Thermal investigation of cobalt, nickel and copper complexes with 8-aminoquinoline

Complexes of Co(II), Ni(II) and Cu(II) with 8-aminoquinoline were prepared and characterized, and their thermal behaviour and decomposition pathways were studied. The thermal stabilities are discussed in terms of ionic radii, crystal field splitting energy and steric hindrance. The effective roles of the counter-ions (Cl^? and NO ₃ ^? ) on the decomposition temperatures and the final products were also clarified. The energies of activation (E _a ) and the orders of some decomposition reactions were determined. Light is shed on the nature of the interaction of the water of crystallization and the polymorphic transformation phenomenon.     

Preparation of cobalt and nickel complexes of 8-hydroxyquinoline with nanobelt structure via one-step,low-heating,solid-state reactions

Two nano-structural complexes, bis-(8-hydroxyquinoline) cobalt and bis-(8-hydroxyquinoline) nickel, have been prepared by one-step, low-heating, solid-state reaction, a simple, safe, economical and environmentally-friendly method. TEM and SEM images show that the complexes are composed of nanobelts with width ranging from 100 to 300?nm and a length of up to 1?µm. The technique offers a new way for fabricating coordination compounds with one-dimensional nanostructure.     

Thermal decomposition of nicotinate complexes of cobalt and nickel in dynamic nitrogen atmosphere

Thermal decomposition of cobalt and nickel nicotinate was studied by TG, DTG and DSC. The mechanism of decomposition has been established from TG and DSC data. The kinetic parameters namelyE, A together with ΔH were calculated from DSC curves using mechanistic and non-mechanistic integral equations.

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Zusammenfassung Mittels TG, DTG und DSC wurde die thermische Zersetzung von Cobaltund Nickelnikotinat untersucht. Der Zersetzungsmechanismus wurde anhand der TG-und DSC-Daten entwickelt. Die kinetischen ParameterE, A wurden zusammen mit ΔH anhand der DSC-Kurven mit Hilfe von mechanistischen und nichtmechanistischen Integrationsgleichungen berechnet.

     

Solvent extraction of cobalt and nickel with 5,7-dichloro-2-methyl-8-hydroxyquinoline into chloroform

Summary The distribution equilibria of the cobalt and nickel complexes with 5,7-dichloro-2-methyl-8-hydroxyquinoline in the water-chloroform system have been studied. The influence of pH, reagent and metal concentrations, and the presence of NaClO₄ or Na₂SO₄ in the aqueous phase has been studied. From slope analysis of the distribution curves the compositions of the extracted species have been determined. The cobalt complexes extracted are [Co₂R₃(RH)]ClO₄, [Co₂R₃(RH)₃]ClO₄ and Co₂R₄; in all of them the metal is in oxidation state Co(II). For nickel the NiR₂ and NiR₂(RH) complexes are extracted.

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Die Extraktion von Kobalt und Nickel mit 5,7-Dichlor-2-methyl-8-hydroxychinolin in Chloroform

Zusammenfassung Die Verteilung der Kobaltund Nickel-Komplexe mit 5,7-Dichlor-2-methyl-8-hydroxychinolin in dem System Wasser-Chloroform wurde untersucht. Auch der Einfluß des pH, der Reagensund Metallkonzentration und der Anwesenheit von NaClO₄ oder Na₂SO₄ in der wäßrigen Phase auf das Verteilungsgleichgewicht wurde geprüft. Aus der Lage der Verteilungskurven wurde die Zusammensetzung der extrahierten Substanzen bestimmt. Die extrahierten Kobaltverbindungen waren [Co₂R₃(RH)]ClO₄, [Co_{2R 3}(RH)₃]ClO₄ und Co₂R₄; diese enthalten alle Co(II). Im Falle des Nickels wurden die Verbindungen NiR₂ und NiR₂(RH) beobachtet.

