Influence of americium complexation on the radiation-induced chemical reactivity of sulfophenyl bistriazinyl pyridine (SO3-Ph-BTP) towards the nitrate radical

A bstract Sulfophenyl bistriazinyl pyridine (SO 3 -Ph-BTP) is a hydrophilic organic ligand used to separate actinides and lanthanides. Dose accumulation and time-resolved studies have previously provided insight into the radiolytic stability and degradation pathways of SO 3 -Ph-BTP in reprocessing environments, but no study has yet addressed the impact of minor actinide complexation on the radiation chemistry of this ligand. To begin to fill this knowledge gap, a systematic, time-resolved study exploring the reactivity of the nitrate radical (NO 3 • ) with SO 3 -Ph-BTP in the presence of trivalent americium, Am(III), has been conducted, which demonstrates enhanced reactivity (an order of magnitude faster) upon metal complexation. • Insights into radiolytic stability of organic ligands in nuclear fuel reprocessing. • Nitrate radical (NO 3 . • ) reactivity with SO 3 -Ph-BTP increases upon complexation with americium. • Protonated SO 3 -Ph-BTP reacts slower with NO 3 . • than the deprotonated form. • Understanding metal-ligand speciation is needed to predict actinide radiation chemistry.