EXAFS analyses of technetium(I) and rhenium(I) tricarbonyl complexes - ligand exchange studies.

Tc(I) thioether tricarbonyl complexes were prepared and characterised by chromatographic and spectrometric methods. The complexes undergo various ligand exchange reactions in aqueous solutions. In Tc(I) dithioether tricarbonyl complexes of the formula [Tc(CO)₃Cl(S-S)] (S-S = bidentate dithioether ligand) chlorine is substituted by water in aqueous solution. Moreover, we found that Tc(I) tricarbonyl complexes containing a bidentate dithioether ligand, [Tc(CO)₃Cl(S-S)], as well as a tridentate carboxylato dithioether ligand, [Tc(CO)₃Cl(S-S-O)], react with histidine and form the complex [Tc(CO)₃His]. EXAFS measurements were performed to estimate structural parameters of the dissolved Tc(I) tricarbonyl complexes and their substitution products with water and histidine.