Complex compounds of Cu(II) and Zn(II) withN,N-dimethylglycine andN,N-diethylglycine in water and in water—Methanol system

The complex equilibria of the systems: copper—N,N-dimethylglycine, zinc—N,N-dimethylglycine, copper—N,N-diethylglycine, and zinc—N,N-diethylglycine have been studied by computer analysis of potentiometric data. The stability constants of the complexes formed in these systems are reported. A discussion is presented about the influence of the substituent and the solvent on the dissociation constants of the amino acids and the stability constants of their complexes with metals.¹H NMR and IR studies indicate that both functional group of the ligands are involved in complex formation.

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Cu(II)- und Zn(II)-Komplexe mitN,N-Dimethylglycin undN,N-Diethylglycin in Wasser und Wasser—Methanol-Lösung

Zusammenfassung Anhand der Computer-Analyse von potentiometrischen Daten wurden die Bildungsgleichgewichte von Kupfer(II)- und Zink(II)-Komplexen mitN,N-Dimethylglycin undN,N-Diethylglycin untersucht. Die Beständigkeitskonstanten der gebildeten Komplexe wurden angegeben. Der Einfluß von Liganden und Lösungsmitteln auf Beständigkeit und Dissoziationskonstanten dieser Komplexe wurde diskutiert. Es wurde mittels¹H-NMR- und IR-Untersuchungen festgestellt, daß bei der Bildung der Komplexe beide funktionellen Gruppen der Liganden teilnehmen.

     

Ni(II)/N,N-dimethylglycine complex equilibrium study

The complex formation of Ni(II) withN,N-dimethyl-glycine in water and in water-methanol has been studied by computer analysis of potentiometric data.

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Gleichgewichtsuntersuchungen der Komplexbildung von Ni(II) mitN,N-Dimethylglycin (Kurze Mitteilung)

Zusammenfassung Anhand der Computer-Analyse von potentiometrischen Daten wurden die Bildungsgleichgewichte von Nickel(II)-Komplexen mitN,N-Dimethylglycin in Wasser und Wasser — Methanol untersucht.

     

Studies on the complex formation between lactams and thiolactams of sparteine with copper(II) cation

The complex formation for lactams and thiolactams of sparteine with Cu(II) cation in ethanol was studied by theoretical, kinetic and MS methods. The studied compounds with Cu(II) cation formed 1:1 and 1:2 complexes. The kinetic parameters of their formation were determined. Both kinetic and thermodynamic parameters depend strongly on the presence of oxo- or thiono-group in sparteine skeleton.     

X-Ray and EPR study on copper (II) complexes with an enamine ligand

The enamine (HEAID) obtained from aniline and 2-acetyl-1,3-indandione (2AID) behaves as a bidentate ligand in coordination with copper (II) ion. Two types of crystals, apparently different in shape, were isolated and studied by single-crystal X-ray diffraction. The X-ray data for the brown rhombic crystals of compound 1 shows a mononuclear complex of Cu(II) coordinated with two EAID-anions, Cu(EAID)₂. The X-ray data for the green crystals of compound 2 shows a dinuclear Cu(II) complex with two OH⁻ groups acting as bridging ligands, [Cu₂(μ-OH)₂(EAID)₂]. In both cases the ligand coordinates after deprotonation of the amine group.     

Nickel(II), copper(II) and zinc(II) complexes withN-phenylglycine in water-methanol solution

The complex equilibria of the Ni(II), Cu(II), and Zn(II) complexes withN-phenylglycine have been studied by computer analysis of potentiometric data. The mode of coordination has been established by¹H NMR and IR studies.

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Nickel(II), Kupfer(II) und Zink(II)-Komplexe mitN-Phenylglycin in Wasser-Methanol-Lösung

Zusammenfassung Anhand der Computer-Analyse von potentiometrischen Daten wurden die Bildungsgleichgewichte von Nickel(II), Kupfer(II) und Zinc(II)-Komplexen mitN-Phenylglycin untersucht. Zur Bestätigung des Koordinationstyps wurden¹H-NMR- und IR-Messungen vorgenommen.

