title: Extraction and DFT study on the complexation of Zn(2+) with beauvericin.
abstract: From extraction experiments and g-activity measurements, the exchange extraction constant corresponding to the equilibrium Zn2+(aq) + 1 . Sr2+(nb) <-> 1 . Zn2+(nb) + Sr2+(aq) taking place in the two-phase water-nitrobenzene system (1 = beauvericin; aq = aqueous phase, nb = nitrobenzene phase) was evaluated as log Kex (Zn2+, 1 . Sr2+) = -0.3 ± 0.1. Further, the stability constant of the beauvericin - zinc complex (abbrev. 1 . Zn2+) in nitrobenzene saturated with water was calculated for a temperature of 25 °C: log βnb (1 . Zn2+) = 9.1 ± 0.2. Finally, by using quantum mechanical DFT calculations, the most probable structure of the 1 . Zn2+ complex species was predicted.
authors.forename: Emanuel
authors.initials: E
authors.lastname: Makrlík
authors.forename: Petr
authors.initials: P
authors.lastname: Toman
authors.forename: Petr
authors.initials: P
authors.lastname: Vaňura
mesh_terms: D047630:Depsipeptides / Q000737:chemistry / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008958:Models, Molecular; D015394:Molecular Structure; D009578:Nitrobenzenes / Q000737:chemistry / Q000378:metabolism*; D011789:Quantum Theory; D013324:Strontium / Q000737:chemistry / Q000378:metabolism*; D014867:Water / Q000737:chemistry / Q000378:metabolism*; D015032:Zinc / Q000737:chemistry / Q000378:metabolism*
chemical_list: D047630:Depsipeptides; D009578:Nitrobenzenes; D014867:Water; C004456:beauvericin; C036077:nitrobenzene; D015032:Zinc; D013324:Strontium