| The purpose of this dissertation was to study the basic chemistry of some technetium(V) and rhenium(V) compounds as well as the biodistributions of the novel {dollar}sp{lcub}rm 99m{rcub}{dollar}Tc(V) compounds.; New classes of tetradentate-N{dollar}sb2{dollar}S{dollar}sb2{dollar} and tetradentate-N{dollar}sb4{dollar} ligands which contain 5,7,5-membered ring chelate system have been used in this study. The presence of the 7-membered chelate ring provides synthetic flexibility for the attachment of different side-chain substituents, and thus for a ready route to control the biodistribution of the resulting {dollar}sp{lcub}rm 99m{rcub}{dollar}Tc radiopharmaceutical.; The labelling of the new ligands with {dollar}sp{lcub}rm 99m{rcub}{dollar}Tc results in a single radiochemical product, or the expected stereoisomeric products. Analytical data indicate that all the novel N{dollar}sb2{dollar}S{dollar}sb2{dollar} and N{dollar}sb4{dollar} ligands form a tetradentate 5,7,5-membered ring chelate system with mono-oxo Tc(V) or Re(V) core: (M(V)OL) {dollar}sp{lcub}rm x{rcub}{dollar} (M = Tc(V) or Re(V); L = tetradentate N{dollar}sb2{dollar}S{dollar}sb2{dollar} or N{dollar}sb4{dollar} ligands; x = 0 or {dollar}-{dollar}1).; The inert "yl" oxygen undergoes slow oxygen exchange with free water in alkaline solution. The stoichiometry of the five-coordinate complexes (ReO(DADS)) {dollar}sp-{dollar}, (ReO(DBDS)) {dollar}sp-{dollar} and (TcO(DBDS)) {dollar}sp-{dollar} plus the observed rate law imply an associative mechanism.; In rat biodistribution studies, the DBDS and DADS complexes show very similar biological activity with rapid blood and renal clearance. Phenyl substituents on the 7-membered ring give rise to {dollar}sp{lcub}rm 99m{rcub}{dollar}Tc complexes of increased lipophilicity, increased liver uptake, and minimal hepatobiliary clearance. (Tc(V)ON{dollar}sb4{dollar}) {dollar}sp0{dollar} complexes with phenyl substituents on the 7-membered ring exhibit limited brain uptake. |