     

Synthesis and structural studies of Co(II) and Ni(II) complexes of glutaric- and adipic dihydrazides

Glutaric dihydrazide (GDH) and adipic dihydrazide (ADH) have been found to react with Co(II) chloride and Ni(II) chloride and nitrate in ethanolic solution to form complexes of the general empirical compositionsMLCl₂,ML ₂Cl₂ and [NiL ₂(H₂O)₂] (NO₃)₂ whereM=Co(II), Ni(II) andL=GDH,ADH. Tetrahedral geometry has been proposed for 11 complexes of Co(II) and octahedral geometry for the remaining complexes based on measurements of molar conductance, magnetic susceptibility, electronic and ir spectra.

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Synthese und Struktur von Co(II)- und Ni(II)-Komplexen von Glutarsäure- und Adipinsäuredihydraziden

Zusammenfassung Glutarsäuredihydrazid (GDH) und Adipinsäuredihydrazid (ADH) bilden mit Co(II)-Chlorid und Ni(II)-Chlorid bzw.-Nitrat in ethanolischer Lösung Komplexe der generellen ZusammensetzungenMLCl₂,ML ₂Cl₂ und [NiL(H₂O)₂] (NO₃)₂, mitM=Co(II), Ni(II) undL=GDH,ADH. Für 11-Komplexe von Co(II) wird eine tetragonale Geometrie, für alle anderen Komplexe eine oktaedrische Geometrie vorgeschlagen. Die Basis dazu lieferten Messungen der molaren Leitfähigkeit, der magnetischen Suszeptibilität und der UV- bzw. IR-Spektren.

     

Three new coordination complexes of cobalt(III), manganese(II), and copper(II) with N,N,O-donor hydrazone ligands: syntheses and structural characterizations

Three new coordination complexes, 2{[Co(L¹)₂]ClO₄} · 0.5CH₃OH (1), [Mn(L²)₂] (2), and [Cu(HL²)(L²)]ClO₄ · 2H₂O (3) have been synthesized from two tridentate N,N,O-donor hydrazone ligands HL¹, 2-acetylpyridine-salicyloylhydrazone, and HL², 2-benzoylpyridine-salicyloylhydrazone, respectively and thoroughly characterized by elemental analysis, FT-IR, UV–Vis, electrochemical, and room temperature magnetic susceptibility measurements. Structures of the complexes have been unequivocally established by single crystal X-ray diffraction technique. Structural analysis reveals that 1 consists of two chemically similar but crystallographically independent cationic [Co(L¹)₂]⁺ units and 2 consists of a neutral [Mn(L²)₂] molecule while 3 consists of a cationic [Cu(HL²)(L²)]⁺ unit. Metal ions display distorted octahedral geometry in 1 and 2 while in 3 it shows a distorted square pyramidal geometry. Ligand conformations around the metal ions are stabilized by the presence of intra-ligand hydrogen bonding in all the complexes. Structure of 3 reveals that a perchlorate ion linked to the complex by hydrogen bonding via a water molecule.     

Synthesis,structure, electrochemical properties,and antioxidant activities of copper(II) and zinc(II) complexes with N,N-bis(N-ethyl-2-ylmethylbenzimidazol)allylamine ligand

N,N-bis(N-methyl-2-ylmethylbenzimidazole)aniline (EtAIDB) and its transition metal complexes, [Cu(EtAIDB)Br₂]·EtOH {dibromo[N,N-bis(N-methyl-2-ylmethylbenzimidazole)aniline] copper(II) ethanol} (1) and [Zn(EtAIDB)Br₂] {dibromo[N,N-bis(N-methyl-2-ylmethylbenzimidazole)aniline] zinc(II)} (2), have been synthesized and characterized by elemental analysis, molar conductivity, UV–visible, and IR spectroscopy. The X-ray crystallographic studies of 1 and 2 have shown two different arrangements: 1 is distorted square-based pyramidal, while 2 can be treated as distorted tetrahedral. The cyclic voltammogram of 1 represents quasi-reversible Cu²⁺/Cu⁺ pairs. In vitro antioxidant tests showed that 1 had significant antioxidant activity against superoxide and hydroxy radicals.     

