Synthesis and characterization of polyoxometalates for novel anti-viral (HIV-1) therapies and selective catalytic oxidations of alkenes

This dissertation investigates a specific class of polyoxotungstates, the polytungstophosphates of formula A- and B-{dollar}rm PWsb9Osb{lcub}34{rcub}sp{lcub}9-{rcub},{dollar} under physiological conditions. It is demonstrated that both isomers equilibrate rapidly to generate the same distribution of products and that this distribution depends principally on the buffer used. Polytungstophosphate product distributions were evaluated in both aqueous and non-aqueous solution by {dollar}sp{lcub}31{rcub}{dollar}P NMR. The previously unappreciated complexities in the chemistry of these compounds under neutral aqueous conditions indicates that evaluation of these compounds in cell culture and in other biological screens must be done with care. The anti-HIV-1 activity and toxicity of representative structural families of polyoxotungstates in human lymphocytes are also described.; The synthesis and characterization of new cesium and tetramethylammonium salts of polyoxotungstate anions with covalently attached organosilyl groups is also discussed. All these organosilyl polyoxotungstates are stable in aqueous media over a period of several hours as assessed by {dollar}sp1{dollar}H NMR. High resolution NMR studies ({dollar}sp1{dollar}H, {dollar}sp{lcub}183{rcub}{dollar}W, and {dollar}sp{lcub}29{rcub}{dollar}Si) established for the first time the stereochemistry of attachment of organosilyl groups to the polytungstosilicates in this large class of compounds. The anti-HIV-1 activity of these compounds was evaluated and the results for four are presented.; Finally, results from the oxidation of cyclohexene, styrene, and 1-octene by hypochlorite catalyzed by a variety of TMSP complexes are presented. These two-phase oxidations were conducted in two modes, one with quaternary ammonium salts of the TMSP catalysts dissolved in the organic phase and the other with the alkali metal salts of the catalysts dissolved in water. Ketones, enols, enones, and eventually some carbon-carbon double bond oxidative cleavage products are also observed. The quantity of chlorinated products that are generated in these reactions varies greatly with the conditions and is substantial in some reactions. These oxidations are of importance as they represent an improvement over other homogeneous olefin epoxidation systems catalyzed by Ni complexes. Significantly, they represent the only TMSP catalyzed oxidation processes compatible with basic conditions. Time dependence of the distribution of organic products and kinetics data indicate these processes likely involve freely diffusing radical intermediates and are very complex.; The appendix summarizes efforts to catalyze the transfer of six-electron nitrene and carbene equivalents to olefin substrates. (Abstract shortened by UMI.)...