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C2TN
On January the 1st of 2020
this Research Group moved from C2TN
to the "Centro de Química Estrutural", CQE, of IST

PROBING HIGH OXIDATION STATES IN THE LANTHANIDE SERIES

G5 1

 

Lanthanide (Ln) chemistry is dominated by the +3 oxidation state, although some Ln show significant +2 and +4 chemistry. Recently, the synthesis of molecular Pr(V) species, in the gas phase and/or in noble-gas matrices, was reported. We have previously demonstrated that [Ln(NO3)4]- complexes, produced by ESI-QIT-MS, yield [LnO(NO3)3]- species by collision-induced dissociation (CID) after NO2 elimination, and that their relative hydrolysis behavior is related to the stability of the Ln +4 oxidation states. For Ce, Pr and Nd, it was possible to form [LnO2(NO3)2]- ions by subsequent CID of [LnO(NO3)3]-, and these anions revealed different reactivities with water, namely, hydrolysis for Ce, hydration for Nd and no reactivity for Pr. These differences seem to indicate that Pr is in a stable +5 oxidation state, which was confirmed by ab initio computations. Pr(V) is clearly accessible and higher oxidation state lanthanide chemistry could be richer than previously supposed.