Here we report the formation of the first examples of dicopper(III) bis(μ-oxo) complexes ligated by the primary amines, propylenediamine, and N,N,-dimethyl propylenediamine. Stabilization of these new compounds is effected at -125 °C by "core capture"- introduction of exogenous ligand to a preformed dicopper(III) bis(μ-oxo) complex supported by the peralkylated tetramethyl propylenediamine. Primary amine ligation in these compounds matches the single primary amine coordination of the putative active site of particulate methane monooxygenase (pMMO) and polysaccharide monooxygenase. Reactivity studies presented here show primary amine ligated cores are competent oxidants, capable of activating C-H bonds by an H-atom abstraction mechanism. Trends in spectroscopy, structure, and reactivity provide hints to the potential role of primary amine ligation in pMMO: increased substrate accessibility to the redox active orbitals of the Cu2O2 core and greater stabilization of the oxidant without attenuation of oxidizing power.

Extraction of trace pertechnetate ( 99m TcO 4 − ) from aqueous media using hydrophobic deep eutectic solvents (DESs) is reported for the first time. The hydrophobic DESs studied comprise a 1:2 molar ratio of a tetraalkylammonium or tetraalkylphosphonium halide mixed with a monocarboxylic acid (i.e., saturated fatty acid). Quantitative (>99%) removal of tracer levels of 99m TcO 4− from an aqueous phase in the presence of a large excess of competing anions (e.g., Cl − , NO 3 − , HCO 3 − , H 2 PO 4 − , SO 4 2− ) within 5−60 min at 25 °C without the aid of a formal extracting agent (e.g., ionophore) demonstrates an efficient and selective extraction. At infinite dilution of pertechnetate, very high distribution ratios in excess of 10 3 are observed. Attempts to strip technetium from the DES extractant phase by reduction with SnCl 2 are also reported. Overall, these outcomes provide the basis for considering hydrophobic DESs as an alternative platform for 99 TcO 4 − waste management.

Introduction: [ 227 Th]Th-3,2-HOPO-MSLN-mAb, a mesothelin (MSLN)-targeted thorium-227 therapeutic conjugate, is currently in phase I clinical trial; however, direct PET imaging using this conjugate is technically challenging. Thus, using the same MSLN antibody, we synthesized 3,2-HOPO and deferoxamine (DFO)-based zirconium-89 antibody conjugates, [ 89 Zr]Zr-3,2-HOPO-MSLN-mAb and [ 89 Zr]Zr-DFO-MSLN-mAb, respectively, and compared them in vitro and in vivo. Methods: [ 89 Zr]Zr-3,2-HOPO-MSLN-mAb and [ 89 Zr]Zr-DFO-MSLN-mAb were evaluated in vitro to determine binding affinity and immunoreactivity in HT29-MSLN and PDX (NCI-Meso16, NCI-Meso21) cells. For both the zirconium-89 conjugates, in vivo studies (biodistribution/imaging) were performed at days 1, 3, and 6, from which tissue uptake was determined.Results: Both the conjugates demonstrated a low nanomolar binding affinity for MSLN and >95% immunoreactivity. In all the three tumor types, biodistribution of [ 89 Zr]Zr-DFO-MSLN-mAb resulted in higher tumor uptake(15.88-28-33%ID/g) at all time points compared with [ 89 Zr]Zr-3,2-HOPO-MSLN-mAb(7-13.07%ID/g).[ 89 Zr]Zr-3,2-HOPO-MSLN-mAb femur uptake was always higher than [ 89 Zr]Zr-DFO-MSLN-mAb, and imaging results concurred with the biodistribution studies. Conclusions: Even though the conjugates exhibited a high binding affinity for MSLN, [ 89 Zr]Zr-DFO-MSLN-mAb showed a higher tumor and lower femur uptake than [ 89 Zr]Zr-3,2-HOPO-MSLN-mAb. Nevertheless, [ 89 Zr]Zr-3,2-HOPO-MSLN-mAb could be used to study organ distribution and lesion uptake with the caveat of detecting MSLN-positive bone lesions. Clinical trial (NCT03507452).

The chemistry and radiochemistry of high specific activity radioisotopes of arsenic, rhenium and rhodium are reviewed with emphasis on University of Missouri activities over the past several decades, and includes recent results. The nuclear facilities at the University of Missouri (10 MW research reactor and 16.5 MeV GE PETtrace cyclotron) allow research and development into novel theranostic radionuclides. The production, separation, enriched target recovery, radiochemistry, and chelation chemistry of As,Re and Rh are discussed.