Active cytotoxic reagents based on non-metallocene non-diketonato well-defined C₂-symmetrical titanium complexes of tetradentate bis(phenolato) ligands

A new family of non-Cp-based non-diketonato-based C₂-symmetrical octahedral Ti(IV) complexes of dianionic diamine bis(phenolato) ligands, which are conveniently obtained as single isomers in quantitative yields, leads to appreciable cytotoxicity against colon and ovarian cells with a non-transferrin-dependent cell penetration mechanism. The ligand structural features including steric demands, symmetry, and aromaticity strongly influence activity, supporting its role in the biological mechanism of action.