Five novel vanadium substituted series of Dawson-type heteropoly acid H7[As2Mo 17VO 62]·10H2O（l）,H8[As2Mo 16V2O 62]·7H2O（2）, H9[As2Mo 15V3O 62]·8H2O（3）,H8[As2Mo 14V4O 62H2]·7H2O（4）, H9[As2Mo 13V5O 62H2]·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 （ 51V 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.
Three new Keggin polyoxometalates, [Zn(phen) 3 ] 2 [SiW 12 O 40 ]·5H 2 O(1), [Co(phen) 3 ] 2 [SiW 12 O 40 ](2) and [Ni(phen) 3 ] 2 [SiW 12 O 40 ]·2H 2 O(3)(phen=1,10′-phenanthroline) have been hydrothermally synthesized and characterized by elemental analysis, IR, crystal X-ray diffraction, thermogravimetric analyses(TGA) and fluorescence techniques. Complex 1, crystallized in the triclinic space group P1, consists of one [SiW 12 O 40 ] 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=1.742 1(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 architecture. 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).
