Hydrothermal Synthesis And Crystal Structure Characterization Of Polyoxometalates Compounds

Due to it's rich structure types and special functions, Polyoxometalates have potential and extensive application in catalysis, biology, medicine, thin film material, electrician and magnetics etc.. The design and synthesis of metal oxide heterpoly compound will accelerate the develop of chemistry and other research areas related.In this research, two novel molybdophosphates {[Cu(phen)2][Cu(phen)(OH2)]2 [P2MO5O23]}9H2O, (H3dien)2P2Mo5O23 and two novel tungstophosphates [Cu(2,2-bipy)(OH2)2] [Cu(2,2-bipy)]2(PO4)(P2W18O62)0.5 2H2O, and (enH2)5 (HP2W18O62)2 22H2O organic-inorganic hybrid compounds were hydrothermally synthesized respectively by modifying synthetic conditions and using simple starting materials and organic amines as templates. The structures and properties of these composites were determined by single crystal X-ray diffraction, ICP, CHN, IR and TG-DTA. The influencing factors on Mo-P and W-P framework of hybrid compound were also studied prelimimarily.It was found that both the pH value and starting material quotas of the reaction system affect the final production greatly. The species of the second metal and the species of the organic templates are two key factors for the production. Different organic amines can result in different structure.The results showed that {[Cu(phen)2][Cu(phen)(OH2)]2[P2Mo5O23]}-9H2O and (H3dien)2P2Mo5O23 have the same Strandberg molybdophosphate heteropolyanions structure as that of the mail inorganic structure. The Strandberg type heteropolyanions [P2M5O23]6- was composed of five MoO6 octahedra and two PO4 tetrahedrons, which showed a distorted pentagonal bi-pyramidal configuration, and bonded to the second metal amidocyanogen copper cation. The compound was a polyoxometalates-organic hybrid material with samdwich structure through π-π stacking interactions between phen groups. The compound (H3dien)2P2Mo5O23 showed an infinite planar structure by hydrogen bonds between polyanion [P2Mo5O23]6- and protonated [dienH3]3+. The protonated dien occupied the interlayer of the framework and balanced the charge of the framework.The compound [Cu(2,2-bipy)(OH2)2][Cu(2,2-bipy)]2(P04)(P2W18O62)0.5 2H2O was polyoxometalate-organic hybrid material based on Dawson type heteropolyanions. It indicated an unprecedented straight channels formed by three different copper-amine cationic units through W(1)-O(2)-Cu(1)-O(32)-P(2)-O(34)-Cu(1A)-O(1A)-W(1A) chain. In the inorganic-organic hybrid materials (enH2)5(HP2W18O62)2 22H2O, the heteropoly anions and protonated enH22+ were built into a double parallel chains by hydrogen bonds. The adjacent chains formed a 2D planar structure by N-H.. .O hydrogen bonds.