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1.
Introduction Flavonoids exist widely in edible plants, and have pharmacological activity. They played a major role in the successful medical treatments at ancient times, and their uses have been persevered up to now.1-3 Flavonoid sulfates were found in a large number of plant species. They occupy an important position in the field of natu-ral products chemistry since they provide structures consisted of organic and inorganic components. The pharmacological assay revealed that flavonoid sulfat…  相似文献   

2.
1 INTRODUCTION The investigation of Shiff base complexes con- taining sulfur and complexes of amino acid Schiff bases[1, 2] has recently aroused considerable interest due to their antiviral, anticancer and antibacterial activities. Taurine, known as 2-aminosulfonic acid, is indispensable to human beings and plays an im- portant role in physiological functions. In this con- tribution, we present the synthesis and crystal struc- ture of a new binuclear Zn(II) dimmer with a tri- dentate Sc…  相似文献   

3.
1 INTRODUCTION The controlled assembly of inorganic and coordination polymers from simple building blocks is an important challenge in the design of high- dimensionality systems. In the crystal engineering 'toolbox'[1], hydrogen bonding moieties are perhaps the implements used the most in the design of such supramolecular systems[2], and have been particularly strongly applied towards the synthesis of molecular magnetic materials[3~6]. Copper complexes play an important role in catalyzin…  相似文献   

4.
1 INTRODUCTION Orotic acid (H3dtpc), an important pyrimidine derivative as the effective precursor in the biosynthesis of pyrimidine base of nucleic acids in living organisms, plays a unique role in bioinorganic and pharmaceutical. Aside from the biological interest, orotic acid is also interesting in coordination chemistry. Its ketonic and enolic tautomers along with asymmetric geometry make it to be a very good versatile polydentate ligand[1~5]. The incorporation of metals into supram…  相似文献   

5.
1 INTRODUCTIONAlthough vanadium plays an increasingly recognized role as a biometal[1~4], little is known about the structure and function of vanadium compounds in living organisms. A classical and nevertheless rapidly developing field of application for oxovanadates and related compounds is their use as catalysts in polymerization and oxidation reactions[5,6], and recent interest has focused on oxovanadates as model compounds for the interaction of oxovanadates with the active sites of en…  相似文献   

6.
The enthalpy change of formation of the reaction of hydrous dysprosium chloride with ammonium pyrrolidinedithiocarbamate (APDC) and 1,10-phenanthroline (o-phen·H2O) in absolute ethanol at 298.15 K has been determined as (-16.12±0.05) kJ·mol-1 by a microcalor-meter. Thermodynamic parameters (the activation enthalpy, the activation entropy and the activation free energy), rate constant and kinetics parameters (the apparent activation energy, the pre-exponential constant and the reaction order) of the reaction have also been calculated. The enthalpy change of the solid-phase reaction at 298.15 K has been obtained as (53.59±0.29) kJ·mol-1 by a thermochemistry cycle. The values of the enthalpy change of formation both in liquid-phase and solid-phase reaction indicated that the complex could only be synthesized in liquid-phase reaction.  相似文献   

7.
杨锐  何水样  武望婷  陈凤英  胡荣祖 《中国化学》2006,24(12):1731-1736
Europium(Ⅲ) compound with 2-oxopropionic acid salicyloyl hydrazone (C_(10)H_(10)N_2O_4,H_3L) and 1,10-phenan-throline (C_(12)H_8N_2,phen) has been prepared.A yellow prismatic crystal of the compound was obtained,and themolecule crystallized in the triclinic space group P-1.There are two 9-coordinated complex molecules in everystructure unit,where every Eu atom is coordinated by three water molecules and two tridentate C_(10)H_(10)N_2O_4 ligands,forming two stable pentacycles.The coordination polyhedron around Eu~(3+) was described as a single cap squareantiprism.In the crystal cell,there are one free 1,10-phenanthroline and four water molecules.The thermaldecomposition of the compound and its kinetics were studied by non-isothermal thermogravimetry.The Kissinger'smethod and Ozawa's method were used to calculate the activation energy value of the first-step decomposition.Thestages of the decompositions were identified by TG-DTG-DSC curve.The non-isothermal kinetic data were ana-lyzed by means of integral and differential methods.The possible reaction mechanism and the kinetic equationswere investigated by comparing the kinetic parameters.  相似文献   

