3]又分别报道了一系列TC=240、230、190K的同或异双过渡金属含CN配合物．Fujishima等[4]报道的具有磁光效应的K0.2Co1.4[Fe（CN）6]·6.9H2O配合物使分子磁性应用于分子电子学领域成为可能．但上述化合物均为粉末，未能获得其晶体结构，因此无法阐明其磁交换机理，亦难以发展成为晶须及其它异型磁性材料．为弄清混合金属氰化物成键性质、CN桥中介磁交换机…     

RbBr/CsBr-CH3OH/C2H5OH-H2O三元体系的溶解度

采用自制的相平衡研究装置, 测定了RbBr-CH3OH/C2H5OH-H2O和CsBr-CH3OH/C2H5OH-H2O四个三元体系在25、35、45 ℃三个温度下的平衡溶解度;同时得到了四个三元体系饱和溶液中不同盐浓度下的折光率数据. 实验结果表明,在所有的体系中, 随着甲醇或乙醇质量分数的增加, RbBr和CsBr 在水中的溶解度逐渐降低; 并且折光率也逐渐减小. 用经验关联方程对溶解度进行了拟合, 同时给出了CH3OH 和C2H5OH 分别对RbBr和CsBr的盐析率曲线.     

非化学计量金属间化合物DO3型Fe3Al热力学性质

用以CaF2单晶为固体电解质的电池电动势(EMF)法测定了720～850 K温度区间内(－)Pt|Ir|Al_0.85Sn_0.15,Na₃AlF₆|CaF₂|Al_xFe_1－x(x=0.23～0.33),Na₃AlF₆|Ir|Pt(＋)电池电动势,通过DO₃型Fe₃Al的粉末化以及选用富Al合金Al_0.85Sn_0.15作为参比电极,使电池反应较快地达到热力学平衡,EMF测量前后工作电极的X射线衍射分析证明没有化学变化发生.计算了DO₃型Fe₃Al非化学计量金属间化合物均相范围内组元Al的活度及Al的偏摩尔热力学函数ΔG_Al、ΔH_Al、ΔS_Al ,基于Gibbs-Duhem方程计算了DO₃型Fe₃Al中另一组元Fe的活度和偏摩尔Gibbs自由能.计算了750 K时DO₃型Fe₃Al相中Al的扩散热力学因子,在化学计量比成分(xAl=0.25)附近Fe₃Al相中Al扩散的热力学因子达到最大值.     

Construction of metal-organic frameworks through coordination and hydrogen bonding interactions: Syntheses, structures and photoluminescent properties of metal complexes with macrocyclic ligand

A macrocyclic ligand L with two diethylenetriamine units linked by two rigid biphenylene spacers was used as building block for construction of metal-organic frameworks. A silver(I) complex with macrocyclic and open-chain mix-type ligands [Ag₂(L)(L′)](ClO₄)₂ (1) [L′=1,6-bis(4-imidazol-1′-ylmethylphenyl)-2,5-diazahexane] was obtained by reaction of L and L′ together with AgClO₄·H₂O. It is interesting that the open-chain tetradentate ligand L′ only served as a bidentate ligand to bridge the Ag₂L units into an infinite one-dimensional (1D) cationic chain. Neutral 1D chain coordination polymer [Cu₂(L)(μ-SO₄)₂]·3H₂O·3MeOH (2) is formed by sulfate bridges between the neighboring Cu₂L units. When L reacted with nickel(II) sulfate instead of copper(II) sulfate, a monomacrocycle molecular complex [Ni₂(L)(H₂O)₄(SO₄)₂] (3) was obtained in which the sulfate anion acts as monodentate ligands rather than as bridges. When Cd(II) salts were used for the reactions with L, another two neutral 1D coordination polymers, [Cd₂(L)(μ-Cl)₂Cl₂]·2H₂O (4) and [Cd₂(L)(μ-Br)₂Br₂] (5), with the same structure were isolated. All the synthesized complexes exhibit three-dimensional framework structures linked by various hydrogen bonds. The photoluminescent properties of the synthesized complexes were studied in the solid state at room temperature, and the Ag(I) and Cd(II) complexes were found to show strong blue luminescence.     

