2-thiouracil-based cobalt(II), nickel(II) and copper(II) complexes

Summary Cobalt(II), nickel(II) and copper(II) complexes of 2-thiouracil and its arylazo derivatives were prepared. The elemental analysis suggest a range of 11, 21 and 13 stoichiometries. Electronic spectra and magnetic susceptibility measurements were used to infer the structures and the i.r. spectra of the ligands and their complexes to identify the type of bonding.     

Copper(II) and copper(I) complexes of benzenecarbothioamides

Summary Copper(II) salts react with benzenecarbothioamide(BCTA);N,N-dimethylbencenecarbothioamide (DMBCTA) andN,N-diethylbenzenecarbothioamide (DEBCTA) to give complexes with 11, 21, 31 ligand/metal stoichiometric ratios, and a diamagnetic complex [Cu₂(DEBCTA)Br₄]₂ which appears to contains copper(I). These compounds were characterized by elemental analyses, conductivities measurements, i.r., electronic and e.p.r. studies and magnetic measurements.The results suggest tetrahedral geometry for the copper(II) complexes, a dimeric structure for bromide-DMBCTA and chloride and bromide-BCTA derivatives, and a square pyramid geometry for the CuBr₂-DEBCTA complex. No information is yet available on the coordination geometry of the copper(I) complex.     

Copper(II)-disulphide interaction: a spectroscopic and electrochemical study of the interaction of copper(II) with an imidazole-containing disulphide

Summary The interaction of copper(II) salts with the imidazole-containing disulphide 5-(1,2,5-dithiazaepan-5-ylmethylene)-4-methyl-2-ethyl imidazole (MAMI) in MeOH have been investigated. The 11 Cu(ClO₄)₂MAMI system exhibited a single ligand field band at ca. 12200cm^-1, an intense shoulder at ca. 31500 cm^-1 and a less intense split feature at 24400 and 25300cm^-1 assignable to S() Cu^II and S() Cu^II charge transfer (CT) transitions, respectively. The e.p.r. parameters suggested the presence of a CuN₂SO chromophore, however; the 11 Cu(NO₃)₂MAMI system did not exhibit a S Cu^II CT band and the g value was comparatively high. An electrochemical study of the 11 Cu(ClO₄)₂MAMI system in MeOH revealed that the copper-disulphide interaction, though weaker, would confer a high redox potential as well as reversibility, similar to the copper-thioether interaction.     

Solvent extraction of Zn(II), Cu(II) and Sb(III) with N-m-tolyl-p-methoxybenzohydroxamic acid (TMBHA) into chloroform

Rapid methods have been described for the quantitative extraction of milligram amounts of Zn(II), Cu(II) and Sb(III) with TMBHA into chloroform. The separation factor for many elements was found to be at least greater than 10⁴. The metal: reagent stoichiometry determined by methods like slope ratio, mole ratio and substoichiometric extraction were found to be 12 for Zn(II) and Cu(II), and 23 for Sb(III).     

Morpholine complexes of copper(II) alkanoates and chloroacetates

Summary Morpholine complexes of copper(II) alkanoates and chloroacetates of formula Cu(O₂CR)₂(Morph)_n (where R = H, Me, Et, n-Pr, i-Pr, n-Bu, i-Bu, CH₂Cl, CHCl₂ and CCl₃; Morph = Morpholine and n=1 and/or 2) have been isolated by the direct interaction of morpholine with the respective copper(II) carboxylates in a suitable organic medium and characterized by elemental analyses and various physicochemical techniques. Molecular weight determinations show that 11 complexes are dimeric whereas 21 complexes are monomeric in solution. Electronic spectra and magnetic moments suggest that 11 complexes are dinuclear carboxylate bridged species while 21 addition complexes have atrans-octahedral configuration. The i.r. spectra indicate that morpholine behaves as a monodentate ligand and coordinates through its nitrogen atom.     

Studies on the complex formation of N,N-diethylglycine with copper(II) in acetonitrile

The formation of copper(II) complexes with N,N-diethylglycine in acetonitrile has been investigated by visible, infrared as well as NMR spectral techniques. It has been found that 11 and 12 complexes are formed. In both compounds nitrogen and carboxyl oxygen of ligand molecules are involved in coordination. The stability constants are reported.

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Untersuchungen von Kupfer(II)-Komplexen mit N,N-Diethylglycin in Acetonitril

Zusammenfassung Die Bildung von Kupfer(II)-Komplexen mit N,N-Diethyglycin in Acetonitril wurde mit Hilfe von UV-VIS, IR- und NMR-Spektroskopie untersucht. Es wurde festgestellt, daß sich Komplexe der Zusammensetzung 11 und 12 bilden. In beiden Verbindungen koordinieren Stickstoff und Carboxylsauerstoff der Liganden. Die Stabilitätskonstanten wurden bestimmt.

