The Chemistry of Technetium-Water Complexes within, the Manganese Triad: Challenges and Perspectives

The chemistry of technetium is essentially driven by radiopharmaceutical applications. These comprise the syntheses of novel complexes but, moreover, the combination of targeting biomolecules with metal complexes. Aqua ions are especially convenient for facilitatating the introduction of metal cations into biomolecules, but Eire nonexistent for Tc and Re in the Mn triad. This microreview will discuss the chemistry of those Tic complexes that contain H2O as ligands. Special attention will be payed to organometallic aqua ions, i.e. complexes that are typically organometallic with water as ligand. Of particular interest is the coordination chemistry of [M(OH2)(3)(CO)(3)](+) (M = Mn, Tc, Re) complexes in water since it is the origin of the widely applied radiopharmaceutical research with Tc-99m and Re-188. The chemistry of organometallic aqua ions is not confined to Werner-type ligands, hence, a further emphasis will be placed on pure organometallic chemistry in water. ((c) Wiley-VCH Verlag GmbH & Co, KGdA, 69451 Weinheim, Germany, 2009)