Re(CO)3 complexes synthesized via an improved preparation of aqueous fac-[Re(CO)3(H2O)3]+ as an aid in assessing (super 99m)Tc imaging agents. Structural characterization and solution behavior of complexes with thioether-bearing amino acids as tridentate ligands

Re(CO)3 complexes with tridentately coordinated alpha-amino acids bearing a thioether group is synthesized by using a new strategy for preparing solution of the fac-[Re(CO)3(H2O)3]+ precursor analogues to the solutions for preparing (super 99m)Tc radiopharmaceuticals. The latter generates an asymmetric center, and NMR and X-ray methods provided evidence for the formation of both possible diastereoisomers, which interchange rapidly in solution except when the thioether has an appended acetate group.