     

Study of the complex formation between 4, 6-diamine-1, 2-dihydro-2-thiopyrimidine and cobalt(II), cobalt(III), nickel(II) and copper(II) ions

Summary Reactions of 4, 6-diamine-1, 2-dihydro-2-thiopyrimidine (HDATP) with cobalt(II), nickel(II) and copper(II) ions in 12 metal:ligand ratio in aqueous media at 25°C and 0.1 M ionic strength (KNO₃), lead to the formation of both [M(DATP)]⁺ and [M(DATP)₂] species, whose stability constants were obtained.On the other hand, in aqueous or ethanolic media, solid complexes with 11, 12, or 13 stoichiometries were isolated. These have been characterized by analytical, i.r. and electronic spectral and magnetic measurement studies, and tentative structures are proposed.     

Parent and mixed ligand complexes in the copper(II)-ethylene glycol-sulphate system

Eleven copper(II)-ethylene glycol-sulphate complexes of different compositions were prepared, one of them-CuGl₂(H₂O)₂SO₄-in single-crystal form. A thermoanalytical study of these complexes revealed three types of thermal decomposition pattern. The X-ray structure of the single-crystal demonstrated the presence of ethylene glycol bridges resulting in endless chains in the crystal.

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Zusammenfassung Elf Kupfer(II)-äthylenglykol-sulfat-Komplexe unterschiedlicher Zusammensetzung wurden dargestellt, einer davon — CuGl₂(H₂O)₂SO₄ — in Form von Einkristallen. Die thermoanalytische Untersuchung dieser Komplexe ergab drei Typen der thermischen Zersetzung. Die röntgendiffraktometrische Bestimmung der Struktur des in Form von Einkristallen erhaltenen Komplexes zeigte, daß den Kristall endlose Ketten von Äthylenglykolbrücken durchziehen.

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() — , — CuGl₂(H₂O)₂SO₄ — . . , , .

     

Extraction-spectrophotometric determination of traces of copper(II), zinc(II), cadmium(II) and mercury(II) with 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol

Summary Sensitive extraction-spectrophotometric procedures are described for the complexes of Cu(II), Zn(II), Cd(II) and Hg(II) with 5-Br-PADAP using chloroform as solvent. Optimal conditions have been established for the quantitative extraction of the metal chelates and their composition and optical characteristics have been determined as well. The conditional extraction constants amount logK _ex=10, the molar absorptivities of the complexes being 10⁵ l·mole^–1·cm^–1. Job's method and equilibrium shift method indicate the molar ratios M5-Br-PADAP=12.

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Spektralphotometrische Bestimmung von Spuren Cu(II), Zn(II), Cd(II) und Hg(II) mit 2-(5-Bromo-2-pyridylazo)-5-diethylaminophenol (5-Br-PADAP)

Zusammenfassung Einfache und empfindliche Methoden zur extraktionsspektralphotometrischen Bestimmung von Spuren Cu(II), Zn(II), Cd(II) und Hg(II) mit 5-Br-PADAP wurden beschrieben. Chloroform wurde als Extraktionsmittel verwendet. Die optimalen Bedingungen für die quantitative Extraktion der Metallchelate wurden ermittelt und deren Zusammensetzung bestimmt. Die Stabilitätskonstanten haben hohe Werte (logK _ex=10), die molare Absorption der Komplexe beträgt 10⁵1·mol^–1·cm^–1. Das Molarverhältnis der Komplexe beträgt M5-Br-PADAP=12.

     

Quantitative thermodynamic evidence of transition from hexacoordinated to tetra- and pentacoordinated structures in aqueous copper(II) and zinc(II) complexes

A calculation method previously used in the study of simple ion pairs is extended in the present work to the entropies of formation of copper(II) and zinc(II) complexes with polydentate ligands in aqueous solution. Not only a qualitative, but also a quantitative and more significant discussion of the entropy data seems possible by this method. In particular, if the literature entropy data for copper(II) complexes with some carboxylic ligands and for zinc(II) with polyamines are used, the change from 6 to 4 in the coordination number of the cation is demonstrated, in accordance with previous suggestions. In the complex(Zntren)²⁺, the metal shows a coordination number of 5, in agreement with previous X-ray results.

