High-Yield Preparation of Novel Class of Tc-99m Nitrido Asymmetrical Heterocomplexes

A series of nitrido technetium-99m asymmetrical heterocomplexes, comprising two different bidentate chelating ligands have been prepared at tracer level. These complexes are cmposed by a Tc?N group bound to a diphosphine ligand and to a mono- or dianionic bidentate ligand in a five-coordinate arrangement. The underlying approach to the design of this class of asymmetrical complexes was based on a molecular switch between aquare pyramidal and trigonal bipyramidal geometries determined by the specific set of donor atoms coordinated to the metal center. The high - yield preparation of the complexes have been obtained in high yield and irrespective of the stoichiometric ratio between the two different chelating ligands.