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Amavadin is a 
The ligand found in amavadin was first synthesized in 1954. Amavadin contains vanadium(IV). Initially, amavadin was thought to have a vanadyl, VO2+, center. In 1993, it was discovered by crystallographic characterization that amavadin is not a
vanadium
Vanadium is a chemical element with the symbol V and atomic number 23. It is a hard, silvery-grey, malleable transition metal. The elemental metal is rarely found in nature, but once isolated artificially, the formation of an oxide layer ( pas ...
-containing anion
An ion () is an atom or molecule with a net electrical charge.
The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by convent ...
found in three species of poisonous ''Amanita
The genus ''Amanita'' contains about 600 species of agarics, including some of the most toxic known mushrooms found worldwide, as well as some well-regarded edible species. This genus is responsible for approximately 95% of the fatalities result ...
'' mushrooms: '' A. muscaria'', ''A. regalis'', and ''A. velatipes''. Amavadin was first isolated and identified in 1972 by Kneifel and Bayer. This anion, which appears as a blue solution, is an eight-coordinate vanadium complex
Complex commonly refers to:
* Complexity, the behaviour of a system whose components interact in multiple ways so possible interactions are difficult to describe
** Complex system, a system composed of many components which may interact with each ...
. A Ca2+ cation is often used to crystallize amavadin to obtain a good quality X-ray diffraction. Oxidized amavadin can be isolated as its PPh4+ salt. The oxidized form contains vanadium(V), which can be used to obtain an NMR spectrum.
Preparation
The formation of amavadin begins with the formation of two tetradentateligand
In coordination chemistry, a ligand is an ion or molecule (functional group) that binds to a central metal atom to form a coordination complex. The bonding with the metal generally involves formal donation of one or more of the ligand's electr ...
s.
:2 HON(CH(CH3)CO2H)2 + VO2+ → 2sup>2− + H2O + 4 H+
Structure and properties
The ligand found in amavadin was first synthesized in 1954. Amavadin contains vanadium(IV). Initially, amavadin was thought to have a vanadyl, VO2+, center. In 1993, it was discovered by crystallographic characterization that amavadin is not a vanadyl ion
The vanadyl or oxovanadium(IV) cation, VO2+, is a functional group that is common in the coordination chemistry of vanadium. Complexes containing this functional group are characteristically blue and paramagnetic. A triple bond is proposed to ...
compound. Instead, it is an octacoordinated vanadium(IV) complex. This complex is bonded to two tetradentate ligands derived from N-hydroxyimino-2,2'-dipropionic acid, H3(HIDPA), ligands. The ligands coordinate through the nitrogen and the three oxygen centers.
Amavadin is a C2-symmetric anion with a 2− charge. The twofold axis bisects the vanadium atom perpendicular to the two NO ligands. The anion features five chiral centers, one at vanadium and the four carbon atoms having S stereochemistry. There are two possible diastereomers for the ligands, (''S'',''S'')-(''S'',''S'')-Δ and (''S'',''S'')-(''S'',''S'')-Λ.
Biological function
The biological function of amavadin is still unknown, yet it has been thought that it uses H2O2 and acts as aperoxidase
Peroxidases or peroxide reductases ( EC numberbr>1.11.1.x are a large group of enzymes which play a role in various biological processes. They are named after the fact that they commonly break up peroxides.
Functionality
Peroxidases typically ca ...
to aid the regeneration of damaged tissues. Amavadin may serve as a toxin for protection of the mushroom.
References
{{Poisonous Amanitas Vanadium(V) compounds Mycotoxins found in Basidiomycota