Complex formation of copper(II) and nickel(II) with N-arylthiopicolinamides

The reactions of N-arylthiopicolinamides (HL) with copper(II) and nickel(II) ions in organic and aqueous-organic solutions were studied. On addition of HCl, the transformation of ML₂ complexes into M(HL)Cl₂ occurs, while the reverse reaction takes place under the action of amphoteric protic solvents. The structures of the isolated complexes were established by IR and UV spectroscopy.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1546–1550, September, 1993.     

Studies on nickel(II) complexes of N-aryl thioureas

The preparation and properties of the crystalline compounds of the type NiL ₄Cl₂, NiL ₂Cl₂ and NiLCl₂ (L=N-aryl thioureas) are described. Analytical, conductometric, magnetic and spectral data (infrared and electronic)_show that complexes of the type NiL ₄Cl₂ possess octahedral structure and those of NiL ₂Cl₂ and NiLCl₂ are characterised as distorted octahedral in solid state. The ligand field parametersD _q ,B and calculated from electronic spectral data, suggest a weak field for all the ligands. Metal sulphur bonding for all ligands is adduced from infrared and far infrared spectral studies.

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Untersuchungen an Nickel(II) Komplexen von N-Aryl-thioharnstoff Derivaten

Zusammenfassung Darstellung und Eigenschaften der kristallinen Verbindungen vom Typ NiL ₄Cl₂, NiL ₂Cl₂ und NiLCl₂ (L=N-Arylthioharnstoff) werden beschrieben. Magnetische Eigenschaften, Leitfähigkeitsmessungen, analytische und spektroskopische Daten beweisen, daß die Komplexe vom Typ NiL ₄Cl₂ oktaedrische Struktur besitzen; die Komplexe vom Typ NiL ₂Cl₂ und NiLCL₂ weisen eine verzerrt oktaedrische Geometrie auf. Die Ligandenfeld-ParameterD _q ,B und , die aus Elektronenanregungsspektren berechnet wurden, zeigen ein schwaches Feld für alle untersuchten Liganden an Aus Untersuchungen der Spektren des IR und fernen IR folgt, daß die Komplexe eine Metall—Schwefel-Bindung aufweisen.

     

A calorimetric study ofN,N-dimethylformamide complexes of copper(II) in acetonitrile

Complex formation of copper(II) with N,N-dimethylformamide(DMF) has been investigated calorimetrically in acetonitrile at 25°C. Calorimetric titration curves obtained are explained in terms of formation of [Cu(dmf) _n ]²⁺ (n=1–4, 6) and their formation constants, enthalpies and entropies were determined. Formation of [Cu(dmf)₅]²⁺ is uncertain. The stepwise enthalpies S ₃ ⁰ and entropies S _n ⁰ at each consecutive step are all negative except for S ₃ ⁰ . The overall enthalpies of formation of [Cu(dmf)₆]²⁺ is –(77.8±5.4) kJ-mol^–1, which is compared with the enthalpy of transfer of copper(II) ion, H _t ^o =–79.7 kJ-mol^–1, from acetonitrile to DMF.     

Darstellung und Charakterisierung von Halogeno(diethyldithiocarbamato) (triethyl- und triphenylphosphin)palladium(II)-Komplexen

The Complexes [Pd(PEt ₃)₂ dtc]X (1) and Pd(PR ₃)Xdtc (2, 3) (dtc=S₂CNEt ₃;X=Cl, Br, I;R=Et, Ph) have been prepared. Conductivity, susceptibility, UV and IR measurements show that the cations [Pd(PEt ₃)₂ dtc]⁺ of1 and the complexes2, 3 have square-planar structure.

