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Review of the effects of pH on the synthesis of heteropoly tungstate anions
Sadiq H Wasfi1,W Leo Johnson 3rd1
Chemistry Department, Delaware State University, Dover, Delaware 19901, USA.
DOI: 10.2741/1162 Volume 8 Issue 6, pp.936-944
Published: 01 September 2003

The reaction of the WO4(2-) ion in the pH range 2 to 8 was carried out with the following metal ions individually in combination: Mn2+, Mn3+, Fe2+, Fe3+, Co2+, Co3+, Ni2+, Cu1+, Cu2+, Zn2+, Ga3+, Mg2+, In3+, RAsO3(2-), RSbO3(2-). Some 36 heteropolyanions have been isolated in the crystalline form characterized fully. The antiviral activity of these anions has been determined against HIV, herpes respiratory viruses. The redox potentials for these anions have been measured by cyclic voltammetry documented. At pH 8, the anions adopt a Weakley structure at pH 7, the Keggin structure is formed. At pH 6 to 7, the distorted Keggin structure, 1:1:11, is formed. Below pH 6, the distorted Dawson structure is formed. Some anions showed good antiviral activity with positive redox potentials and others with negative redox potentials. When the metal ion is attached to an organic group, a ring-type structure is formed: a 2:5, 2:6, and 1:7 heteropolytungstate.

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Sadiq H Wasfi, W Leo Johnson 3rd. Review of the effects of pH on the synthesis of heteropoly tungstate anions. Frontiers in Bioscience-Landmark. 2003. 8(6); 936-944.