Synthesis And Properties Of Organic-inorganic Hybrid Materials Based On Vacant Polyoxometalates And Metal Crown Compounds

The rich and interesting structures of polyoxometalates(POMs)as well as their good properties in catalysis,magnetism,optics,electricity,medicine,etc,have attracted many people attentions.Besides it is a hot topic for researchers to study the new compounds which are assembled with POMs produced by in situ reaction and the different metals and organic ligands.But the structures of POMs are affected by many factors in the assembly process,so the directional design of compound is still a big challenge.Up to now,the assembly synthesis of the novel compounds still commit to a single POMs.Few people try to put two or more than two kinds of polyoxometalates(mPOMs)together in the assembly process,which limits the synthesis and assembly of more novel compounds based on POMs.In this paper,we designed and synthesized eight novel compounds based on POMs,and all compounds have been determined by single-crystal X-ray crystallography,powder X-ray diffraction,elemental analysis,thermal analysis,IR-spectra,UV-Vis spectra,high resolution mass spectrometry,electrochemical properties and flurescence spectroscopy.The main contents are as follows:The first,we designed and synthesized three novel compounds by adjusting pH,(H2bpz)6[Co2(P2W16057)2]·22H2O(1)(H2bpz)6[Co3H2(P2W16O57)(P2W15O56)(H2O)]· 12H2O(2)[Na(H2O)6][Co6(pydz)4(PW10O37)2(H2O)6][Co3(OH)(pydz)4(H2O)7]·43H2O(3).The polyoxometalates in three different compounds were produced by in situ reaction.The electrochemical and electrocatalytic properties of 1-3 and their magnetic properties were studied.The second,the dawson type POMs,single molybdate,different organic ligands and metal ions went to self-assembly under hydrothermal conditions,and synthesized five compounds,[Cu6?(2,2'-bipy)6(Mo6O22)(SiW12O40)]n(4);{[Cu6?(ppz)6(H2O)5(MoO4)(SiW12O40)]·4H2O}n(5);{[Cu4?(Hpz)8(SiW12O40)]·2H2O}n(6);?[Co2?(2,2'-bipy)6(SiW11MoO40)]·8H2O?(7);{[Cu2?(2,2-bipy)4(SiW12O4o)]· 2H2O}n(8).Compound 4 contained polyoxotungstates and isopolymolybdate,and compound 5 contained polyoxotungstates and single molybdate.The basic properties were studied,and mass spectra,cyclic voltammetry,electrocatalytic reduction and magnetic properties were also studied.The third,we used different alkali metals to synthesize a series of metal crown compounds.[Na2Cl2Cu?12(pz)12](9);[Na2Br2Cu?12(pz)12](10);[Na2I2Cu?12(pz)12](11);[KCICu?6(pz)6](12);[KBrCu?6(pz)6](13);[KICu?6(pz)6](14);[Cu?6F(OH)2(pz)9(DMF)3(H2O)]· 3DMF(15).Their mass spectra,electrochemical and electrocatalytic properties,as well as electrochemical stability were studied.Meanwhile,the fluorescence properties of the compound 13-15 were also studied.