Cobalt(II), Nickel(II), and Copper(II) Complexes with Diphenylthiocarbazide

New [ML(H₂O)₂] complexes (M = Co²⁺, Ni²⁺, or Cu²⁺; H₂L = diphenylthiocarbazide) were synthesized and studied using IR and diffuse reflection electronic spectroscopy, magnetic chemistry, conductometry, and DTA. The metals were shown to coordinate L^2–through nitrogen and sulfur atoms. The complex [CuL(H₂O)₂] is a dimer.     

Manganese(II), Cobalt(II), and Nickel(II) Perchlorate Complexes Containing N,O Donor Macrocyclic Ligands

Mononuclear macrocyclic complexes of manganese(II ), cobalt(II ) and nickel(II ) perchlorate using 10 different oxaazamacrocyclic ligands (L¹ — L¹⁰) have been prepared and characterized. The complexation reactions with the diiminic ligands were obtained by template condensation of the appropriate dialdehyde and diamine precursors; the reduced macrocycle complexes were synthesized using a direct route. The complexes have been characterized by elemental analyses, molar conductivity, mass spectrometry, IR, UV‐vis spectroscopy, diffuse reflectance and magnetic susceptibility measurements.     

Complexes of Cobalt(II), Nickel(II) and Copper(II) Chloroacetates with Quinoline N-Oxide

Some 1:1 and 1:2 adducts of cobalt(II), nickel(II) and copper(II) chloroacetates with quinoline N -oxide have been isolated by the interaction of the appropriate metal chloroacetate with quinoline N -oxide (QuinNo). The complexes isolated are of 1:1 stoichiometry of formula [M(CH₃_xClxCOO)₂QuinNO] (when M=Co(II), Ni(II); X=1,2 and 3 and when M=Cu(II), X=l and 2) except copper(II) trichloroacetate which yields an adduct of 1:2 stoichiometry of formula[Cu(CCI₃COO)₂(QuinNO)₂]. The adducts isolated are soluble in common organic solvents.     

Complexes of Cobalt(II), Nickel(II) and Copper(II) Chloroacetates with Quinoline N-Oxide

Some 1:1 and 1:2 adducts of cobalt(II), nickel(II) and copper(II) chloroacetates with quinoline N -oxide have been isolated by the interaction of the appropriate metal chloroacetate with quinoline N -oxide (QuinNo). The complexes isolated are of 1:1 stoichiometry of formula (M(CH_3-xCl_xCOO)₂QuinNO) (when M=Co(II), Ni(Il); X=l, 2 and 3 and when M=Cu(II), X=1 and 2) except copper(II) trichloroacetate which yields an adduct of 1:2 stoichiometry of formula[Cu(CCl₃COO)₂ (QuinNO)₃]. The adducts isolated are soluble in common organic solvents.     

N-Formamid osalicylaldimine andN-Acetamidosalicylaldimine Complexes of Copper(II), Nickel(II) and Cobalt(II)

Summary N-formamidosalicylaldimine (H₂SF) andN-acetamidosalicylaldimine (H₂SA) complexes of Cu^II, Ni^II and Co^II have been synthesized and characterized by analytical, spectroscopic and magnetic data. The ligands coordinate to the metalvia the hydroxyl, carbonyl and imino groups to yield normal paramagnetic and insoluble complexes which decompose above 250°.     

Synthesis,Characterisation and Catalytic Studies of Iron(III), Cobalt(II), Nickel(II) and Copper(II) Complexes Containing N,O Donor Ligands and Triphenylphosphine

A series of new Schiff base complexes of Fe^III, Co^II, Ni^II and Cu^II containing Ph₃P has been prepared and characterised. The Schiff bases have been prepared by the condensation of salicylaldehyde and naphthaldehyde with the appropriate aniline. The complexes have been characterised by analytical, spectral (i.r., electronic, magnetic, e.p.r., ¹H-n.m.r.) and electrochemical studies. The new complexes have been used as catalysts for aromatic coupling reactions. Higher catalytic activity has been observed for Ni^II compared to the other complexes.     

