In^III and Ga^III Complexes of Sugar-Substituted Tripodal Trisalicylidene Imines: The First ⁶⁸Ga-Labelled Sugar Derivative

Gallium and indium complexes derived from salicylaldimines of 1,1,1-tris(aminomethyl)ethane (TAME) with pendantxylose, glucose and galactose units have been synthesised as model compounds for potential application as radiotracers. The formed neutral complexes have been characterised by NMR spectroscopy, elemental analysis, mass spectrometry and, in the case of the galactose-bearing In^III complex, by single-crystal X-ray structure analysis. Octahedral coordination was observed with the appearance of an equilibrium of - and -isomers at the metal centre. The glucose-appended ligand was radiolabelled with ⁶⁸Ga^III ions in up to 98 % yield depending on the prevailing pH value. The in vitro stability of the radioactive complex was examined by challenge experiments against apo-transferrin and blood plasma. Very high stability was observed; even after a period of 2 h, 90 % of the complex could still be detected.