Complexation of N-acyl-N′-(p-toluenesulfonyl)hydrazines with nonferrous metal ions in ammoniac media

The complexation of N-acyl-N′-(p-toluenesulfonyl)hydrazines (ASHs) with copper(II), cobalt(II), nickel(II), zinc(II), cadmium(II), and silver(I) ions in ammoniac media was studied. The reagents were shown to form compounds with [M]: [ASH] ratios of 1: 1 and 1: 2 in solutions. ASH complexes with metal ions were preparatively separated and identified. The quantitative characteristics of complexation equilibria—the solubility products of precipitates—were found. The effects of ammonium salts and the length of a radical on the completeness of precipitation of M(II) cations with ASH were studied.     

Spectroscopic and TDDFT studies of N-phenyl-N′-(3-triazolyl)thiourea) compounds with transition metal ions

Reaction of N-phenyl-N′-(3-triazolyl)thiourea) (H₃L) with M(ClO₄)₂ (M = Co(II) (1), Ni(II) (2) and Cu(II) (3)) afforded [M(H₂L)₂] complexes, which were characterized experimentally and theoretically using different analytical, and spectral tools. The susceptibility of Staphylococcus aureus and Escherichia coli bacteria towards H₃L and its complexes was evaluated. The thiourea ligand coordinates to the 3d-metal ions via C–S^?, and triazole nitrogen yielding coordination compounds between the tetrahedral, and square-planar geometries (“flattened” tetrahedron, D₂d symmetry). Full geometry optimization, vibrational analyses, and natural bond orbital analyses of the proposed conformations of 1–3 were executed at B3LYP/def2-SVP to gain some knowledge about the local minima structures, natural charge of the coordinated metal ion, electronic configuration as well as the hybridization of M–L bonds. The electronic structures of the local minimum structures of 1–3 were investigated by time-dependent density functional theory calculations. Coordination of the thiourea ligand to Co(II) and Cu(II) ions did alter the toxicity against the tested microbes, while chelation of Ni(II) ion gave rise to inactive species.     

Complexation and extraction studies of lanthanide ions by 1,1′-(3,6,9-Trioxaundecanedionyl)Diphenothiazine

Solid complexes of lanthanide picrates with 1,1′-(3,6,9-trioxaundecanedionyl)diphenothiazine (L), [Ln(pic)₃L] (Ln = La, Nd, Eu, Gd, Er, Y), have been prepared and characterized by elemental analysis, IR and ¹H NMR spectra. The molecular structure of [Er(pic)₃L]·1/2C₂H₅OH shows that five oxygens of L form a ring-like coordination structure. Er(III) is 9-coordinated by L together with the other two unidentate and one bidentate picrate anions, revealing a tri-capped distorted trigonal prism geometry. Solvent extraction of Ln(III) with L has been carried out in a water–nitrobenzene system by use of the multitracer method. The relationship between the complex structure and extractabilities of the ligand is discussed.     

The structure of Fe(III) ions in strongly alkaline aqueous solutions from EXAFS and Mössbauer spectroscopy

To establish the structure of ferric ions in strongly alkaline (pH > 13) environments, aqueous NaOH solutions supersaturated with respect to Fe(III) and the solid ferric-hydroxo complex salts precipitating from them have been characterized with a variety of experimental techniques. From UV measurements, in solutions of pH > 13, only one kind of Fe(III)-hydroxo complex species was found to be present. The micro crystals obtained from such solutions were proven to be a new, so far unidentified solid phase. M?ssbauer spectra of the quick-frozen solution and that of the complex salt indicated a highly symmetrical ferric environment in both systems From the EXAFS and XANES spectra, the environment of the ferric ion in these solutions (both native and quick-frozen) and in the complex salt was found to be different. In the complex salt, the bond lengths are consistent with an octahedral coordination around the ferric centres. In solution, the coordination geometry of Fe(III) is most probably tetrahedral. Our results demonstrate that in strongly alkaline aqueous solutions, ferric ions behave very similarly to other structurally related tervalent ions, like Al(III) or Ga(III).     