8.
This paper reports two lanthanide complexes of formula (C_9H_7)Ln(C_8H_8)·(THF)_2 whereLn is Pr or Nd,C_9H_7 is indenyl,and C_8H_8 is cyclooctatetraene (COT).The complexes were preparedby the reaction of LnCl_3 with K(C_9H_7) and K_2(C_8H_8) in THF.(C_9H_7)Pr(C_8H_8)·(THF)_2 crystallizes inTHF at - 15℃ in the monoclinic space group P2_1:with unit cell dimensions a=8.446(0),b=10.083(2),c=13.407(3),β=105.48(1)°,V=1100.43(35)~3,Dc=1.52g/cm~3 and Z=2.The final R valueis 0.033,R_w value is 0.030,respectively.In (C_9H_7)Pr(C_8H_8)·(THF)_2 a five-membered ring centroid ofC_9H_7,the C_8H_8 ring centroid and the two oxygen atoms from the two THF molecules form a distortedtetrahedral geometry around the metal.  相似文献   

9.
<正> Preliminary information. Vanadium compounds plays an important role in catalysis since they have a property of easily changeable oxidation states. As a part of our study on vanadium compounds, the crystal structure of the title compound is reported, which is prepared by the reaction of (C_3H_(12)N_2)_2-V_2O_7, NaVO_3 with KOH in an aqueous solution.  相似文献   

10.
A systematic study of the structural and superconducting behavior of the high Tc compounds YBa_1Cu_(1.9)M_(0.1)O_(7-y) has been performed where M=Ti, V, Mn, Fe, Co, Ni, Zn, Zr, Nb, Mo, In and Sn. Structural analysis shows that most replacements somewhat modify the YBa_2Cu_3O_(7-y) lattice parameters in the orthorhombic structure, with the exception of Fe and Co which transit into tetragonal phase. Although the 1D Cu-O chains are destroyed, the depressed Tc remain within 73 to 76K in the case of Fe and Co. However. the substitution of Ni and Zn on the Cu_2 sites appears to strongly decrease Tc whereas their structure remains orthorhombic. This indicates that the 2D Cu-O planes play a very important role in the transportation of superconducting electrons but the 1D Cu-O chains play a role not only in supplying carrier number but also in coupling the Cu-O planes.  相似文献   

11.
The thermal behavior of the complex Pr[(C5H8NS2)3(C12H8N2)] in a dry nitrogen flow was examined by TG-DTG analysis. The TG-DTG investigations indicated that Pr[(C5H8NS2)3-(C12H8N2)] was decomposed into Pr2S3 and deposited carbon in one step where Pr2S3 predominated in the final products. The results of non-isothermal kinetic calculations showed that the decomposition stage was the random nucleation and subsequent growth mechanism (n = 2/3), the corresponding apparent activation energy ?was 115.89 kJ·mol-1 and the pre-expo-nential constant ln[A/s] was 7.8697. The empirical kinetics model equation was proposed as/(α) =3/2(1-α)[-ln(1-α)]1/3.The X-ray powder diffraction patterns of the thermal decomposition products at 800℃under N2 atmosphere show that the product can be indexed to the cubic Pr2S3 phase. The transmission electron microscopy (TEM) of the final product reveals the particle appearance of a diameter within 40 nm. The experimental results show that the praseodymium sulfide nanocrystal can be prepared from thermal decomposition of Pr[(C5H8NS2)3(C12H8N2)].  相似文献   

12.
<正> Introduction. The complexes of Mo(V) and oxalate are found to exist in several various configurations. As an anologous compound for the activecenter of Mo enzymes they have attracted broad attention. It was found by Sobczak and Ziolkowski in 1976 that these types of complexes had a higher catalytic selectivity in the epoxidation of olefine by hydroperoxides  相似文献   

13.
A new complex has been synthesized with o-methylbenzoyl-benzoic acid(HL) and 1,10-phenanthroline(phen) in the mixture of water and ethanol. It crystallizes in monoclinic, space group C2/c with a = 13.6328(18), b = 17.7876(18), c = 19.998(2), β = 104.720(4)o, C54H48N4O11Zn, Mr = 994.33, V = 4690.2(9)3, Dc = 1.408 g/cm3, Z = 4, F(000) = 2072, μ(MoKα) = 0.59 mm-1, R = 0.0736 and wR = 0.2029. The crystal structure shows that the zinc ions are coordinated with two oxygen atoms from two HL molecules and four nitrogen atoms from two phen molecules, forming distorted octahedral coordination geometry. The fluorescent and thermal stability properties of the complex are studied. The result shows that it has one fluorescent emission band at around 412 nm. In addition, the complex is stable under 210 ℃.  相似文献   