     

Comparative EPR study of copper(II) complexes with threonine derivatives

Summary In order to get better insight into the structural reasons for different properties of copper(II) complexes withL-threonine,L-allo-threonine,L-N,N-dimethyl-threonine, andL-N,N-dimethyl-allo-threonine, their EPR spectra were studied as a function ofpH and temperature. AtpD9.4, in all complexes a change in the copper(II) coordination sphere from the glycine to the hydroxy type was observed. Inbis(L-threoninato)copper(II), the hydroxy type formed atpD9.4 was found to be stablized by increasing the temperature of the solution from 280 to 320 K. In all other copper(II) complexes, the conformational change is accompanied by the disruption of the Cu-N bond of one chelate ring.

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Vergleichende EPR-Untersuchungen von Kupfer(II)-Threonin-Komplexen

Zuzammenfassung Um einen besseren Einblick in die Beziehungen zwischen Struktur und Eigenschaften von Kupfer(II)-Komplexen mitL-Threonin,L-allo-Threonin,L-N,N-Dimethyl-Threonin undL-N,N-Dimethyl-allo-Threonin zu gewinnen, wurden ihre EPR-Spektren in Abhängigkeit vompH-Wert und von der Temperatur untersucht. Bei einempH-Wert von 9.4 (in deuterierter Lösung) wurde eine Veränderung in der Kupfer (II)-Koordinationssphäre festgestellt, die von einer Glycin-ähnlichen Konformation in eine vermutlich Hydroxy-ähnliche Konformation übergeht. Derbis(L-Threoninato)-Kupfer (II)-Hydroxy-Komplex wird durch eine Temperaturerhöhung von 280 auf 320K stabilisiert. Die Veränderung der Koordination vom Glycin-Typ wird von einem Bruch der Cu-N-Bindung eines Chelatrings begleitet.

     

Thermally induced oxidative trimerization of benzimidazole by copper(II) chloride in the solid state

Benzimidazolium trichlorocuprate(II) undergoes a redox reaction in the solid state at elevated temperature (∼240°C) to produce the cyclic trimer of benzimidazole and cuprous chloride. The trimer has been characterized by IR, NMR, and Mass spectroscopy. It has also been synthesized in lower yield by heating the mixtures of CuCl₂ and benzimidazole in different ratios or heating other compounds of CuCl₂ and benzimidazole. The absorption, emission, and excitation spectra of the trimer in two different solvents (TFA and DMSO) and a comparison of these results with those of benzimidazole are presented here.     

A study of complex equilibria of phenylglycine with nickel(II), copper(II) and zinc(II) in water and in water - methanol solution

The complex equilibria of the systems phenylglycine — nickel(II), copper(II) and zinc(II) in water and in water — methanol solution have been studied by computer analysis of potentiometric data. The mode of coordination has been established by¹³C-NMR and IR studies.

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Gleichgewichtsuntersuchungen der Komplexbildung von Phenylglycin mit Nickel(II), Kupfer(II) und Zink(II) in Wasser und Wasser - Methanol-Lösung

Zusammenfassung Anhand einer Computer-Analyse von potentiometrischen Daten wurden die Bildungsgleichgewichte in den Systemen Phenylglycin — Nickel(II), Kupfer(II) und Zink(II) untersucht. Der Koordinationstyp wurde mittels¹³C-NMR und IR festgestellt. Die Lösungsmittel waren Wasser und Wasser — Methanol.

