Ternary complex formation of Eu(III) and Am(III) with pyridine-2,6-dicarboxylate in aqueous solutions

Speciation of Eu3+ bound to humic substances by time-resolved laser fluorescence spectroscopy (TRLFS) and parallel factor analysis (PARAFAC)

“…The pH values of the samples was measured by a pH meter (ORION 5-star, Thermo Fisher Scientific) with a ROSS combined electrode (Thermo Fisher Scientific Inc., 1 M NaCl as the inner filling solution) and adjusted from 3 to 7.5 with 0.5 intervals by adding small amounts of 0.1 or 0.01 M of HClO 4 and NaOH for samples with 70 lM Eu 3+ . Above pH 7.5, the precipitation of Eu(OH) 3 (s) was expected from thermodynamic calculations by the ECOSAT program (Keizer and van Riemsdijk, 1998) with the generic parameter set for the NICA-Donnan model (Milne et al, 2003), log K sp Eu(OH) 3 (s) = À24.5 (Park et al, 2007) and hydrolysis constants of Eu 3+ reported elsewhere (Hummel et al, 2002). In the presence of 10 lM of Eu 3+ , based on similar calculations, Eu(OH) 3 (s) precipitation was less likely, and pH was changed from 3 to 10.…”

Adsorption of Eu(III) on a Heterogeneous Surface Studied by Time-Resolved Laser Fluorescence Microscopy (TRLFM)

“…For TRLFM measurement each specimen was transferred to a quartz cuvette together with the solution. Thermodynamic calculations using the solution composition (Eu(III) concentration, pH, and the salt concentration) before any adsorption took place confirmed that this Eu(III) solution under-saturated with respect to europium trihydroxide (Eu(OH) 3 ; log K sp = −24.5 ). The formation of europium hydroxocarbonate (EuOHCO 3 ; log K sp = −21.7) was slightly oversaturated and was calculated to become appreciable above pH 5.8 .…”

[Pr2(pdc)3(Hpdc)(H2O)4]n·n(H3hp)·8n(H2O), a One-Dimensional Coordination Polymer Containing PrO6N3 Tri-Capped Trigonal Prisms and PrO8N Mono-Capped Square Anti-Prisms (H2pdc = Pyridine 2,6-Dicarboxylic Acid, C7H5NO4; 3hp = 3-Hydroxy Pyridine, C5H5NO)

“…Pyridine-2,6-dicaboxylic acid (H 2 pdc, C 7 H 5 NO 4 ) is a versatile ligand that can chelate to, or bridge between, metal ions and can furnish different types of infinite-chain polymers [4][5][6][7]. As an extension of such studies, we now describe the solution-phase synthesis, crystal structure and characterization of the title compound, [Pr 2 (pdc) 3 8 ] n ·8nH 2 O [9].…”