This Perspective provides an overview of the recent progress in the field of bioresponsive MRI probes, highlighting the richness in research approaches and achievements in the visualisation and assessment of important biological markers.
Two symmetric ligands harbouring two TEMPO radicals and two functionalized acetamide arms (R = OMe (L1), CF3 (L2)) were prepared and chelated to lanthanide ions (EuIII, YbIII for both L1 and L2, DyIII for L1).
Five Co(II) complexes with amide or hydroxypropyl groups are studied as paramagnetic chemical exchange saturation transfer agents for MRI. The most promising complexes have cis-coordinated amide pendants in a 14-membered tetraazamacrocycle.
The article highlights a paraCEST study on Co(II) and Ni(II) complexes of a pyridine-tetraacetamide-based ligand. All the required solid and solution state studies of the ligand and complexes have been performed and meticulously discussed.
Solution state studies of structurally characterized stable and inert Co(II) and Ni(II) complexes of tri-pyridine-containing ligands with alcohol and amide pendant arms show potential ParaCEST Contrast behaviour.