Extraction of copper(II) ions from ammonia solutions with a β-diketone extractant

The extraction of copper(II) ions from ammonia solutions with a new β-diketone extractant, DX-510A, has been studied. Kinetic features of the copper(II) extraction and back extraction have been established: the reaction orders have been determined, and extraction and stripping rate constants have been calculated to be k_e1 = 4.14 × 10^–2 s^–1 and k_be1 = 3.20 × 10^–2 s^–1, respectively. It has been demonstrated that the extraction of copper(II) ions is not accompanied by the coextraction of ammonia. The type of extracted complex has been determined and its formula has been suggested.     

Complexation equilibria and spectrophotometric determination of zinc (II) with 2-(4′-methyl-2′-thiazolylazo)-4,6-dimethylphenol

2-(4′-methyl-2′-thiazolylazo)-4,6-dimethylphenol has been synthesized and its acid—base behaviour (pK_a1=0.03 ± 0.01, pK_a2=9.70±0.09) and complexation equilibria with zinc (logβ₁₀₁=6.70±0.04, logβ₁₀₂ = 13.70±0.02) studied in a 40% (v / v) ethanol—water medium at I=0.25 M NaClO₄. A spectrophotometric method for the determination of 0.2–1.5 ppm of zinc has been developed (ε=1.83 × 10⁴ 1. mol⁻¹ cm⁻¹ at 590 nm) and applied to its determination in lubricating oils.     

Complexation of copper(II) with 2′,2′-dialkyl-para-tert-butylbenzohydrazides

The complexation of copper(II) with 2′,2′-dimethyl-, 2′,2′-dibutyl-, and 2′,2′-diisobutyl-para-tert-butylbenzohydrazide in water-ethanol media was studied. The reagents (HL) formed [Cu(HL)]²⁺ and [Cu(HL)₂]²⁺ cationic complexes in a weakly acidic medium and uncharged CuL₂ complexes in an alkaline medium. logK _st was calculated for these complexes. The effect of 2′,2′-alkyl radicals on the stability of the complexes was considered. The obtained results were compared with data on the complexation of copper(II) ions with 2′,2′-dialkylbenzohydrazides.     

Equilibrium and kinetics of copper extraction from acidic sulfate solutions with isomeric 1-(2′-hydroxy-5′-alkyl-phenyl)-1-alkanone (E)-oximes

Equilibrium and kinetic data were determined for copper extraction by individual 1-(2-hydroxy-5-nonylphenyl)-1-ethanone (E)-oxime and 1-(2-hydroxy-5-methylphenyl)-1-decanone (E)-oxime having different locations of the nonyl group. Solubility in water, partition of oximes between water and toluene and the interfacial tension isotherms were also determined and used to interpret kinetic data and to discuss the mechanism of copper extraction. 1-(2-hydroxy-5-nonylphenyl)-1-ethanone (E)-oxime extracts the same amount of copper and at the same pH range as 1-(2-hydroxy-5-methylphenyl)-1-decanone (E)-oxime. The extraction rate is much faster for copper extraction with 1-(2-hydroxy-5-nonylphenyl)-1-ethanone (E)-oxime. This can be qualitatively explained by its higher solubility in aqueous solutions or by its better adsorption and orientation at the interfaces as the bulk volume process or the interfacial process are considered.     

Kinetics of solvent extraction of metal ions with HDEHP—I Kinetics and mechanism of solvent extraction of Ti(IV) from acidic aqueous solutions with bis-(2-ethyl hexyl) phosphoric acid in benzene

The rate of extraction of Ti(IV) from aqueous sulphuric acid solution into benzene with HDEHP [HDEHP = H₂A₂ = bis-(2-ethyl hexyl)-phosphoric acid] and back extraction of the Ti(IV)-DEHP chelate from the benzene phase to an aqueous phase have been studied under various conditions. The distribution equilibria have also been investigated. The structure of the extracted species has been investigated by IR spectral data, molecular weight determination and phosphorous-titanium atom ratio determination. The extracted species has been shown to be [TiOA₂]₃. From the extraction equilibrium studies, the reaction for the extraction of Ti(IV) has been proposed and the extraction equilibrium constant has been evaluated.The rate of forward extraction is proportional to [(TiO)⁺²]³, [H₂A₂]_(org)⁺³ and [H₂SO₄]⁻³, whereas the rate of backward extraction is proportional to [TiOA₂]_(org)⁺¹, [H₂A₂]_(org)⁻¹ and [H₂SO₄]⁻¹. The rate determining step in the forward extraction involves the reaction of 3 atoms of titanium in a stable chain or ring with 3 molecules of HDEHP dimer molecules. The rate of backward extraction studies indicate that the rate determining step of the backward extraction involves the reaction of [TiOA₂] molecule with one molecule of H₂SO₄. The values of the equilibrium constants obtained from the equilibrium study and rate study are 10^{(3.646±0.16)} and 10^{(10.604±0.194)} respectively. The cause of this discrepancy has been explained.     