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Zusammenfassung Eine früher schon bei der Untersuchung einfacher Ionenpaare benutzte Berechnungsmethode wird auf die Entropiewerte der Bildung von Kupfer(II)- und Zink(II)-Komplexen mit Polydentat-Liganden in wässriger Lösung erweitert. Diese Methode scheint nicht nur eine qualitative, sondern auch eine quantitative und aussagekräftigere Diskussion der Entropiedaten zu ermöglichen. Ausgehend von Literaturangaben über die Entropie von Kupfer(II)-Komplexen mit einigen Carboxylgruppen enthaltenden Liganden und von Zink(II) mit Polyaminen wird, in Übereinstimmung mit früheren Annahmen, der Übergang von der 6-er in die 4-er Koordination demonstriert. Im Komplex (Zn tren)²⁺ ist die Koordinationszahl des Metalls 5, in Übereinstimmung mit früheren Röntgenergebnissen.

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, , . , . , 6 4, . (Zn tren)²⁺ 5, - .

     

Simultaneous determination of iron(III) and cobalt(II) withN-phenylcinnamohydroxamic acid and thiocyanate by extraction and spectrophotometry

Simple, precise, sensitive, and highly selective methods for the separate determination of iron(III) and cobalt(II) and for the simultaneous determination of both metal ions are described. Iron(III) and cobalt(II) react with thiocyanate in the presence ofN-phenylcinnamohydroxamic acid (PCHA) to form pinkish red and blue coloured complexes, respectively. Both the iron(III) and cobalt(II) complexes having stoichiometric composition of 122 (FeSCN^–PCHA) and 14 (CoSCN^–), respectively, are quantitatively extractable into ethylacetate from 0.5–1.5 M hydrochloric acid solutions. The spectra of iron(III) and cobalt(II) complexes in the visible region exhibit absorption maxima at 495 and 625 nm, respectively. The coloured systems obey Beer's law in the concentration range of 0.2–4.0g/ml of iron and 2–40g/ml of cobalt. The effects of foreign ions and of various experimental parameters were studied to establish the optimum conditions for the extraction and determination of iron and cobalt. The methods have been applied successfully to the analysis of blood, vitamin B₁₂, and standard steels for iron and cobalt.     

Synergistic extraction of cobalt(II) with resacetophenone oxime in the presence of heterocyclic nitrogen and organophosphorous compunds

Equilibrium distribution coefficients have been determined, for the extraction of cobalt(II) with resacetophenone oxime as a function of pH and reagent concentration at ambient temperature. RAPOX forms simple 12 chelate with cobalt(II). Synergistic extraction was observed with pyridine and its methyl derivatives and some organophosphorous compounds. From the extraction equilibrium data, the adduct formation constants of 12 chelate to adducting ligand adducts were evaluated.     

Complexes formed between nickel(II), copper(II), zinc(II) and aspirin

Complexes of nickel(II), copper(II) and zinc(II) with aspirin have been prepared. Examination of the complexes of nickel(II) and zinc(II) indicates that they are salicylato complexes in which the aspirin has been de-ethanoylated.Chemical, spectral and magnetic properties show that the nickel(II) and copper(II) complexes have dimeric, octahedral structures while the zinc(II) complex has a tetrahedral structure. The decomposition of the complexes was studied by thermogravimetry and differential thermal analysis. Thermal decomposition products were obtained for the nickel(II) and zinc(II) complexes. Their structures are octahedral with the exception ofbis-salicyclic acid-zinc(II) which is tetrahedral.

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Zusammenfassung Komplexe von Nickel (II), Kupfer (II) und Zink (II) mit Aspirin wurden hergestellt. Die Untersuchung der Koordinationsverbindungen von Nickel (II) und Zink (II) zeigt, daß dies Salycylatkomplexe sind, in welchen das Aspirin de-äthanoliert wurde.Die chemischen, spektralen- und magnetischen Eigenschaften zeigen, daß die Nickel (II)- und Kupfer (II)-Komplexe dimere Oktaederstrukturen besitzen, während der Zink (II)-Komplex eine Tetraederstruktur besitzt. Die Zersetzung der Komplexe wurde durch Thermogravimetrie und Differentialthermoanalyse untersucht. Thermische Zersetzungsprodukte der Nickel (II)- und Zink (II)-Komplexe wurden erhalten. Ihre Strukturen sind oktaedrich, mit Ausnahme vonBis-Salicyclosäure-Zink (II), dessen Struktur tetraedrisch ist.

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(II), (II) (II) . (II) (II) , , , . . . , , , , . . . , - , .

     

N-acetylindoxyl in the synthesis of new condensed heterocycles

Derivatives of a new heterocyclic system thieno[2,35,6]pyrimido[3,4-a]indole, were obtained by the reaction of substituted N,O-diacetylindoxyls with excess N-(2-methyl-3-ethoxycarbonyl-4-thienyl)hydrazine. The reaction of N-acetylindoxyl and 4-hydrazinouracil forms 12-amino-1,3-dioxo-2,4,6-trimethylpyrimido[5,45,6]pyrimido[3,4-a]indole.Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, 1343–1345, October, 1987.     