Copper(II), Nickel(II) and Cobalt(II) Complexes of Dibasic Tridentate Schiff Bases

Complexes of Cu(II), Ni(II) and Co(II) with the Schiff bases derived from o-aminobenzoic acid with salicylaldehyde and its 5-chloro and 5-bromo derivatives have been prepared. The 1:1 (metal-ligand) stoichiometry of these complexes is shown by elemental analysis, gravimetric estimations and conductometric titrations while the structures of the complexes are proved by i.r. spectra and thermogravimetric analysis. The magnetic susceptibility and electronic spectra of Cu(II) complexes indicate the nonplanar binuclear structures while that of Ni(II) and Co(II) show their paramagnetic octahedral geometry. The molar conductance values in nitrobenzene indicate the nonelectrolytic behaviour of the complexes. The results show that the complexes of the type (Cu·L)₂, Ni·L·3H₂O and Co·L·3H₂O are formed having solvent molecule in coordination with the metal ion. The monopyridine and monoammonia adducts of Cu(II) complexes were found to be monomeric.     

Synthesis and Physicochemical Study of Iron(II), Cobalt(II), Nickel(II), and Copper(II) Complexes with 4-(2-Pyridyl)-1,2,4-Triazole

New complexes of iron(II), cobalt(II), and nickel(II) with 4-(2-pyridyl)-1,2,4-triazole (PyTrz), [Fe₃(PyTrz)₈(H₂O)₄]A₆ (A = NO₃ ^-, ClO₄ ^-, Br^-) and [M₃(PyTrz)₈(H₂O)₄](NO₃)₆ (M = Co, Ni), were synthesized and studied by X-ray diffraction, magnetochemical method, and electronic and IR spectroscopy. The complex [Fe₃(PyTrz)₈(H₂O)₄](NO₃)₆) was also studied by adiabatic calorimetry. The Fe(II), Co(II), and Ni(II) nitrate complexes were shown to be isostructural to the previously synthesized linear trinuclear [Cu₃(PyTrz)₈H₂O)₄](NO₃)₆ complex. In all compounds, antiferromagnetic exchange interactions between M²⁺ ions were detected. The complex [Fe₃(PyTrz)₈(H₂O)₄](NO₃)₆ undergoes the ¹ A ₁ ⁵ T ₂ spin transition.     

A Thermodynamic Study Of N,N,N',N'-Tetrakis(2-Hydroxyethyl)-Ethylenediamine Complexes With Nickel(II), Copper(II), And Zinc (II)

Abstract

Thermodynamic parameters have been determined by poten-tiometric techniques for complex ions formed by N,N,N',N'-tetrakis(2-hydroxyethyl)ethylenediamine TKED, with nickel (II), copper(II), and zinc(II) ions. The formation constants, enthalpy, and free energy data for the complexes exhibited values qualitatively consistent with predicted ligand field stabilization trends for these cations. The general expected stability of the complexes in the order Ni(II) < Cu(II) > Zn(II) is observed.     

四碘代对苯二甲酸根桥联的双钴(II)配合物的研究

报导了四种新的双核钴（Ⅱ）配合物，即［Co2（4I-TPHA）（L）4］（COl4）（4I-TPHA＝四碘代对苯二甲酸根阴离子，L＝1，10菲咯啉（phen）（1），5-硝基-,10菲咯啉（NO2-phen）（2），2，2′-联吡啶（bpy）（3）和4，4′-二甲基-2，2′-联吡啶（Me2bpy）（4）的合成和表征，配合物的磁性研究表明双核钴（Ⅱ）离子间有弱的反铁磁性自旋交换相互作用。     

Synthesis and Characterization of Two New Schiff Base Ligands and their Complexes with Cobalt(II), Nickel(II) and Copper(II)

Two Schiff base ligands, 2-{E-[(5-phenyl-6H-1,3,4-thiadiazin-2yl)imino]methyne}-1-naphthol (L¹H) and 5-nitro-2-{[(5-phenyl-6H-1,3,4-thiadiazin-2-yl)imino]methyne}phenol (L²H) have been prepared from 5-phenyl-6H-1,3,4-thiadiazin-2-amine (A), 2-hydroxynaphthaldehyde (1) and 2-hydroxy-5-nitrobenzaldehyde (2) Mononuclear Co(II), Ni^II and Cu^II complexes of the ligands have been prepared by using Co^II, Ni^II and Cu^II salts with a 1:2 metal:ligand ratio. It was determined that the bidentate behavior of the ligands is accomplished via the phenolic oxygen and the azomethine nitrogen atoms. The structures of the ligands and their complexes were identified by using elemental analyses, i.r., ¹H-n.m.r. spectra, electronic spectra, magnetic susceptibility measurements and thermogravimetric analyses (t.g.a.).     

