Abstract Despite its prevalence in the environment, the chemistry of the Ti 4+ ion has long been relegated to organic solutions or hydrolyzed TiO 2 polymorphs. A knowledge gap in stabilizing molecular Ti 4+ species in aqueous environments has prevented the use of this ion for various applications such as radioimaging, design of water‐compatible metal–organic frameworks (MOFs), and aqueous‐phase catalysis applications. Herein, we show a thorough thermodynamic screening of bidentate chelators with Ti 4+ in aqueous solution, as well as computational and structural analyses of key compounds. In addition, the hexadentate analogues of catechol (benzene‐1,2‐diol) and deferiprone (3‐hydroxy‐1,2‐dimethyl‐4(1 H )‐pyridone), TREN‐CAM and THP Me respectively, were assessed for chelation of the 45 Ti isotope ( t 1/2 =3.08 h, β + =85 %, E β+ =439 keV) towards positron emission tomography (PET) imaging applications. Both were found to have excellent capacity for kit‐formulation, and [ 45 Ti]Ti‐TREN‐CAM was found to have remarkable stability in vivo.