     

Biosorption of copper(II) and cadmium(II) by a novel exopolysaccharide secreted from deep-sea mesophilic bacterium

The biosorption behaviors and mechanisms of a novel exopolysaccharide (EPS), which is secreted by a mesophilic bacterium (namely Wangia profunda (SM-A87)) isolated from deep-sea sediment, for heavy metals Cu(II) and Cd(II) have been studied in this paper. The effects of SM-A87 EPS concentration, solution pH and ionic strength on the metal uptake were investigated by employing batch adsorption techniques, respectively. The optimum biosorption capacities were observed at pH 5.0 for Cu(II) with 48.0 mg/g and pH 6.0 for Cd(II) with 39.75 mg/g, respectively. Addition of salts decreased Cu(II) or Cd(II) uptake in the order of K⁺ < Na⁺ < Ca²⁺. Langmuir and Freundlich models were employed to describe the biosorption equilibrium data, indicating the favorable biosorption occurs and larger biosorption capacity and intensity for Cu(II) than for Cd(II). The biosorption kinetics for both metals can be well described by pseudo-second-order kinetic model, compared with pseudo-first-order and intraparticle diffusion kinetic models. The competitive biosorption was also studied, indicating that in two-component solution with different metal ratios, the selective biosorption of SM-A87 EPS for Cu(II) was much higher than for Cd(II). The Fourier transform infrared spectroscopy (FT-IR) analysis indicated possible functional groups (e.g., OH, COO and COC) of SM-A87 EPS involved in metal biosorption process, which indicated the potential of using SM-A87 EPS as an effective sorbent for Cu(II) or Cd(II) removal from water.     

EPR study on the charge-transfer photochemistry of the bromide mixed-ligand dithiocarbamate complex of copper(II)

The EPR technique has been used to study the photolysis of the mixed-ligand complex Cu^II(Et₂dtc)Br in a 1:1 solvent mixture of chloroalkane and alcohol, where the chloroalkane is CCl₄, CHCl₃ or CH₂Cl₂ and the alcohol is MeOH, EtOH, i-PrOH or i-BuOH, in comparison with Cu^II(Et₂dtc)Cl photolysis in CHBr₃:ROH. It was found that while Cu^II(Et₂dtc)Br photolysis in chloroalkane:ROH yielded Cu^II(Et₂dtc)Cl as an intermediate, the opposite conversion of Cu^II(Et₂dtc)Cl to Cu^II(Et₂dtc)Br proceeded via Cu^II(Et₂dtc)Cl photolysis in CHBr₃:ROH. The final photolytic products in both cases were tetraethylthiuramdisulphide and the corresponding copper(II) salt (CuCl₂ or CuBr₂, respectively). The results obtained by EPR allowed to get some insight into the behaviour of the primary photolytic products towards both components of the mixed solvent.     

Coordination behavior of 3,4-bis(2-pyridylmethylthio)toluene with copper(II) ions: Synthesis,structural characterization and reactivity,and DNA binding study of the dinuclear copper(II) complex

On reaction of different copper(II) salts with 3,4-bis(2-pyridylmethylthio)toluene (L) having neutral tetradentate NSSN donor set in different chemical environments, two mononuclear copper(II), one dinuclear copper(I) and one dinuclear copper(II) complexes, formulated as [Cu^II(L)(H₂O)₂](NO₃)₂ (1), [Cu^II(pic)₂] (2), [Cu^I₂(L)₂](ClO₄)₂ (3) and [Cu^II₂(L)₂Cl₂](ClO₄)₂ (4), respectively, were isolated in pure form [where pic = picolinate]. All the complexes were characterized by physicochemical and spectroscopic methods. The product of the reactions are dependent on the counter anion of copper(II) salts used as reactant and on the reaction medium. Complexes 1 and 4 were obtained with nitrate and perchlorate copper(II) salts, respectively. On the other hand, C–S bond cleavage was observed in the reaction of L with copper(II) chloride to form in situ picolinic acid and complex 2. Dinuclear complexes 3 and 4 were separated out when copper(II) perchlorate was allowed to react with L in methanol and in acetonitrile, respectively, under aerobic condition. The X-ray diffraction analysis of the dinuclear complex 3 shows a highly distorted tetrahedral geometry about each copper ion. Complex 4 is converted to 3 in acetonitrile in presence of catechol. The spectral study of complex 4 with calf thymus DNA is indicative of a groove binding mode interaction.