The Synthesis And Properties Of Several New Materials Of The Polyoxometalates Charge Transfer Compound

In recent years, the polyoxometalates acting as electron acceptor and the organic compoundacting as electron donors can form a new charge transfer compound. It’s the reason why thehaving good electrical conductivity, magnetic and optical properties materials is becoming a hotspot of research. It may become a new type of the functional materials. But till now, the researchabout polyoxometalates charge transfer compounds is not very common. So we need find ansuitable organic electron donors from a number of organic compounds, especially from a bigconjugate aromatic organic compounds to synthesis an new charge transfer compound withparticular physical and chemical properties.This article chooses rhodamine B, p-aminoazobenzene or1,10-phenanthroline as electrondonors and Keggin polypxpmetalates or sandwich polyoxometalates as the electron acceptors. Bydouble decomposition reaction we had reported the never seen six new organic-polymetallicoxygen charge transfer compounds. Including:(1) using rhodamine B,12-molybdenumphosphate,12-molybdenum germanium acid and12–molybdenum silicon acid, we synthesisthree kinds charge transfer compound;(2)using p-aminoazobenzene,12-tungsten molybdenumand12-tungsten phosphoric acid, we synthesis two kinds charge transfer compounds;(3) using1,10-phenanthroline and sandwich type1:9tungsten series K10P2W18Co4(H2O)2O68·20H2O aselectron acceptor, we synthesis a new charge transfer compound. By C, H, N elements analysisand thermogravimetric analysis eventually determine the formula of the six kinds of chargetransfer compounds, respectively.[(C28H35N2O3)4H]SiMo12O40·11H2O (1)[(C28H34N2O3)3H]PMo12O40·8H2O (2)[(C28H35N2O3)4H]GeMo12O40·10H2O (3)[(C12H12N3)3H]PW12O40·8H2O (4)[(C12H12N3)3H]PMo12O40·9H2O (5)[Fe(C12H8N2)3]10[P2W18Co4(H2O)2O68]3·10H2O (6)Analysing the infrared spectra and ultraviolet visible spectrum diagram of the charge transfercompounds shows that there are organic molecule and the polyoxometalates’ peak. That is to saythe polyoxometalates anion’ skeleton has not changed, but the peak position and intensity havechanged differently. By solid diffuse electron spectroscopy we reveals that the new peak withinthe scope of visible light (380-780nm) is showing that the organic conjugate electrons hadtransferred to the polyoxometalates anions making W(V)â†'W(VI) or Mo(V)â†'Mo(VI). Bycalculating the band gap of the charge transfer compounds, we knew that the band gap value ofthe charge transfer compounds is smaller than single polyoxometalates’ band gap values, whose nature is closer to the semiconductor. Using cyclic voltammetry to study the electrochemicalproperties of charge transfer compounds showed that the new charge transfer compound remainedgood redox properties of the polyoxometalates. Through the magnetic test, it showed that the newcharge transfer compounds are having obvious paramagnetic absorption due to single electron.