The Structural Characterization of Amavadin

Fly agaric accumulate vanadium in the form of amavadin, whose structure has been elucidated (see picture for the crystal structure). Amavadin contains one VIV center coordinated to two (S,S)‐hidpa3− ligands (H3hidpa=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.