| This Thesis describes the synthesis of novel organoselenium and organotellurium compounds and their evaluation as mimetics of glutathione peroxidase (GPx), the selenoenzyme that protects cells from oxidative stress by reducing harmful peroxides with the thiol glutathione. Novel aromatic derivatives of the previously reported 1,2-oxaselenolane Se-oxide and 1,6-dioxa-5λ4-selena-spiro[4.4]nonane (a spirodioxyselenurane) displayed significantly lower catalytic activity in the reduction of hydrogen peroxide and tert-butyl hydroperoxide with the sacrificial thiol benzyl thiol, compared to their parent compounds. Conversely, aliphatic tellurium analogues proved to be extraordinary GPx mimetics, providing the fastest reaction rates by far of all of the compounds investigated to date in our laboratory. Our study was expanded with the evaluation of the effect of substitution on the catalytic activity of the aromatic cyclic seleninates and spirodioxyselenuranes. In general, electron-donating groups in the para position relative to the selenium atom increased their GPx activity, while catalysts with electron-withdrawing groups proved to be inferior in catalytic activity when compared to the unsubstituted compounds. Additionally, a highly unusual tellurium dimer, containing an ether and a peroxy bridge was discovered along with an unstable spirodiazaselenurane and its acylaminoselenonium salts. |
