The Cyclotron Production and Cyclometalation Chemistry of 192-Ir

The goal of this thesis is to demonstrate the cyclotron production, radiochemical isolation, and cyclometalate chemistry of radio-iridium isotopes. In recent work, Luminescence Cell Imaging (LCI) has been combined with radioisotopes leading to compounds that can be imaged with both optical microscopy and nuclear techniques. Radiometals excel in this multifunctional setting, providing ideal chemical and nuclear properties for luminescence, biological targeting, nuclear diagnostics, and therapy. Iridium cyclometalate compounds have demonstrated potential in LCI with excellent photophysical properties. Independently, low specific activity 192-Ir has been successfully applied in brachytherapy as a high-intensity beta (-) emitter. Despite this, radio-iridium has not been applied to cyclometalate chemistry, nor a radiochemical isolation method developed for its cyclotron production. Herein is demonstrated the feasibility of the production and isolation of radio-iridium, and its application to cyclometalate chemistry as a potential tool for nuclear medicine research. Natural osmium was electroplated onto a silver disc from basic media, and the thin deposits obtained were weighed and characterized with scanning electron microscopy. These targets were irradiated using the TRIUMF TR13 cyclotron, delivering 12.7 MeV protons to the target disc to access the A-Os(p,n)A-Ir reaction channels. Three irradiations were performed at 5 microamps for 1 hour, and one at 20 microamps for 2 hours. Gamma spectra of the targets were collected and the range of iridium isotopes (186-190, 192) identified and quantified. The irradiated material was then oxidized, dissolved from the target backing, and separated via anion exchange. Once isolated, the isotopes were applied to an adapted cyclometalation procedure, and the compounds were identified and quantified against non-radioactive standards using high performance liquid chromatography with coupled gamma-ray and ultraviolet detectors. The procedure developed here has enabled the study of radio-iridium cyclometalates, a potentially new class of theranostic compounds for nuclear medicine.