Five novel vanadium substituted series of Dawson-type heteropoly acid H7 [As2Mo17VO62 ]·10H2O （1）, H8 [ As2Mo16 V2O62 ]· 7H2O（2）, Ha [ As2MO15 V3O62 ]·8H2O（3）, H8 [ As2Mo14 V4O62 H2 ]·7H2O（ 4 ）, H9[As2Mo13V5O62H2] ·10H2O（5） were prepared respectively in aqueous solution. When magnetic stirring and pH meter monitoring, all reactants mixed and controled different pH, then the mixture was refluxed for 10 h, later extracted by aether when it cooled, finally, it could be recrystaled by 0.5 % sulphuic acid solution, then yielded productions that we need. Compounds （ 1 ） - （5） were characterized by elemental analysis, thermogravimetic analysis （TGA）, infrared spectroscopy （IR）, ultraviolet and visible spectroscopy（UV-Vis）, X-ray powder diffraction analysis, ^51V nuclear magnetic resonance （SIV NMR） structure analysis. The study indicates that these compounds possess Dawson structures, ^51V NMR spectra reveals that V atom is polar-site substituted indeed.
A novel coordination polymers [Cu2（ETU）6]SO4（1）（ETU=ethylidene thiourea） was synthesized under solvothermal conditions.The crystal structure of the polymer was determined by X-ray diffraction: trigonal,space group R3c（No.161）,a=1.275 09（8） nm,b=1.275 09（8） nm,c=3.574 7（7） nm,γ=120°,Z=6,CCDC Number: 605501.In the structure of the polymer,each metal ion Cu（Ⅰ） coordinates to three S atoms attached to the ring of ETU forming two triangular pinwheel-shape monovalent cations[Cu2（ETU）6]+, in one of which the counter-ion SO2-4 is located.The ions with contrary charge,[Cu2（ETU）6]+ and SO2-4,are held together via the N—H…O hydrogen-bonded interactions resulting in a three-dimensional supramolecular network.
The self-assembly of clusters in inorganic systems is an interesting subject. The self-assembly of big molecules has been well established in biological systems. In addition, the coordination chemistry of metal-sulfur-nitrogen cluster complexes has been a very active and attracting field for many years as a result of the novelty and versatility of the crystal structures and reactivities of such clusters, as well as their potential applications as the models for the active sites in non-heme proteins. At the same time, there is currently considerable interest in the formation of metal complexes with heterocyclic ligands because of the diverse characteristics of ligands and their consequential wide range of applications.
Three new Keggin polyoxometalates, [Zn（phen）3]2[SiW12O40]＇5H2O（1）, [Co（phen）3]2[SiW12O40]（2） and [Ni（phen）3]2[SiW12O40].2H2O（3）（phen=1,10＇-phenanthroline） have been hydrothermally synthesized and characterized by elemental analysis, IR, crystal X-ray diffraction, thermogravimetric analyses（TGA） and fluorescence tech- niques. Complex 1, crystallized in the triclinic space group Pi, consists of one [SiW12O40]4 anion, two discrete [Zn（phen）3]^2＋ cations and five crystal water molecules. Complexes 2 and 3 have the similar configuration to complex 1, but they crystallized in the monoclinic space group C2/c. Variable-temperature magnetic susceptibilities of complexess 2 and 3 reveal antiferromagnetism and ferromagnetism, respectively.
ZHANG Yong-feng JIA Yan-yan NIE Hai-liang YAN Xing-juan WANG Li HUANG Ru-dan
Polyoxometallates Co(en) 3PMo 12O 40·8H 2O(+,-)[abbreviated as PMo 12-Co(+,-)], nanoparticles were synthesized by the chemical precipitation reaction at room temperature for the first time. They were characterized by means of elemental analyses, IR spectrometry and X-ray diffraction. The images of scanning electron microscopy(SEM) and the results of calculation by using the Scherrer equation for the line widths of the XRD patterns were used to estimate the average particle size of the powder products, which was 40 nm. The results show that the nanoparticle size was affected by starting materials′ concentrations. The particles had a small size and a narrow distribution, when the concentrations of H 3PMo 12O 40·24H 2O and Co(en) 3I 3·H 2O were around 1.7×10 -4 and 1.0×10 -3 mol/L, respectively. When the concentration was increased, there was no significant increase in the particle size, but more polydisperse Co(en) 3(PMo 12O 40) (+, -) were obtained. In poly(ethylene glycol)(PEG) with an average molecular weight(M W) of 600 g/mol and containing LiClO 4[n(O)/n(Li)=100∶1] as the supporting electrolyte, the conductivity of the composite system increases upon the addition of PMo 12-Co(+ or -) nanoparticles, which was measured by the a.c. impedance technique. The interactions among PEG, LiClO 4, PMo 12, and Co can be used to explain that the PMo 12-Co(+ or -) nanoparticles could promote the conductivity of the PEG-LiClO4-PMo12-Co system.
The title complex, [ [ Cd（Him） （OH-BDC） （H2O）2 ]· 3H2O]n （ 1 ） （Him is imidazole, OH-H2BDC is 5-hydroxyisophthalic acid）, was synthesized by liquid/liquid diffusion method at room temperature. The complex crystallizes in orthorhombic, space group P212121, with a = 0.671 6 （7）, b = 1.380 6 （2）, c = 1.7421（2） nm, V = 1.615 2（3） nm3, C11H18CdN2O10, Mr = 450.67, Dc = 1.853 g/cm3, μ = 1.407 mm^-1, F（000） = 904, Z = 4, the final R1 = 0.020 9 and wR2 = 0.045 3 for 3 211 observed reflections （Ⅰ 〉 2σ （Ⅰ））. In the structure of 1, the OH-BDC ligands exhibiting bis-bidentate coordination mode bridge the adjacent Cd centers to form a one-dimensional helical chain and the second ligand Him acting as terminal ligands are attached to the helical chain. It is notable that a series of complicated hydrogen bonds （e. g., N-H… O, O-H… O） exist in the structure, which link neighboring helices into a three-dimensional supramolecular architeeture. An observed intense blue luminescence with an emission band peaking at 390 nm for 1 may be resulted from ligand-to-metal charge transfer （LMCT）.