Kinetics of oxidation of 4,4′-biphenyldiol and of 4,4′-biphenoquinone by metal ions in aqueous perchlorate media: Reactions with Mn(III), Ce(IV) and Ag(II)

The kinetics and mechanisms of the oxidation of 4,4′-biphenyldiol ([1,1′-biphenyl]-4,4′-diol, I) to 4,4-biphenoquinone ([bi-2,5-cycloexadiene-(1,1′-cycloexadiene-(1,1′-ylidene)]-4,4′-dione, II) as well as the oxidative decomposition of II by means of some metal ions (Mn^III, Ce^IV and Ag^II) have been investigated in aqueous perchlorate media at different temperatures and acidities. The oxidation of I follows the empirical rate law: $\text{−}\text{d[I}\text{]}\text{d}\text{t}\text{= k[}\text{I][M}\text{]f([}\text{H}{}^{\mathrm{+}}\text{])}$, where M represents the oxidizing metal ion, and the decomposition of II: $\text{−}\text{d[II]}\text{d}\text{t}\text{= k′[}\text{II}\text{][}\text{M}\text{]}{}^{\mathrm{a}}\text{f′([}\text{H}{}^{\mathrm{+}}\text{])}$, where a = 1 for Ag^II and a = 0 for Ce^IV and Mn^III. The reaction mechanisms are proposed.     

Complexation of metal ions with double-armed diazadithia lariat ether carrying anthracene moieties in acetonitrile–dioxane

A new 14-membered crown ether with nitrogen–sulfur donor atom carrying two anthryl groups was designed and synthesized by the reaction of the corresponding macrocyclic compound and 9-(chloromethyl) anthracene. The influence of metal cations such as Al³⁺, Zn²⁺, Fe²⁺, Fe³⁺, Co²⁺, Ni²⁺, Mn²⁺, Cu²⁺, Cd²⁺, Hg²⁺ and Pb²⁺ on the spectroscopic properties of the ligand was investigated in acetonitrile–dioxane solution (1/1) by means of absorption and emission spectrometry. The results of spectrophotometric titration experiments disclosed the complexation stoichiometry and complex stability constant of the novel ligand with Fe²⁺, Fe³⁺, Al³⁺, Cd²⁺, Cu²⁺, Zn²⁺, Pb²⁺ and Hg²⁺ cations. Absorption spectra show isobestic points in the spectrophotometric titration of these cations. The presence of excess of Al³⁺, Zn²⁺, Fe²⁺, Fe³⁺, Co²⁺, Ni²⁺, Mn²⁺, Cu²⁺, Cd²⁺, Hg²⁺ and Pb²⁺ cations caused an enhancement of anthryl fluorescence. Especially, the enhancement in case of the interaction of Hg²⁺ and Al³⁺ cations with the ligand was pronounced.     

Interaction of adenosine 5′ triphosphate with some dipositive metal ions and isolation and characterization of some novel solid compounds

The isolation and characterization of some dipositive metal ions-ATP complexes have been described. The isolated solid compounds have the composition Na₂M(ATP)nH₂O where n = 2 for M = Ca(II), Mn(II), Fe(II), Co(II), Zn(II) and VO²⁺; n = 3 for M = Mg(II), and n = 4 for M = Ni(II), Hg(II) and Pd(II), or Na₂M₃(ATP)₂6H₂O where M = Cu(II) and Cd(II), whereas dioxouranium(VI) ion affords NaUO₂(ATPH)2H₂O. The water soluble complexes exhibit 2:1 electrolytic behaviour which is in conformity with the constitutions suggested. The magnetic susceptibilities of the Mn(II), Fe(II), Co(II) and Ni(II) complexes suggest that they have the pseudo-octahedral geometry which fact is supported for Ni(II) and Co(II) compounds by the electronic spectra. The D_q value of ATP⁴⁻ calculated from the ligand field spectra suggest that its position in the spectrochemical series should be very close to that of H₂O. IR spectra suggest that in most of the cases the metal ions are linked both to the phosphates and to the bases [N(7)] of the adenosine-5′-triphosphate molecule.     

