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

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 BF4 anion, the remaining BF4 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.