Speciation, thermodynamics and structure of Np(v) oxalate complexes in aqueous solution

2020 ◽  
Vol 49 (38) ◽  
pp. 13359-13371
Author(s):  
M. M. Maiwald ◽  
M. Trumm ◽  
K. Dardenne ◽  
J. Rothe ◽  
A. Skerencak-Frech ◽  
...  

The speciation, thermodynamics and structure of the Np(v) (as the NpO2+ cation) complexes with oxalate (Ox2−) are studied by different spectroscopic techniques.

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Adedibu C. Tella ◽  
Janet T. Bamgbose ◽  
Vincent O. Adimula ◽  
Mary Omotoso ◽  
Sunday E. Elaigwu ◽  
...  

AbstractThe interaction of eosin B dye from aqueous solution with MIL-100(Fe) and functionalized MIL-100(Fe) metal–organic frameworks (MOFs) is reported in this study. MIL-100(Fe) was prepared and functionalized with thioglycolic acid (TH) and ethylenediammine (ED) separately by incorporating the thiol (–SH) and the amine (–NH2) group of the functionalizing agents into the open metal sites of the MIL-100(Fe) to obtain the acidic (TH-MIL-100) and basic (ED-MIL-100) forms of the MOF respectively. Characterization of the MOFs was done by melting point analysis, elemental analysis, spectroscopic techniques, scanning electron microscopy (SEM), and powdered X-ray diffraction (PXRD) analysis. The adsorption experiments were carried out at different conditions such as pH, adsorbent dosage, contact time, temperature, and initial concentration of the dye to estimate the optimum conditions and the maximum adsorption capacities. Adsorption capacities were observed to increase in the order of ED-MIL-100 < MIL-100 < TH-MIL-100, while the TH-MIL-100 was the most effective in the removal process due to acid–base interaction between the acidic thiol group (–SH) and the alkaline medium of eosin B dye solution. The Langmuir Isotherm was seen to fit well to adsorption data obtained for all three adsorbent materials studied, and adsorption processes followed the pseudo-second order kinetics. This study, therefore, indicates the suitability of functionalization of MIL-100(Fe) towards improving its adsorption capacity.


2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Amer A. G. Al Abdel Hamid ◽  
Mohammad Al-Khateeb ◽  
Ziyad A. Tahat ◽  
Mahmoud Qudah ◽  
Safwan M. Obeidat ◽  
...  

A new ruthenium(II) complex (cis-ruthenium-bis[2,2′-bipyridine]-bis[4-aminothiophenol]-bis[hexafluorophosphate]) has been synthesized and characterized using standard analytical and spectroscopic techniques, FTIR, 1H and 13C-NMR, UV/vis, elemental analysis, conductivity measurements, and potentiometric titration. Investigation of the synthesized complex with metal ions showed that this complex has photochemical properties that are selective and sensitive toward the presence of mercuric ion in aqueous solution. The detection limit for mercuric ions using UV/vis spectroscopy was estimated to be ~ 0.4 ppm. The results presented herein may have an important implication in the development of a spectroscopic selective detection for mercuric ions in aqueous solution.


1979 ◽  
Vol 57 (9) ◽  
pp. 1018-1024 ◽  
Author(s):  
Ramunas J. Motekaitis ◽  
David Hayes ◽  
Arthur E. Martell ◽  
Wayne W. Frenier

The hydrolysis and ammonolysis of EDTA were studied in aqueous solution over a range of temperatures and at various pH values with the aid of nmr, gc, and gc – mass spectroscopic techniques. At high pH in the presence of ammonia, both ammonolysis and hydrolysis occur with the production of N-(2-aminoethyl)iminodiacetic acid (UEDDA), N-(2-hydroxyethyl)-iminodiacetic acid (HEIDA), and iminodiacetic acid (IDA) in molar ratios such that [IDA] = [UEDDA] + [HEIDA]. The first-order rate constant for the disappearance of EDTA at 175 °C in dilute aqueous ammonia is 8.6 × 10−5 s−1 whereas in the absence of ammonia its hydrolysis constant is 4.2 × 10−5 s−1. The value of ΔH0 for this reaction is approximately 35 kcal/mol. When methylamine replaces ammonia, the UEDDA is replaced by N-(2-methylaminoethyl)iminodiacetic acid. The rate of hydrolysis is increased by the presence of a tertiary amine but the latter does not become incorporated into the reaction products. A reaction mechanism is proposed involving bimolecular SN2 attack by base on a carbon atom of the ethylene bridge adjacent to a protonated nitrogen atom of EDTA with concomitant displacement of iminodiacetic acid.


