BIFUNCTIONAL LIGANDS FOR RATIOMETRIC SENSING OF Cu(II) AND NUCLEAR IMAGING WITH Zr-89: DESIGN, SYNTHESIS, CHARACTERIZATION AND AQUEOUS SPECIATION

Rational ligand designed for complexation of metal ions in solution spans many applications such as catalysis, therapeutic agents, metal ion sensors, imaging and diagnosis of the human body, and others. The key elements to tailoring the right ligand for a particular metal ion is ensuring selectivity over other metal ions and binding with high enough affinity for the intended purpose. The first part of this work focuses on the development, and characterization of a 2,2\u27:6\u27,2\u27\u27-terpyridine-based bifunctional ligand (terpy2). This ligand is intended to act as a receptor for Cu(II) in a fluorescent polymer-based ratiometric sensor for bioavailable Cu(II) in environmental waters. Solid state and solution studies validated the suitability of this ligand as a Cu(II) receptor and showed selectivity over various environmentally relevant metal ions. The second part focuses on the development, and characterization of a 2,9-dimethyl-1,10-phenanthroline based ligand (dmpd-C6) that is aimed to be incorporated in the Cu(II) sensor in order to reduce Zn(II) interference. Density functional theory (DFT) computations and solution studies validate the ligand design and show enhanced selectivity of dmpd-C6 towards Zn(II) relative to Cu(II). Although dmpd-C6 was found to form coordination dimers in solution, this should not be an issue once it is copolymerized with the sensor in a dilute fashion. The third part of this work presents a new octadentate bifunctional ligand for Zr(IV) that is based on the iron overload drug desferrioxamine B (DFO). The ligand (abbreviated DFO-8) is intended to enable radiolabeling of monoclonal antibodies with Zr-89 to allow for extended positron emission tomography (PET) imaging of slow biological processes. DFO-8 was synthesized in an efficient one-step synthetic route and characterized by DFT computations and potentiometric titrations. Aqueous speciation studies demonstrated superior chelation of DFO-8 to Zr(IV) compared to the parent molecule DFO