title: The interaction of Eu(III) with organoborates – a further approach to understand the complexation in the An/Ln(III)-borate system.
abstract: The formation equilibria of salicylatoborate, lactatoborate and 3-hydroxybutyratoborate were studied by means of (11)B NMR spectroscopy. The smaller the pKa of the respective organic acid, the higher is the formation constant of the organoborate. The complexation of Eu(III) with salicylatoborate and lactatoborate was investigated by means of TRLFS (time-resolved laser-induced fluorescence spectroscopy) and (11)B NMR spectroscopy, yielding complexation constants lg β₁₁⁰ = 2.6-3.2. A Eu(III)-3-hydroxybutyrate complex was characterized by TRLFS and (1)H NMR spectroscopy (lg β₁₁⁰ = 2.89). DFT calculations of the investigated Eu(III)-organoborates and inorganic Eu(III)-(poly)borates provided information about the Eu(III) coordination (most likely chelate). They support the hypothesis that the complexation of Eu(III) with organic as well as inorganic borate structures containing the binding site "B(OR)4(-)" (R = H, threefold coordinated boron center(s), organic moiety) is comparable.
authors.affiliation: Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, Bautzner Landstraße 400, 01328 Dresden, Germany.
authors.forename: Juliane
authors.initials: J
authors.lastname: Schott
authors.forename: Jerome
authors.initials: J
authors.lastname: Kretzschmar
authors.forename: Satoru
authors.initials: S
authors.lastname: Tsushima
authors.forename: Björn
authors.initials: B
authors.lastname: Drobot
authors.forename: Margret
authors.initials: M
authors.lastname: Acker
authors.forename: Astrid
authors.initials: A
authors.lastname: Barkleit
authors.forename: Steffen
authors.initials: S
authors.lastname: Taut
authors.forename: Vinzenz
authors.initials: V
authors.lastname: Brendler
authors.forename: Thorsten
authors.initials: T
authors.lastname: Stumpf