Four new vanadium substituted Dawson-type heteropoly acids H7[P2Mo17VO62]·39H2O（1）, H8[P2Mo16V2O62]·41H2O（2）, H9[P2Mo15V3O62]·51H2O（3） and H8[P2Mo14V4O62H2]·45H2O（4） were prepared respec-tively. Their structures were determined by IR and ICP. The inhibition effects of vanadium substituted Dawson-type heteropoly acids（Mo, P） on free radical polymerization of methyl methacrylate（MMA） were investigated by dilatometry. The results show that the rate of the polymerization of MMA decreases and the inhibition effects of the four heteropoly acids reach the inhibitor performance of hydroquinone at a certain ratio.
Three new gallium complexes formulated as [Ga（PDA）2 ][Ga（H2O）（PDA）（phen）]·4H2O（1）,[Ga（PDA） 2]·（H2IN）·2H2O（2） and [Ga（OH）（PDA）（H2O）] 2（3）（H2PDA=pyridine-2,6-dicarboxylic acid;phen=1,10-phenanthroline;HIN=isonicotinic acid） have been synthesized under hydrothermal conditions.In the mixed-ligand system of complex 1,PDA2 and phen are connected to the central Ga 3＋ cation as tri-and bi-dentate ligands,respectively.In complex 2,each Ga 3＋ cation is six-coordinated by two PDA 2 anions octahedrally.Complex 3 shows a binuclear structure,with the bond distance of Ga1― Ga2 being 0.30061（3） nm.The 3D supramolecular structures of the three complexes are constructed via hydrogen bonds and aromatic π-π packing interactions.All the three complexes exhibit intense blue emission at room temperature in the solid state,which are attributed to π＊-π transition centered on the ligands.
