Study on the isomerism in meso-amavadin and an amavadin analogue

Abstract

An X-ray crystallographic study of 'meso-amavadin' revealed that in the crystal the negatively charged anionic species of the title compound join into infinite hydrogen-bonded chains, counterbalanced by cationic hydronium species. Along with water of crystallization a three-dimensional hydrogen-bonded network is formed. Based on NMR-and X-ray data of amavadin and 'meso-amavadin', a model was developed that accounts for the structure of amavadin-type complexes, i.e. vanadium(IV) non-oxo complexes that contain two ligands with a tridentate N-hydroxyiminodiacetate backbone. The model describes the different arrangements of the two ligands around the vanadium and it accounts for eventual symmetry in the complex. The model was used for the interpretation of NMR-data of an amavadin analogue with a benzyl group at the ligand backbone.

Amavadin and Homologues as Mediators of Water Oxidation

“…Amavadin is a natural vanadium(IV) compound bearing the [V(S,S‐HIDPA) 2 ] 2− complex anion with two fully deprotonated ( S , S )‐ N ‐hydroxyimino‐(2,2′)‐dipropionate ligands (Figure A) . A few models of this metallobiomolecule have been characterized, as well as the corresponding oxidized complexes . Its biological role is yet unknown, but it exhibits peroxidase‐ and catalase‐type activities .…”

Molecular and supramolecular ionic aggregates HxOyzin organic and organometallic crystalline hydrates

“…10a; FEGTEQ ;Hanson, 1987), while isomer 2 consists of two extra annular Zundel cations attached to a ring of four water molecules ( Fig. 10b; WIDTEJ; Hubregtse et al, 2007).…”

PHARMACOLOGICALLY AND TOXICOLOGICALLY RELEVANT COMPONENTS OF Amanita muscaria

“…The measured vanadium concentration in the toadstools was 400 times higher than its concentration in the surrounding vegetation, irrespective of the age of the fruit and the vanadium content of the forest soil, and reached values of 32-192 mg/kg of dry weight of the fruit (Meisch et al, 1979). Although the role of vanadium and its remarkable complex compounds in the toadstool remains unclear, in any case, amavadine is an extremely interesting bio-organic molecule (Hubregtse et al, 2007;Patočka, 2010). The selective enrichment of metals in nature is of great interest.…”