Novel Cobalt(II), Nickel(II) and Copper(II) Complexes of Neutral Orotic Acid. Synthesis,Spectroscopic and Thermal Studies

The new orotic acid complexes, [MCl₂(H₂O)₃(H₃Or)], M=Co(II), Ni(II) and [CuCl₂(H₂O)(H₃Or)₃] · H₂O, were synthesized and characterized by elemental analysis, magnetic susceptibility, spectral (Diffuse reflectance UV–Vis and FTIR) methods, and simultaneous thermal analysis (TG, DTG and DTA) techniques. Physical measurements indicate that the neutral orotic acid ligands are bonded to metal ions through the carbonyl groups. Two thermal processes of the complexes can occur: dehydration and pyrolytic decomposition. On the basis of the DTG_max, the thermal stability of the complexes follows the order: Co(II) (122 °C) > Cu(II) (77 °C) > Ni(II) (66 °C).     

Thermal Studies of Cobalt(II), Nickel(II) and Copper(II) Complexes of 4-(Sulfonylazido Phenylazo) Pyrazolones

The thermal decompositions of cobalt(II), nickel(II) and copper(II) complexes of4-(3'-sulfonylazido-6'-methoxyphenylazo)-1-phenyl-3-methyl-2-pyrazolin-5-one H(D¹–SO₂N₃) and 4-(4'-sulfonylazido phenylazo)-3-phenyl-3-methyl-2-pyrazolin-5-one H(D²–SO₂N₃) were studied by thermogravimetry. The decomposition in all cases takes place along two stages. The first stage is due to the elimination of water and nitrogen molecules with the formation of tetracoordinate complexes containing nitrene reactive species[M(DSO₂N:)₂]. The second stage represents the decomposition of the material to the metal oxide. The kinetics of the decomposition were examined by using Coats–Redfern, the decomposition in all complexes was found to be first order for the first and second stages. The activation energies and other activation parameters (H^* and S^* and G^*) were computed and related to the bonding and stereochemistry of the complexes.This revised version was published online in November 2005 with corrections to the Cover Date.     

Synthesis and Characterization of Mononuclear Cobalt(II), Nickel(II), Copper(II), Zinc(II), Cadmium(II) and Dinuclear Uranyl(VI) Complexes with N,N-bis(2-{[(2,2-dimethyl-1,3-dioxolan-4-yl)methyl]amino}butyl) N′,N′-dihydroxyethanediimidamide

In this study, the new vic-dioxime ligand (LH₂) and its complexes with Co^II, Ni^II, Cu^II, Zn^II, Cd^II and UO₂^VI are described. The structures of these complexes were characterized by elemental analyses, i.r., ¹H- and ¹³C-n.m.r. spectra, u.v.–vis. spectroscopy, magnetic susceptibility measurements, conductivity measurements and thermogravimetric analyses (t.g.a.).     

Binuclear Nickel(II) and Cobalt(III) Complexes with Dissimilar Bridges: Synthesis,Spectroscopy, Crystal Structure,and Magnetism

Two novel binuclear nickel(II) and cobalt(III) complexes with two or three dissimilar bridges, [Ni₂(tacn)₂(μ‐N₃)₂(μ‐O₂CPh)](ClO₄)?H₂O ( 1 ) and [Co₂(tacn)₂(μ‐N₃)(μ‐OH)(μ‐O₂CPh)](ClO₄)₃ ( 2 ) (tacn=1,4,7‐triazacyclononane), were synthesized and structurally as well as magnetically characterized. Both compounds have a discrete binuclear structure, bridged by two N₃^? ions and one carboxylato group of the benzoate ion for 1 and one N₃^? ion, one carboxylato group of the benzoate ion, and one hydroxy group for 2 ; the macrocyclic ligand tacn acts as terminal ligand. The magnetic data of compound 1 were analyzed by means of ? = ?2J?₁?₂?D(?₁²+?₂²), leading to J = 19.6 cm^?1, g=2.07, D = 4.01 cm^?1, and zJ′ = 0.32 cm^?1. The ferromagnetic interaction is discussed on the basis of the structural features.     