Synthesis and structural characterization of three supramolecular coordination polymers constructed from different metal ions and 2,2′-bipyridyl-3,3′-dicarboxylic acid

Three new supramolecular coordination polymers based on 2,2′-bipyridyl-3,3′-dicarboxylic acid (H₂BPDC) and Mn(II), Fe(II), and Zn(II) were synthesized under hydrothermal conditions and characterized with single-crystallographic X-ray analysis and IR spectrum. Complex 1 exhibits a 1-D, chain-like structure, which is further connected to 2-D supramolecular layer structure through hydrogen bonds. Complex 2 exhibits a 3-D supramolecular structure constructed from 1-D chains through hydrogen bonds and π–π interactions. Like 1, 3 also shows 2-D supramolecular layer structure based on 1-D chains. Furthermore, the fluorescence of 3 was studied.     

Solvent extraction of metal ions from aqueous solutions containing N,N,N′,N′-ethylenediaminetetraacetic and related acids—II. La(III) and diethylenetriaminepentaacetic acid

In the absence of a competing anion, [La(DTPA)]²⁻ was extracted from aqueous phases in the pH ranges 1–3 by the perchlorate salt of the primary amine Primene JM-T. The addition of small amounts of SO²⁻₄ to the aqueous phases depressed the extraction of La to near zero. As the SO²⁻₄ concentration was increased further, D_La increased to values greater than that found in the absence of SO²⁻₄; this was caused by a change in the mechanism of extraction and [La(SO₄)₂]⁻ became the extracted species.     

Recovery of tungsten(VI) and molybdenum(VI) with N′,N′-dialkylhydrazides of aliphatic carboxylic acids from acid solutions

Russian Journal of Applied Chemistry - Recovery of tungsten(VI) with solutions of N′,N′-dialkylhydrazides of 2-ethylhexanoic and octanoic acids in kerosene from sulfuric acid and...     

A Spectrophotometric Study of Complexation Between Nickel(II) and 4-(5′-Methyl-3′-Isoxazolylazo)Resorcinol

Abstract

The complexation equilibria between Ni(II) and 4-(5′-methyl-3′-isoxazolylazo)resorcinol have been spec-trophotometrically studied in a 20% (v/v) ethanol-water medium at 0.1M NaCIO₄ ionic strength and species NiHR (log β₁₁₁ = 14.83 ± 0.05), NiR (log β₁₀₁ = 9.32 ± 0.04) and NiR₂ (log β₁₀₂ = 17.84 ± 0.05) are established.     

Complexation of metal ions with the novel azathia crown ethers carrying anthracene pendant in acetonitrile–dichloromethane

A series of crown ethers carrying an anthracene group with nitrogen–sulfur donor atom, which differ in having three, four and five sulfur atoms in the macrocycle was designed and synthesized by the reaction of the corresponding macrocyclic compound and 9-chloromethyl-anthracene. The influence of metal cations such as Al³⁺, Zn²⁺, Fe²⁺, Fe³⁺, Co²⁺, Ni²⁺, Mn²⁺, Cu²⁺, Cd²⁺, Hg²⁺ and Pb²⁺ on the spectroscopic properties of the ligands was investigated in acetonitrile–dichloromethane (1:1) by means of absorption and emission spectrometry. Absorption spectra show isosbestic points in the spectrophotometric titration of Al³⁺, Zn²⁺, Fe²⁺, Fe³⁺, Cu²⁺, Hg²⁺ and Pb²⁺ the results of which disclosed the complexation compositions and complex stability constants of the novel ligands with these cations. The monoazapentathia crown ether showed sensitivity for Al³⁺ with linear range and detection limit of 2.6 × 10⁻⁶ M–2.6 × 10⁻⁵ M and 8.1 × 10⁻⁷ M, respectively.