The interaction of Eu(iii) with organoborates – a further approach to understand the complexation in the An/Ln(iii)–borate system

Autor: Thorsten Stumpf, Margret Acker, Vinzenz Brendler, Astrid Barkleit, Steffen Taut, Jerome Kretzschmar, Juliane Schott, Satoru Tsushima, Björn Drobot
Rok vydání: 2015
Předmět:
Zdroj: Dalton Transactions. 44:11095-11108
ISSN: 1477-9234
1477-9226
Popis: 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.
Databáze: OpenAIRE