Syntheses,Structures, and Properties of Copper(II), Cobalt(II), and Cadmium(II) Complexes with Flexible Multicarboxylate Ligand

Three new coordination polymers, namely, [CuL_0.5] ( 1 ), [Co(H₂L)(H₂O)₂][H₂O] ( 2 ), and [(CdCl)_0.5Cd_0.25(H₂L)_0.5] ( 3 ) were synthesized under hydrothermal conditions from the corresponding Cu^II, Co^II, and Cd^II salts with a multidentate ligand of 2,2′,2′′,2′′′‐[2,3,5,6‐tetramethyl‐1,4‐phenylenebis(methylenenitrilo)]tetraacetic acid (H₄L). The complexes were characterized by single‐crystal X‐ray diffraction, IR, thermogravimetric, and elemental analyses. Complex 1 crystallizes in the orthorhombic space group Pbca and has a three‐dimensional architecture with infinite two‐dimensional networks linked together by weak Cu–O interactions. Complex 2 crystallizes in the monoclinic space group P2(1) and displays a 2D network. Complex 3 crystallizes in the tetragonal space group P4(2)/ncm and exhibits an infinite 3D architecture that has unusual [Cd₂(CO₂)₄Cl₂] dinuclear paddle‐wheel units and [Cd(CO₂)₄] dodecahedron units. The results showed that the coordination arrangement of central metal atoms and the conformation and coordination mode of organic ligands play an important role in determining the structure of the complexes. The luminescence property of complex 3 was studied in the solid state at room temperature.     

Zinc(II), Cobalt(II) and Nickel(II) Complexes of 5-Substituted-1,3,4-Thiadiazoles

Zn(II), Co(II) and Ni(II) complexes with some 5-substituted-1,3,4-thiadiazoles (L₁-L₄) have been prepared and characterized by conductivity, microanalysis, thermal analysis, infrared and electronic spectra measurements. All complexes behave as 1:1 electrolyte and the ligands are coordinated as bidentate molecules. The stability constants and energy of formation are determined and discussed on the basis of the ligands structure.     

The Liquid-Liquid Extraction of Copper(II), Nickel(II), and Cobalt(II) with 2,2′-Pyridil-mono-(2-quinolylhydrazone)

A 1:1 synthesis of 2-quinolylhydrazine with 2,2′-pyridil yields the hydrazone 2,2′-pyridil-mono-(2-quinolylhydrazone). In either the Z or E isomeric configuration, the molecule can serve as a tridentate ligand. Equilibrium studies were carried out to determine the effects of pH and concentration of ligand and metal on the distribution of the extracted complex into methyl isobutyl ketone. Graphical analysis of the slopes of the plot of the logarithm of the distribution coefficient vs pH, log [ligand], and log [M(II)] will determine the stoichiometry and polymerization of the complex. In the extraction of Cu(II), Ni(II), and Co(II), there is a small change in log D, where D is the distribution coefficient, with pH indicating the presence of a weakly dissociated ligand. Ligand:metal (1:1) ion-paired species are extracted, each having three absorption peaks in the region 400-550 nm. While a spectrophotometrtc method for each element does not seem feasible due to simultaneous extraction and overlapping absorbances, an extractive-atomic absorption method for the analysis of 1.6 ppm of Cu(II) is presented. Excesses of 20-70 ppm Co(II), Zn(II), Cd(II), Cl⁻, NO₃⁻, and SO₄²⁻ do not interfere.     

Spectrophotometric Determination of Cobalt(II), Nickel(II) and Copper(II) with Acenaphthenequinone Monosemicarbazone (AQSC)

Cobalt(II), nickel(II) and copper(II) complexation with acenaphthenequinone monosemicarbazone (AQSC) has been studied spectrophotometrically. The Co(II), Ni(II) and Cu(II) complexes are soluble in ethanol medium and exhibit maximum absorbance at 410, 420 and 430 nm, respectively. The sensitivity of the reactions are 0.012, 0.02 and 0.01 μg/cm² for cobalt, nickel and copper systems. All the three complexes show maximum and constant absorbance in the pH range 8.4 to 9.8, 6.3 to 8.4 and 5.4 to 8.0 for Co-AQSC, Ni-AQSC and Cu-AQSC, respectively. Nickel and copper in some alloys have also been analysed.