Thermal decomposition of bis-(DL-valinato)copper(II) and bis-(DL-methioninato)copper(II)

A kinetic study of the thermal decomposition of the complexes bis-(DL-valinato)copper(II) and bis-(DL-methioninato)copper(II) was carried out using thermogravimetry in a dynamic regime, following the theoretical model of Satava and including the equation used by Johnson and Gallagher:1/1––1=kt. Kinetic parameters were calculated and are compared with those obtained previously for the complex bis-(L-tryptophanato)copper(II). The sequence of thermal stability found is: Cu(DL-Val)₂22.

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Zusammenfassung Die thermische Zersetzung der Komplexe Bis-(DL-valinato)kupfer(II) und Bis-(DL-methioninato)kupfer(II) wurde thermogravimetrisch im dynamischen Regime untersucht, indem von dem theoretischen Modell von atava Gebrauch gemacht und die von Johnson und Gallagher benutzte Gleichung 1/1-–1=kt einbezogen wurde. Kinetische Parameter wurden berechnet und mit den kürzlich für den Komplex Bis-(L-tryptophanato)kupfer(II) erhaltenen parametern verglichen. Die Stabilität der Komplexe nimmt in folgender Reihenfolge zu: Cu(DL-Val)₂22.

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-(-)- -(L-) (II) , -: 1/1– –1=kt. -(L-) (II). Cu(DL-Val)₂22.

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Presented at the 1985 World Conference on Thermal Analysis, Bad Hofgastein, Austria.     

2-[2′-(6′-Methyl-benzothiazolyl)azo]-5-dimethylaminobenzoic acid as a new reagent for rapid spectrophotometric determination of copper

2-[2-(6-methyl-benzothiazolyl)azo]-5-dimethylaminobenzoic acid (MBTAMB) has been synthesized and employed as a new reagent for the spectrophotometric determination of copper(II). A blue complex is formed from MBTAMB and Cu(II) in the range of pH 2.0–5.0 in aqueous ethanol. The composition of the complex is Cu(II) MBTAMB=1 1. The maximum absorption of the complex is at 660 nm, its apparent molar absorptivity is 7.0 × 10⁴ 1· mole^–1 · cm^–1. Beer's law is obeyed for copper in the range of 0–0.72 g/ml. The method has been used for the determination of micro amounts of copper in aluminium alloy. The proposed method is simple, rapid and accurate.     

Reactivity of oxalates of La(III), Ba(II) and Cu(II) in ternary mixtures

Composites of cuprates of La(III) and Ba(II) were obtained by decomposing mixtures of oxalates of La(III), Ba(II) and Cu(II) prepared in 111 and 123 mol proportions respectively and sintering the oxide products at 1173 K. Reactions studied by TG, DTA and XRD techniques revealed the following features: (i) Decomposition of oxalates of La(III) and Ba(II) is drastically affected in mixtures. Decomposition temperature of organic part in the former (111) is shifted by 100 K while that of BaCO₃ in the case of latter (123) is shifted by 400 K towards lower temperature side. (ii) All exothermic peaks on DTA traces of both the mixtures are allotted to the decomposition of oxalates to Cu₂O, La₂O₂CO₃ and BaCO₃ phases while endothermic peaks around 863 and 1083 K are assigned for BaCuO₂ and La₂CuO₄ phases respectively in the case of former (111) and endothermic peaks at about 1068, 1136 and 1213 K are correlated with BaCuO₂, a composite of La₂O₃, La₂CuO₄ and La_0.5Ba_0.5CuO_3– (0.5) phases and LaBa₂Cu₃O_7– (0) phase respectively in the case of latter (123) and (iii) Lines of all cuprate compounds appear in XRD patterns of those samples preheated at temperatures 873 K. The following reaction is proposed in the case of 123 mixture: Authors are deeply thankful to the Authorities of Department of Atomic Energy (DAE), Goverment of India, for providing the funds for research project and to Professor A. V. Phadke, Department of Geology, University of Poona, for the valuable discussion.     

Arylation of aliphatic alcohols with tri-p-tolylbismuth and tri-p-tolylbismuth diacetate in the presence of a copper salt

Tri-p-tolylbismuth diacetate in the presence of a catalytic amount of a copper(II) salt (10.02, mol/mol) and tri-p-tolylbismuth in the presence of copper diacetate (1 2) replace the hydrogen atom of the hydroxyl groups of methanol and butanol with a tolyl group at 80 °C in up to 90 % yields.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 156–158, January, 1995.