الفهرس 
AcknowledgementOnly 14 pages are availabe for public view
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Abstract
In this work, we synthesized five cluster compounds involving the decavanadate polyoxoanion. The decavanadates, in general, allow for structural diversity based on various charming types of {VOx} polyhedra (x=4-6) and find great utilization in biological processes, medicine and energy conversion and storage applications. In details, this thesis comprises preparing and studying the antibacterial compounds of decavanadate cluster compounds containing Mg(II), Co(II), Ni(II) and Hg(II). A brief description of the different chapters in this thesis is given as follows:
• The first chapter contains a general literature survey on the meanings, crystal structures and applications of the polyoxometalates and polyoxovanadates. It shows in details examples of cluster compounds exhibiting different polyoxoanionic types of the vanadate anion (VO3)-. These cluster compounds included bivanadate anion {Cu3V2O7(OH)2·2H2O}, trivanadate anion {[(C4H9)4N]3(V3O9)}, tetravanadate anion {Cu2V4O16}, pentavanadate anion {(NH2Me2)12[(V5O9Cl)6(L)12]}, hexavanadate anion {[(C2H5)4N]4[PdV6O18]}, heptavanadate anion {(NH4)2V7O16}, octavanadate anion {[(C2H5)4N]4[Cu2V8O24]}, nonavanadate anion {TBA4[HTeV9O28].2CH3CN} and decavanadate anions {with a main element Ba3[V10O28].19H2O, a transition element (NH4)2[Ni(H2O)5(NH3)]2[V10O28]·4H2O and an inner transition element [Ho(H2O)8]2[V10O28].8H2O}.
• The second chapter includes the experimental details of preparing the cluster compounds along with description of the various analytical techniques and instuments used for studying the cluster compounds.
• The third chapter contains the results and discussion of the crystal strutures, infrared spectra and thermal analyses of the cluster compounds. These results can be summarized as follows:
o The formation of two polymorphs of (NH4)2[Mg(H2O)6]2V10O28∙4H2O {a bis(hexaaquamagnesium(II)) complex-decavanadate cluster compound} stabilized via a three-dimensional network of hydrogen bonds was controlled by the addition of different organic molecules to the reaction medium. The two polymorphs {monoclinic (C2/c) and triclinic (P-1)} were characterized by single-crystal XRD analysis, elemental analysis and FT-IR spectroscopy. Additionally, their thermal decomposition mechanisms to a composite product of V2O5 and Mg(VO3)2 were elucidated. The antibacterial activities and the minimum inhibitory concentrations by the polymorphs were revealed against two human pathogenic bacterial strains (E. coli and P. aeruginosa) and a phytopathogenic bacterial strain (R. solanacearum). The inhibitory activity and the minimum inhibitory concentration values of the tested cluster compounds showed pronounced higher antibacterial activities of the triclinic polymorph against E. coli and P. aeruginosa, while the monoclinic polymorph afforded higher inhibitory activity against R. solanacearum with minimum ihibitory concentration value of 1.125 mg/ml. Interestingly, the inhibitions against R. solanacearum given by the polymorphs are comparable to that obtained by streptomycin ”the antibacterial standard”.