Modeling Novel Radiopharmaceuticals:  Mono-C6-Substituted PnAO Ligands (PnAO = 3,3,9,9-Tetramethyl-4,8-diazaundecane-2,10-dione Dioxime)

Abstract

The solid-state behavior of six novel 6-substituted PnAO (propylene amine oxime) complexes (6-11) involving Tc(V), Co(III), and Cu(II) salts is reported. Each of the Tc complexes 6-8 has the C6-substituent located equatorially in a six-membered chelate ring involving a Tc=O unit which has the expected boat geometry. The C6-substituent therefore has little effect on the conformational behavior of the PnAO complex and thus provides an attractive site for further modification. The Co(III) complex 9 has the expected octahedral geometry, while the Cu(II) complexes 10 and 11 form square-based pyramids capped by water molecules. One Cu(II) system (10) contains two unique complexes in the asymmetric unit which are associated via multiple hydrogen bonds to a BF(4) anion, the remaining BF(4) anion being loosely hydrogen bonded to a coordinating water molecule. The cobalt and copper complexes 9-11 each exhibit a chair conformation for the six-membered chelate ring.

Coordinating Radiometals of Copper, Gallium, Indium, Yttrium, and Zirconium for PET and SPECT Imaging of Disease

“…97 Propylenediamine dioxime ligands have also been examined for their Cu(II) complexation in order to model radiopharmaceuticals. 98 The cation was again found to adopt a squarepyramidal coordination geometry featuring an apical water. Dioxotetraazamacrocyclic Cu(II) complexes have been investigated for their radiocopper chelation potential.…”

“…Monocationic diimine dioxime ( L32 ) complexes of Cu(II) were labeled with 64 Cu, and their biodistributions were studied. − The X-ray structure of a Cu(II) complex of a pyridyl-tethered derivative revealed a tetradentate ligand ( L33 ) forming the base of a square pyramid with an axial water but no pyridyl coordination (Figure ) . Propylenediamine dioxime ligands have also been examined for their Cu(II) complexation in order to model radiopharmaceuticals . The cation was again found to adopt a square-pyramidal coordination geometry featuring an apical water.…”

Single-Crystal-Structure Directed Predesign of Cationic Covalent Organic Polymers for Rapidly Capturing 99TcO4–

“…Besides, intense C–H···O hydrogen bonds can also be observed between the bipyridinium ligand and ReO 4 – / 99 TcO 4 – (Figures b and S8e,f). After all the bromide and water molecules were replaced by ReO 4 – and 99 TcO 4 – , Py2@Re and Py2@Tc have formed in the space group of P 2 1 (Figure S9). The asymmetric units of both metal–organic complexes contain one Py2 molecule and two oxyanions (Figure S9a,b).…”

“…Besides, intense C−H•••O hydrogen bonds can also be observed between the bipyridinium ligand and ReO 4 − / 99 TcO 4 − (Figures 1b and S8e,f). 22 After all the bromide and water molecules were replaced by ReO with large size and low electric charge density tend to be hydrophobic, 7,23 which may better match with the local hydrophobic space consisting of methylene groups and aromatic rings. This means that hydrophobic interaction plays a key role in the assembly of the pyridinium compounds and the oxyanions, explaining why all the water molecules have been replaced.…”