     

Thermal decomposition of nickel aluminium mixed hydroxides and formation of nickel aluminate spinel

Various nickel aluminium mixed hydroxide samples of different compositions were prepared by co-precipitation from their nitrate solutions using dilute NH₄OH. Additional samples were prepared by impregnation of hydrated Al₂O₃, preheated at 600 and 900°C, with nickel nitrate solution in an equimolar ratio. The thermal decomposition of different mixed solids was studied using DTA. The X-ray investigation of thermal products of the mixed solids was also studied.The results obtained revealed that the presence of NiO up to 33.3 mole % with aluminium oxide much enhanced the degree of crystallinity of the γ-Al₂O₃ phase. In contrast, the presence of Al₂O₃ much retarded the crystallization process of the NiO phase. With the exception of samples containing 20 mole% NiO, all the mixed hydroxide samples, when heated in air at 900°C, led to the formation of well-crystalline Ni Al₂O₄ spinel, alone, or together with either NiO or γ-Al₂O₃, depending on the composition of the mixed oxide samples. The solid containing 20% NiO and heated at 900°C was constituted of amorphous NiO dispersed in γ-Al₂O₃. Heating the nickel nitrate-impregnated Al₂O₃ in air at 800–1000°C led to the formation of Ni Al₂O₄ together with non-reacted NiO and γ-Al₂O₃. The degree of crystallinity of the spinel was found to increase by increasing the calcination temperature of the impregnated solids from 800 to 1000°C and by increasing the preheating temperature of the hydrated Al₂O₃ employed from 600 to 900°C.     

Thermal analysis of cobalt,nickel and copper complexes of 2-aminothiazole

The thermal decomposition of 2-aminothiazole (2-amt) complexes of general formula M(2-amt)₂X₂ [M = Co(II) and Cu(II)] and Ni(2-amt)₄X₂ [X = Cl and Br] have been studied in air and argon by TG and DTG as well as by DTA in nitrogen; end products from the decompositions in air have been characterised by X-ray powder diffraction. Decomposition stoichiometries have been proposed and factors governing the thermal decomposition have been discussed.     

High-performance liquid chromatography of 8-hydroxyquinoline chelates of aluminium and cobalt(III)

Summary The 8-hydroxyquinoline chelates of Co(III) and Al(III) may be separated by high-performance liquid chromatography using a silica column and 5% methanol in chloroform as mobile phase. Using detection at 254 nm, the method provided detection limits of 0.9 ng of Co(III) and 17 ng of Al(III) in a 10 mm³ injection.     

Paramagnetic shifts in complexes of N-vinylimidazole with manganese,iron, cobalt,nickel, and copper chlorides

The observed paramagnetic shifts and broadenings of the resonance lines in the PMR spectrum of N-vinylimidazole upon the addition of its complexes with manganese, iron, cobalt, nickel, and copper chlorides are compared.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 994–995, July, 1972.We thank Doctor of Chemical Sciences Yu. N. Molin for his assistance in carrying out this investigation.     

Synthesis and characterization of divalent manganese,cobalt, nickel,copper and zinc complexes with nicotinic acid

Coordination compounds of the transition metal(II) acetylacetonates of the formula [M(NA)₂(acac)₂ ]_n (M = Mn, Co, Ni, Cu and Zn; NA = nicotinic acid and acac = acetyl-acetonate anion) have been synthesized and characterized by chemical analysis, magnetic susceptibility, ligand-field spectra, IR and far-IR spectral measurements as well as photoacoustic spectroscopy in the solid state. Tentative stereochemistries for the complexes isolated in the solid state are suggested. The ligand-field parameters 10 Dq, B, β, λ and CFSE are calculated for cobalt and nickel complexes and are in good agreement with the proposed geometries. The metal ions attain six-coordination through the four oxygens of the anion and two donor atoms of the nicotinic acid ligands acting always as monodentate ligands. The formation of the compound results in a considerable shift of v(M-O) to lower frequencies in all the compounds related to parent acetylacetonates.     

Thermal behaviour of 8-hydroxyquinoline complexes with nickel(II)/copper(II)/zinc(II) hydroxides

Thermal behaviour of M(OH)₂(8-HQ)₂ (M=Ni, Cu and Zn; 8-HQ=8-hydroxyquinoline) has been studied by dynamic TG and DTA methods in nitrogen atmosphere. The percent weights lost in different temperature range was calculated from TG curves. The mode of decomposition has been supported by endotherms observed in DTA curves of the respective compounds.     

Iron,cobalt and nickel violurate complexes

Summary The Fe^II, Fe^III, Co^II, Co^III and Ni^II violurates have been synthesised and their electronic spectra (in Nujol mulls and dimethyl formamide), i.r. spectra, magnetic properties, molar conductivity, differential thermal analysis (d.t.a.), thermogravimetric analysis (t.g.a.), elemental analysis, m.p., specific gravity and solubility have been recorded. The structures of the complexes have been inferred from magnetic and spectral data.     

