N. D. Mitrofanova

Influence of cyclization of N,N′-ethylenediaminedisuccinic acid on its complex-forming properties

Conclusions1.A study has been made of the conditions for the occurrence of strucutral rearrangement when an aqueous solution of N,N′-ethylenediaminedisuccinic acid is heated in acid; this chelating agent, like other analogs of ethylenediaminediacetic acid, undergoes intramolecular cyclization, with a substantial decrease in its complex-forming properties.2.The hypothesis advanced in the literature that the chelating agent is decarboxvlated is not in accord with the facts.

Mechanism of the ion-exchange separation of mixtures of rare earth elements during elution with solutions of nitrilotriacetic acid

1. The composition of complex compounds of the REE, formed during their elution from an ion-exchange resin by solutions of salts of nitrilotriacetic acid, was studied. 2. The separation of mixtures of REE is accomplished on account of mono- and dinitrilotriacetates. In the adsorption zone, mononitrilotriacetates LnX predominate, while in the zone of separation, saturated with NH 4 + ions or “retaining ions” (Cu2+), the mononitrilotriacetates are converted to dinitrilotriacetates [LnX2]3−. 3. When the resin of the zone of separation is saturated with Cu2+ ions, there is practically no contact between the REE nitrilotriacetates and the resin in the Cu2+-form. The retaining action of Cu2+ is associated with the formation of a layer of resin with an increased content of hydrogen ions between the zone of CuR2 and the zone of LnR3.

Synthesis and study of transition metal complexes with iminodisuccinic acid

Conclusions1.Protonated, neutral (mixed), and binuclear Cu(II), Ni(II), Co(II), Zn(II), and Mn(II) iminodisuccinate complexes have been synthesized.2.Based on the results of IR-spectroscopic, thermal, and other methods of analysis, various conclusions have been drawn concerning the structures of these complexes; for instance, in the case of complexes of composition H2ML·nH2O both carboxyl groups are protonated, and one of them is coordinated to the metal ion.

Chromatographic separation of mixtures of europium and gadolinium with ethylenediaminedisuccinic acid

Conclusions1.The chromatographie separation of mixtures of micro- and macroquantities of Eu and Gd with the use of ethylenediaminedisuccinic acid (EDDS) and ethylenediaminetetraacetic acid (EDTA) has been investigated. It has been shown that EDTA is a sufficiently efficient agent for the separation of this element pair.2.The αGdGd values obtained in experiments with microquantities of REE are not obtained in the separation of macroquantities of Eu-Gd; this is evidently related to the influence of polymerization processes in systems containing EDDS complexes of REE.

Preparation and properties of solid rare-earth Β-hydroxyethyliminodiacetates

Conclusions1.The authors have synthesized for all the rare earths the hitherto undescribed solid mono-Β-hydroxyethyliminodiacetates of the composition LnZCl·4H2O.2.They have subjected the LnZCl·4H2O to x-ray, thermogravimetric, and derivatographic analysis. They have investigated the IR spectra of the hydrates and anhydrous LnZCl, and their deuteroderivatives.3.From the data obtained, they infer that LnZCl·4H2O are polymeric, and they also draw certain conclusions on the character of the bond of the Ln3+ ion with different donor groups of the ligand in these compounds.

An IR spectroscopic investigation of rare-earth hydroxyethylethylenediamine triacetates

1. The changes in the IR spectra of solid hydrates of hydroxyethylethylenediamene triacetates of REE and of their anhydrous and deuterated derivatives in the series La—Lu in the region of the most important stretching vibrations closely agree with the previously observed change in the structure of the different hydrate forms of these complexes. 2. On the basis of an analysis of the frequencies ν(C−O), ν(C−H), ν(C−N), ν(C−O)sp, and δ(O−H)sp the authors draw certain conclusions concerning the structures of solid compounds of this class.

Hydrate compositions of hydroxyethylethylenediaminetriacetates of the rare-earth elements

1. Complexes of the REE, Y, and Sc with hydroxyethylethylenediaminetriacetic acid have been isolated in solid form. The hydrate compositions of the complexes have been determined. 2. The La and Pr complexes form hydrates of different compositions. The LnL hydrates form slightly nonisostructural groups in the series La-Lu. 3. According to thermographic analysis data, the hydrate water in the LnL·nH2O complexes of different hydrate compositions is not bonded with the same firmness.

IR-spectroscopic investigation of hydroxyethylethylenediaminetriacetic acid and its potassium salt

1. The IR spectra of solid hydroxyethylethylenediaminetriacetic acid (HEDTA) and its potassium salts and their deutero derivatives were investigated. 2. From an analysis of the characteristic frequencies of the C-O, C-H, O-H, and N-H bonds it follows that HEDTA and its acid potassium salts have a betaine structure.

IR spectroscopic investigation of solid β-hydroxyethyliminodiacetic acid and its potassium salt

1. The IR spectra of solidβ-hydroxyethyliminodiacetic acid (H2X), its acid (KHX) and neutral (K2X) potassium salts, as well as their deutero-derivatives, were studied. 2. From an analysis of the vibration frequencies of the C-O, C-N, C-H, and N-H bonds, a betaine structure of H2X and its acid potassium salt follows. 3. The values of the vibration frequencies of the alcohol O-H bond in the IR spectra of H2X and KHX indicate the participation of a hydroxyl group in the formation of hydrogen bonds.

Comparative investigation of solid copper and nickel nitrilotriacetates

1. The conditions of synthesis and isolation of crystal hydrates of copper and nickel nitrilotriacetates were determined. Previously undescribed nitrilotriacetates with the composition HNiX·3H2O, KH(CuX)2·3H2O, Ni2X3·9H2O were isolated, where X3− is the acid residue of nitrilotriacetic acid. 2. The content of water of hydration in the synthesized solid nitrilotriacetates was determined. pH-metric, thermogravimetric, and x-ray diffraction investigations of copper and nickel nitriloacetates were conducted.