Synthesis, crystal structure and chemical stability of bismuth(III) complexed with 1,4,7,10tetraazacyclododecane-1,4,7,10-tetramethylene phosphonic acid (H8DOTMP)

The potential use of the -particle emitting compounds 212/213Bi–DOTMP and 212Pb–DOTMP in therapy of bone-associated cancers, and medical interest in bismuth compounds, motivated this study. Syntheses of the Bi (III) and Pb(II) complexes of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetramethylene phosphonic acid (H8DOTMP) are reported. Extensive pH-stability was found for both complexes, in the pH range 0–13 for Bi–DOTMP and pH 4–14 for Pb–DOTMP. Furthermore, both complexes formed within 1 min in the pH range 6–10 at 10 mu M metal-ion and 15 mu M DOTMP. Single crystals of [NaBi(H4DOTMP)] and polycrystalline [Bi (H5O2)(H4DOTMP)] were formed and characterized by single crystal and powder X-ray diffraction methods, respectively. The structure of the anion was found in both salts to exhibit a square antiprismatic eightcoordination with a four-fold axis of symmetry.