Syntheses and First Crystal Structures of Rhenium Complexes Derived from ψ-Functionalized Fatty Acids as Model Compounds of Technetium Tracers for Myocardial Metabolism Imaging

Abstract

In an attempt to develop new technetium-based radiopharmaceuticals for the noninvasive diagnosis of myocardial metabolism, we have synthesized three examples of novel metal-containing fatty acid derivatives according to the “3+1” mixed-ligand and the Schiff base/tricarbonyl design. The chelates contain the metal core in the oxidation states +5 and +1, respectively, and are attached to the end-position of a fatty acid chain. The complex formation was accomplished by ligand-exchange reactions with three different rhenium precursors, whereas the inactive rhenium metal was utilized as a surrogate of the technetium radionuclide. The molecular structures of the fatty acid complexes 7, 10 and 14 were determined by single-crystal X-ray diffraction analyses and impressively show a general problem in technetium tracer research, namely the significant structural alterations of bioactive molecules by coordination even to small metal chelates. (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)