Synthesis and stability of the [Ti]Ti-DOTA complex: en route towards aza-macrocyclic Ti-based radiopharmaceuticals.

We report the use of DOTA as a chelator for titanium. The resulting complex is fully characterised and stability studies reveal its high kinetic inertness against transmetallation and transchelation. The radiolabeling of DOTA with Ti, a guaiacol-based liquid-liquid extraction method, leads to a high radiochemical conversion up to 98%.