Prostate cancer is one of the most widespread types of cancer in men and at the forth position of common cancer types in 2018 according to the World Health Organization report of 2020. The prostate-specific membrane antigen (PSMA) is highly expressed on prostate cancer cells and it is the important target for imaging and therapy of prostate cancer. In spite of the considerable progress in the improvement of existing tracers and the development of novel tracers for positron emission tomography (PET), the single-photon emission computed tomography (SPECT) with its workhorse 99mTc remains the dominating technique in diagnostic nuclear medicine. The fundament for labelling reactions with 99mTc is an exact knowledge of the coordination chemistry of the radioactive transition metal. The related structural studies are commonly done with the longlived isotope 99Tc, a weak β- emitter. This is a survey of the coordination capabilities of (η5-cyclopentadienyl)tris(dimethyl phosphito-P)cobaltate(III), {LOMe}−, the so-called Kläui ligand, to technetium with consideration of all common oxidation states of this transition metal and moreover, to further important metalions for medical approaches. The coordination chemistry of different thiourea ligands with rhenium and technetium are explored as well. The background of this work is the quest for stable metal cores for ongoing nuclear medical labeling experiments.
