Synthesis of a Bifunctional Macrocycle
Macrocycles are important organic ligands for encapsulating metal ions. This work describes the first step of a synthesis to create a bifunctional macrocyclic ligand suitable for nuclear magnetic resonance spectroscopy (NMR) studies. Cyclen is an organic macrocycle that contains twelve atoms total, with four nitrogen atoms incorporated into the cyclic backbone. Cyclen can be modified to coordinate a variety of metal ions by adding additional chelating arms. This synthesis is focused on functionalizing three of the donor nitrogens with carboxylate arms, while strategically leaving the fourth nitrogen available for further modification.