Unusual redox stability of neptunium in the ionic liquid [Hbet][Tf2N]

Abstract

The behavior of neptunium in the ionic liquid betaine bistriflimide, [Hbet][Tf₂N], has been studied spectroscopically at room temperature and 60 °C for the first time. An unprecedented complex redox chemistry is observed, with up to three oxidation states (IV, V and VI) and up to six Np species existing simultaneously. Both redox reactions and coordination of betaine are observed for Np(IV), (V) and (VI). Elevating the temperature accelerates the coordination of Np(V) with betaine and reduction reactions slow down.