Formation of nickel, cobalt, manganese and cadmium ferrocyanides

Potentiometric and solubility studies have been made of the ferrocyanides of nickel, cobalt, manganese(II) and cadmium both in the presence and absence of potassium. The K(3p),DeltaG degrees , DeltaH degrees and DeltaS degrees values are reported.     

Thermal and structural studies of the chloro complexes of cobalt,nickel and copper with 3-phenylpyridine

The chloro complexes of cobalt, nickel and copper with 3-phenylpyridine were prepared in ethanolic solution from which solid compounds were isolated. The cobalt and copper complexes have stoichiometry M₂LCl₄ while the nickel complex has stoichiometry NiLCl₂. The suggested structure for the cobalt and copper complexes is tetrahedral, while for the nickel complex it is octahedral. Thermal analysis studies show that the cobalt and copper complexes form intermediate complexes before their metal oxides are produced. The nickel complex also forms an intermediate complex and then nickel chloride before the nickel oxide is obtained.     

Iron,cobalt and nickel complexes of pyridines

Summary Syntheses, chemical reactivity, physicochemical properties and applications of iron, cobalt and nickel complexes of pyridines are presented.     

Thermal decomposition studies on manganese(III) selenito complexes

The heats of immersion of the systems B₂O₃P₂O₅ and Na₂OB₂O₃P₂O₅ in pyridine have been measured by the use of a solution microcalorimeter. In the composition range R R = atomic ratio, B/P) the heat of immersion was relatively small and was almost independent of R. The heat increased markedly with boron content in R > 1. The increase of heat qualitatively parallels that of surface acidity. Introduction of the Na₂O component reduced both heat of immersion and acidity. MgO was immersed in a benzene solution of benzoic acid. The heat of immersion increased with an increase of surface basicity.     

Far-infrared spectra of lanthanide complexes with 8-hydroxyquinoline

Summary Vibrational spectra of lanthanide oxines have been measured in the far-infrared region. In addition, the similar yttrium complex was investigated for further experimental evidence for the proposed band assignments. The most important metal-oxygen and metal-nitrogen bond vibrations have been attributed to absorptions between 390–350 cm^–1 and 210–170 cm^–1, respectively.

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Ferne IR-Spektren von Lanthanidenkomplexen mit 8-Hydroxychinolin

Zusammenfassung Es wurden die Vibrationsspektren von Lanthanid-Oxinen im fernen IR-Bereich gemessen. Zusätzlich wurde der analoge Yttrium-Komplex untersucht, um die Bandenzuordnungen experimentell zu stützen. Die wichtigsten Metall-Sauerstoff- und Metall-Stickstoff-Bindungsschwingungen wurden den Absorptionen zwischen 390–350 cm^–1 und 210–170 cm^–1 zugeordnet.

     

Thermal decomposition of aluminium hydroxides

The thermal decompositions of the crystalline aluminium hydroxides hydrargillite, bayerite and nordstrandite were investigated by thermogravimetry, differential thermal analysis, X-ray diffraction and infrared spectrophotometry. It was found that these aluminium hydroxides undergo thermal decomposition in the following sequences: hydrargillite-1

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Zusammenfassung Die thermische Zersetzung von kristallinen Aluminiumhydroxiden, wie Hydrargillit, Bayerit und Nordstrandit, wurde thermogravimetrisch, differentialthermoanalytisch, röntgendiffraktometrisch und IR-spektrophotometrisch untersucht. Es wurde festgestellt, da\ diese Aluminiumhydroxide in der folgenden Reihenfolge zersetzt werden: Hydrargillit-I

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Thermal decomposition of nickel(II) complexes under quasi-equilibrium conditions

The stoichiometry of thermal decomposition and the relationship between the thermal parameters (quasi-equilibrium decomposition temperaturesT _D and decomposition entalpies H _D) of NiL₄(NCS)₂ complexes (L=imidazole derivatives) were studied. It was found that changes in the experimental conditions strongly influence the decomposition stoichiometry. TheT _D and H _D can be ordered in the following sequence (according toL): imidazole<2-Me imidazole<2-Et imidazole相似文献