The Structural Characterization of Amavadin

Abstract

Fly agaric accumulate vanadium in the form of amavadin, whose structure has been elucidated (see picture for the crystal structure). Amavadin contains one V^IV center coordinated to two (S,S)-hidpa^3- ligands (H₃ hidpa=2,2'-(hydroxyimino)dipropionic acid) through one η² -NO^- group and two unidentate carboxylato groups from each ligand. The arrangement of the two η² -NO^- groups leads to a chiral vanadium center, which has been characterized in both the Λ and Δ forms. The carboxylato groups of the amavadin anions bind cations, for example, Ca²⁺ ions, and/or become involved in hydrogen bonding.