1972 ◽  
Vol 94 (19) ◽  
pp. 6655-6665 ◽  
Author(s):  
Anthony F. Vaudo ◽  
Evan R. Kantrowitz ◽  
Morton Z. Hoffman ◽  
Elias Papaconstantinou ◽  
John F. Endicott

2008 ◽  
Vol 12 (08) ◽  
pp. 942-952 ◽  
Author(s):  
Patrícia S. Santiago ◽  
Shirley C.M. Gandini ◽  
Leonardo M. Moreira ◽  
Marcel Tabak

The equilibrium of meso-tetrakis(4-N-methylpyridiniumyl)porphyrin (TMPyP) in aqueous solution in the presence of surfactants was studied by optical spectroscopic techniques and SAXS (small angle X-ray scattering). Anionic SDS (sodium dodecyl sulfate), zwitterionic HPS (N-hexadecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate) and nonionic TRITON X-100 (t-octylphenoxypolyethoxyethanol), surfactants were used. TMPyP is characterized by a protonation equilibrium with a pKa around 1.0, associated with the diacid-free base transition, and a second pKa around 12.0 related with the transition between the free base and the monoanion form. Three independent species were observed for TMPyP at pH 6.0 as a function of SDS concentration: free TMPyP, TMPyP-SDS aggregates and porphyrin monomer bound to micelles. For HPS and TRITON X-100, the equilibrium of TMPyP as a function of pH is quite similar to that obtained in pure aqueous solution: no aggregation was observed, suggesting that electrostatic contribution is the major factor in the interaction between TMPyP and surfactants. SAXS data analysis demonstrated a prolate ellipsoidal shape for SDS micelles; no significant changes in shape and size were observed for SDS-TMPyP co-micelles. Moreover, the ionization coefficient, α, decreases with the increase of the porphyrin concentration, suggesting the "screening" of the anionic charge of SDS by the cationic porphyrin. These results are consistent with optical absorption, fluorescence and RLS (resonance light scattering) spectroscopies data, allowing to conclude that neutral surfactants present a smaller interaction with the cationic porphyrin as compared with an ionic surfactant. Therefore, the interaction of TMPyP with the ionic and nonionic surfactants is predominantly due to the electrostatic contribution.


1993 ◽  
Vol 48 (5-6) ◽  
pp. 430-435 ◽  
Author(s):  
Norihiko Terahara ◽  
Kenjiro Toki ◽  
Toshio Honda

Abstract The structures of the two pigments in the red Cineraria, Senecio cruentus, flowers have been identified as malonylcaffeylcyanidin 3,3′-diglucoside (2) and as its demalonyl compound (1), new anthocyanins, by using chromatographic and spectroscopic techniques involving UV-VIS, IR, FAB-MS and NMR . In a neutral aqueous solution, the acylated anthocyanins retained their colorings for a long time.


2003 ◽  
Vol 91 (12) ◽  
Author(s):  
Christophe Den Auwer ◽  
A. C. Grégoire-Kappenstein ◽  
Ph. Moisy

AbstractActinide cation–cation complexes in aqueous solution have long been a subject of interest. Since the former work of Sullivan


2014 ◽  
Vol 70 (a1) ◽  
pp. C564-C564
Author(s):  
Arie Van Der Lee ◽  
Dan Dumitrescu ◽  
Yves-Marie Legrand ◽  
Eddy Petit ◽  
Mihail Barboiu

Confined alkanes within molecular capsules are an intriguing research area which were studied until now only by spectroscopic techniques, but never by single-crystal X-ray techniques [1-2]. We report here an extremely simple molecular flask made up by hydrogen-bonded tectons, which is used as a container for diammonium alkane chains of variable sizes. It was obtained in aqueous solution as well as in the crystalline state by mixing commercially available components: 1,3,5,8-pyrenetetrasulfonate (PTS), guanidinium (G) and 1,ω-diammonium-alkanes (Figure A). 1,10-diammoniumdecane 1 fits perfectly inside the capsule, while the 1,11-diammonium-undecane 2 and 1,12-diammonium-dodecane 3 chains are progressively compressed. Furthermore, it was observed that the compressed conformers may be stabilized by short dihydrogen contacts (Figure B).


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