Selectivity among, and aggregation of, lanthanide ions

Ligands that show selectivity towards, and aggregation of, lanthanides are of intrinsic interest in coordination chemistry. We have shown that Schiff base and amine phenolate ligands exhibit a variety of coordination modes in lanthanide(III) complexes, and that tren-(tris((2-amino)ethyl)amine)-based amine phenolates show selectivity towards later lanthanide(III) ions. By altering the nature of the amine phenolate ligand backbone the coordination mode of the ligand in solution can be easily controlled. Selectivity among lanthanide(III) ions can be controlled by substitution of the parent ligand donor atoms (phenolate oxygen) with donor atoms of a different type (e.g. phosphinate oxygen). By derivatizing the ligand to include more donor atoms and by stiffening the backbone, it is possible to control the aggregation of lanthanide(III) ions (enabling the formation of dimeric lanthanide complexes).