Synthesis,Structures And Characteractions Of The Polyoxovanadates

Polyoxovanadates have attracted many interests because of not only its multiple structural units, but also potential application in catalysis, biochemistry and advanced functional materials.In this thesis, on the basis of documental summaries, we obtained ten polyoxo--vanadates through hydrothermal reaction, studied the relationship of structures to spectroscopy.1. Ten novel polyoxovanadates were synthetized, x-ray single crystal diffractometor was carried to determine structures further. Compounds can be clarified to two types according to the polyanions:(1) Compounds 1-3 are isopolyoxovanadates; (2) Compounds 4-10 are heteropolyoxovanadates, of which, compound 4 is vanadium tellurite, and compounds 5-10 are antimony vanadates. Compound 1 is ID, compound 4 is 2D framework, compound 2,3,5-10 are isolated. The cluster unit in compound 3 is isomerized to reported. Protonated organic amine molecules or ammino-type transition metal cations as counter cations formed H-bonds with O atoms from clusters leading to supermolecules.2. Topology analysis are introduced to analysis networks of compounds to profound reasch. The uninodal topology type of compound 1,3 and 8 is not reported. The topology type of compound 2 and 10 is hex hexagonal primitive. The uninodal topology type of compound 4 is ild. The uninodal topology type of compound 5 and 6 is fcu/cubic closest packing. The uninodal topology types of compound 7 and 9 are bet and gpu/gamma Pu, respectively. The binodal topology type of compound 3 is alb. The 3-nodal topology type of compound 6 is not reported, yet.3. We also carried out 2D-IR correlation spectra, UV-DRS spectra, x-ray photoelectr--onspectroscopy and thermo-infrared analysis to characterize compounds. The thermal-perturbation 2D correlation IR spectra show the skeleton responses of polyanions, weak interactions and aromatic rings; the LMCT of 0â†'V, dâ†'d of transition metal and Ï€â†'Ï€* transitions of aromatic rings are also found in UV-DRS spectra; TGA curves indicate that the polyanions are stable below 350℃; thermo-infrared analysis indicate that micromolecules weight loss sequence are free water molecules> free organic amine> chelate organic amine> polyanions, which is excellently fit the result of TGA analysis; the XPS analysis demonstrates that the V and Co is+2 in compound 9,which is perfect identical with BVS calculation.4. We also employed Gaussian 03 program to calculate the polyanions of compounds 2,5 and 9, to earning the single point energy, frontier orbital energy and Mulliken chargesof polyanions. In further, to research the relationship between microstructure and macroscopic properties.