Probing the\nRedox Reactivity of Alkyl Bound Astatine:\nA Study on the Formation and Cleavage of a Stable At–C Bond

The formation of a stable alkyl At–C bond occurs\nduring\nthe shipment of <sup>211</sup>At on a 3-octanone-impregnated column\nand the reactivity of <sup>211</sup>At stripped from columns has been\nstudied. The <sup>211</sup>At could not be recovered from the 3-octanone\norganic phase using nitric acid or sodium hydroxide, even up to 10\nand 15.7 M, respectively. Several reducing and oxidizing agents, including\nhydrazine, hydroxylamine, ascorbic acid, ceric ammonium nitrate, potassium\npermanganate, sodium hypochlorite, and calcium hypochlorite were used\nto promote the recovery of <sup>211</sup>At. The most effective reducing\nagent was hydroxylamine, where ∼70% of the <sup>211</sup>At\nwas recovered, while among oxidizing agents ceric ammonium nitrate,\npotassium permanganate, and sodium hypochlorite all showed near quantitative\nrecovery of <sup>211</sup>At. These results indicate an At–C\nbond is being formed during the shipment of the column and a redox\nreaction is required for bond cleavage to occur. DFT calculations\nhave been used to propose several products of an AtO<sup>+</sup>-3-octanone\nreaction, with 4-astato-5-hydroxy-octa-3-one being the most probable.