14.
《结构化学》2019,38(11)
A new europium(Ⅲ) complex Eu_2(C_(15)H_(11)O_3)_6(C_(12)H_8N_2)_2 has been synthesized with 2-(4-Methylbenzoyl)benzoic acid and 1,10-phenanthroline as ligands. Crystal data for the complex are as follows: monoclinic, space group P21/n, a = 15.1238(5), b = 13.5928(4), c = 22.9840(7) ?, β = 104.132(3)o, V = 4582.0(2) ?~3, D_c = 1.522 g/cm~3, Z = 4, μ(Mo Kα) = 1.433 mm~(-1), F(000) = 2128, the final R = 0.0447 and wR = 0.0826. The Eu(Ⅲ) ion is coordinated by eight atoms to give a distorted square antiprism coordination geometry. The complex shows two intense fluorescence emission bands arising from the transitions of Eu3+: 5 D0 → 7 F1(594 nm) and 5 D0 → 7 F2(617 nm). The complex is an antiferromagnetism system in the range of 150~300 K. Also reported in the paper is the thermal stability property of the title complex.  相似文献   

15.
1INTRODUCTION Recently,cyano-bridged lanthanide-transition me-tal complexes have been extensively investigateddue to their potential applications as precursors in the preparation of rare earth orthoferrites,fluores-cent and magnetic materials[1].Various complexes of this system have been obtained in order to ex-plore the relations between structures and pro-perties by using different ligands,such as DMF,4,4?-bipy,and so on,to fill the coordination sites of lanthanide ions[2~9].But up to…  相似文献   

16.
Introduction Molecules containing different kinds of metal ions play an important role in molecular magnetism.1-3 So considerable attention has been paid to synthesizing heteronuclear complexes.1-4 As a potential bridging ligand, thiocyanate can coordinate to a harder metal center and softer ones with N and S atoms respectively. The complexes of thiocyanate and representative hard acidFe(III) ions usually have a six-coordinate octahe-dral structure such as [Fe(SCN)n]3-n and (Bu4N)4[Ag2-F…  相似文献   

17.
[Sm(C7H5O3)2(C4H6NO2S)]·2H2O was synthesized from the reaction of samarium chloride hexahydrate with salicylic acid and thioproline,and characterized by IR,elemental analysis and thermogravimatric analysis.The standard molar enthalpies of the solutions of SmCl3·6H2O(s),2[C7H6O3(s)],[C4H7NO2S(s)] and [Sm(C7H5O3)2·(C4H6NO2S)·2H2O(s)] in a mixed solvent of absolute ethyl alcohol,dimethyl formamide(DMF) and 3 mol/L HCl were,respectively,determined by calorimetry to be Δs Θ [SmCl3·6H2O(s),298.15 K]=(-46.68±0.15)...  相似文献   

18.
<正> Introduction. Tertiary diphosphine-cyclopentadienyl-nickel(Ⅱ) complexes were first synthesized by Sato (Sato, et al., 1971), and their boronhydrides were prepared by Zhang (Zhang, et al., 1983). Here we report the crystal structure of the title compound in Order to correlate the reactivity of this type of compounds with their structures and bondings.  相似文献   

19.
1 INTRODUCTION Coordination polymers have attracted the atten- tion of chemists, physicists, and materials scientists owing to their fascinating structures and potential functional applications in the last decade[1~4]. The bridging ligands play a central role in constructing functional coordination polymers, and weak nonco- valent interactions like hydrogen bonding or π-π stacking plays an important role in molecular self- assembly[5~7]. As a multidentate and rigid ligand with multi-pr…  相似文献   

20.
<正> INTRODUCTION. Ipomoea Hardwickii Hemsl (Ⅰ) belongs to Convolvulaceae, and its seed may be used as an anodyne. Ipoharine and Ipohardine were obtained by Reinickate method from the aqueous solution of Ⅰ. The structure of the title compound has been determined by X-ray crystal structure analysis. The structure of the cation (C_(15)H_(16)NO)~+ is reported here for the first time.  相似文献   

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