Anion binding in aqueous solutions by N-(Isonicotinamido)-N'-phenylthiourea-based simple synthetic neutral receptors. role of the hydrophobic microenvironment of the receptor molecule

N-(Isonicotinamido)-N'-(substituted-phenyl)thioureas (1a-e, substituent X = p-OCH3, p-CH3, H, m-Br, and m-CF3) have been designed as neutral receptors, in order to prove the influence of conformational issues on the ability to bind anions in aqueous solutions. Compounds 1a-e were shown to create a hydrophobic microenvironment around the thiourea group, favoring hydrogen bonding interactions, by evidence from quantum mechanic calculations, thermodynamic analysis, NMR aromatic current shielding, and comparative anion binding. Referring to N-(substituted-benzamido)thioureas (2a-e, substituent Y = H, m-Cl, m-NO2, m,m-Cl,Cl, and p-NO2), we showed that, for the hydrophobic microenvironment to be operative in aqueous solutions, the amido -NH proton needs to be acidic enough.     

氧原子和羟基在Ni低指数表面的吸附动力学研究

应用5-参数Morse势方法模拟了O－Ni表面相互作用势,考察了氧原子在镍三个低指数表面的吸附特性.同时构造了羟基与Ni（100）、Ni（110）和Ni（111）表面相互作用的推广LEPS势,获得了羟基在表面的吸附位、吸附几何、结合能及本征振动等数据.理论结果表明,羟基垂直吸附于镍表面的高对称位是稳定的,垂直吸附于Ni（100）表面4-重洞位的吸附能为96.98 kJ•mol－1,垂直吸附于Ni（111）表面3-重洞位的吸附能为96.00 kJ•mol－1,在Ni（110）表面存在两种吸附态：垂直吸附于长桥位的吸附能为99.38 kJ•mol－1,倾斜14°吸附于赝势三重位吸附能为96.98 kJ•mol－1.理论结果与实验结果符合得较好.     

Electrospray Mass Spectrometric Study on Complexation of Transitional Metal Ions with Oligobipyridine Ligand

Positive-ion mode electrospray mass spectrometry (ES-MS) was used to investigate the reaction of oligobipyridine ligand L (L = 5,5'-bis[2-(2,2'-bipyridin-6-yl)ethyl]-2,2'-bipyridine) with M(ClO₄)₂ in various mole ratios [M = Fe(II), Co(II), Ni(II) and Cu(II)]. The results indicate that the oligobipyridine L coordinated to the transitional metal ions to form mononuclear complexes. The ES mass spectra of isolated complex [FeL₃](PF₆)₂ were measured under various electrospray conditions to examine the influence of the spray voltage, capillary temperature, capillary voltage, and tube lens offset on the fragmentation of the complex in electrospray ionization process. The results show that the fragmentation was mainly controlled by the capillary temperature, capillary voltage, and tube lens offset potential for Finnigan MAT LCQ system. The present study confirmed that the ES-MS is a powerful technique for determining the species existing in solution and for investigation of the reaction between oligobipyridine and transitional metal ions.     

A novel electrochemical deposition route for the preparation of Zn1−xCdxO nanorods with controllable optical properties

Here we explored a novel and facile electrochemical route for the preparation of Zn_1?xCd_xO (x is atomic percentage of Cd) nanorods with controllable optical properties. The Zn_1?xCd_xO nanorods can be routinely obtained when the electrochemical deposition was carried out in solution of Zn(NO₃)₂ + Cd(NO₃)₂ + citric acid at ?1.0 V (vs SCE). EDS results demonstrated that Cd, Zn, and O elements existed in the deposits, and ternary Zn_1?xCd_xO compounds were obtained. XRD results showed that Zn_1?xCd_xO nanorods were pure ZnO wurtzite structures. HRTEM and SAED analyses confirmed that Zn_1?xCd_xO nanorods were single-crystalline. The optical properties of Zn_1?xCd_xO nanorods were investigated in this paper.     

两体扰动势和H2O通道反应的三原子体系解析势

提出了两体扰动势的概念.通过两体扰动势构造多原子相互作用体系解析势的理论方法,获得了非线性三原子H2O相互作用体系的解析势函数.用势能面正确描述了O(1D)+H2→H2O→OH+H通道反应的性质.理论分析和实验结果非常符合.该方法比较容易推广构造多原子相互作用体系解析势.