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.

Speciation Studies of Metals in Trace Concentrations: The Mononuclear Uranyl(VI) Hydroxo Complexes

“…Its high sensitivity enables luminescence studies below saturation; however, data deconvolution as well as signal-to-structure correlation is not straightforward. Parallel factor analysis (PARAFAC) was demonstrated to be a useful tool for luminescence data deconvolution. ,, …”

Uranium(VI) Complexes of Glutathione Disulfide Forming in Aqueous Solution

“…Parallel factor analysis , was used for TRLFS data deconvolution. Accordingly, the N-way toolbox for matlab was used as previously described for other TRLFS data. − …”

Interaction of Np(v) with borate in alkaline, dilute-to-concentrated, NaCl and MgCl2solutions

“…8,9 Only a very limited number of experimental studies available in the literature deal with the impact of borate on the solution chemistry of actinides. [10][11][12][13][14][15] Most of these studies focus on Nd(III), Eu(III) and Cm(III) as analogues of the trivalent actinides Am(III) and Pu(III). [10][11][12][13] Spectroscopic and solubility data indicated the formation of relatively weak Cm(III)borate(aq) and Ln(III)-borate(aq) complexes in mildly alkaline aqueous solutions.…”

“…[10][11][12][13][14][15] Most of these studies focus on Nd(III), Eu(III) and Cm(III) as analogues of the trivalent actinides Am(III) and Pu(III). [10][11][12][13] Spectroscopic and solubility data indicated the formation of relatively weak Cm(III)borate(aq) and Ln(III)-borate(aq) complexes in mildly alkaline aqueous solutions. [10][11][12][13] On the other hand, the most distinct feature observed in was the formation of a previously unreported Nd(III)-borate(s) amorphous solid phase that defined solubility limits well below the solubility of Nd(OH) 3 (s) in weakly alkaline solutions.…”

“…[10][11][12][13] Spectroscopic and solubility data indicated the formation of relatively weak Cm(III)borate(aq) and Ln(III)-borate(aq) complexes in mildly alkaline aqueous solutions. [10][11][12][13] On the other hand, the most distinct feature observed in was the formation of a previously unreported Nd(III)-borate(s) amorphous solid phase that defined solubility limits well below the solubility of Nd(OH) 3 (s) in weakly alkaline solutions. 13 In her PhD thesis, Hinz revealed also no (or very minor) impact of borate on the solubility of Th(IV), very likely as a result of the strong An(IV) hydrolysis that cannot be outcompeted by borate complexation.…”