Transition metal complexes with hydrazides and hydrazones

A study was made of the thermal decomposition of octahedral Co(II) complexes of the type CoL_n X ₂·mH₂O, wheren=2 and 3,m=1,2 and 5 andX=Cl, Br, I, NCS, OAc andv ₂So₄, in both air and nitrogen atmospheres. It was established that the complexes are completely decomposed below 800° and CoO is formed as final product. The most probable decomposition mechanism was proposed. The tris(ligand) complexes were characterized by elemental analysis, and spectral and magnetic measurements, and all the data suggested the presence of a point group symmetry of type O_h.

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Zusammenfassung Sowohl in Luft als auch in Stickstoffatmosphäre wurde die thermische Zersetzung von oktaedrischen Co(II)-Komplexen der allgemeinen Formel CoL_nX₂· mH₂O (n=2 und 3,m=1, 2 und 5,X=Cl, Br, I, NCS, OAc und SO₄) untersucht. Es wurde festgestellt, daß sich die Komplexe unterhalb 800°C vollkommen zu CoO als Endprodukt zersetzen. Der wahrscheinlichste Zersetzungsmechanismus wurde unterbreitet. Die tris-Ligandenkomplexe wurden mittels Elementaranalyse sowie Spektral- und magnetischen Untersuchungen charakterisiert, alle Angaben deuten auf eine Punktsymmetriegruppe vom Typ Oh hin.

     

Spectrophotometric studies of the complexes of group IIIa metal ions with some phenylazo-8-quinolinol dyes

A new rapid precise method for the spectrophotometric microdetermination of group IIIA metal ions with 5-phenylazo-8-quinolinol (I) and 5-(p-chlorophenylazo)-8-quinolinol (II) is given. The optimum conditions favouring the formation of the complexes are reported, as are the compositions of the complexes, their stabilities, and the ranges for obedience to Beer's law. Spectrophotometric titration methods for Al, Ga and In with EDTA in presence of ligand I or II as indicator are also described.     

Spectrophotometric and solvent extraction study of o-hydroxybenzaldehyde isonicotinoyl hydrazone complexes with gallium and indium

Complex formation of o-hydroxybenzaldehyde isonicotinoyl hydrazone with Ga^III, In^III and Tl^III has been studied. The thallium complex is unstable. The composition and the instability constants of gallium and indium complexes were determined. Molar absorptivity of gallium complex at 390 nm is 3.40 × 10⁴ and that of indium at 380 nm is 3.20 × 10⁴ l mole^?1 cm^?1. Both complexes were found to be rapidly and quantitatively transfered into 1-pentanol. The corresponding aluminum complex is not extracted. Possible analytical application for separation and spectrophotometric determination of these elements is also examined.     

Syntheses and studies on some metal beta-thioketoester complexes

The syntheses of four metal complexes from ethyl thiobenzoylacetate are described. These complexes are of the type M[C₆H₅C(S)CHC(O)OC₂H₅]_n where M is nickel, palladium, zinc or cobalt and n is 2 or 3. The IR spectra of these complexes show the presence of a chelating conjugated ester carbonyl group. The ¹³C NMR spectra and dipole moment data of these complexes are also presented and a comparison of the dipole moments of these metal complexes of C₆H₅CSCH₂COR′ where R′ is OC₂H₅ or CF₃ is made. The ¹³C NMR spectrum of the octahedral cobalt complex suggest a facial configuration.     

Spectrophotometric studies,stability constants and thermodynamics for complexes ofo-hydroxyacetophenone isobutyroylhydrazone with some bivalent transition metal ions

Summary The u.v. spectra ofo-hydroxyacetophenone isobutyroylhydrazone (HAIBuH) were investigated in pure organic solvents as well as in Britton Robinson buffer solutions of varyingpH values. The interaction ofHAIBuH with Co(II), Ni(II) and Cu(II) were studied spectrophotometrically. The optimumpH favouring the formation of the highly coloured complexes are 8.5, 8.0 and 7.5 for Co(II), Ni(II) and Cu(II), respectively. The stoichiometries of these complexes were determined and indicated the formation of 1:2 (metal:ligand) complexes of Co(II) and Ni(II) and a 1:1 complex of Cu(II). The dissociation constantspK ^H ofHAIBuH and the overall stability constants log of their complexes were determined at different temperatures (293, 303 and 313 K). The corresponding thermodynamic parameters (G, H and S) in 20% (v/v) ethanol-water mixture were derived and discussed.

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Spektrophotometrische Untersuchungen, Stabilitätskonstanten und Thermodynamik der Komplexe vono-Hydroxyacetophenonisobutyroylhydrazon mit einigen bivalenten Übergangsmetallionen

Zusammenfassung Die UV-Spektren vono-Hydroxyacetophenon-isobutyroylhydrazon (HAIBuH) wurden in reinen organischen Solventien und in Britton-Robinson-Pufferlösungen von verschiedenempH gemessen. Die Wechselwirkung vonHAIBuH mit Co(II), Ni(II) und Cu(II) wurde spektrophotometrisch untersucht. Die optimalenpH-Werte zur maximalen Ausbildung der starkgefärbten Komplexe sind 8.5, 8.0 bzw. 7.5 für Co(II), Ni(II) bzw. Cu(II). Für die Stöchiometrien wurde ein Metall: Ligand-Verhältnis 1:2 für Co(II) und Ni(II) und 1:1 für Cu(II) bestimmt. Die DissoziationskonstantenpK ^H vonHAIBuH und die Gesamtstabilitätskonstanten log der Komplexe wurden bei verschiedenen Temperature bestimmt (293, 303 und 313 K) und die entsprechenden thermodynamischen Parameter (G, H und S) in 20% (v/v) Ethanol-Wasser-Mischung errechnet und diskutiert.

     

Preparation and characterization of some transition metal complexes of benzoic acid hydrazones of 2-aminonicotinaldehyde

Summary Cu^II, Ni^II, Co^II, Zn^II and Pd^II complexes of tridentate Schiff base ligands derived from the condensation of benzoic acid hydrazides with 2-aminonicotinaldehyde have been prepared and characterized. For M=Cu, Ni, Co and Zn the complexes were formulated as [M(ligand)(H₂O)X] (X=Cl, Br), with a distorted octahedral geometry and tridentate Schiff base ligands. The Pd complexes were formulated as Pd(ligand)Cl₂, with square planar geometries and bidentate Schiff base ligands. The e.s.r. spectra of the Cu^II complexes are discussed.     

A theoretical study of the solvent extraction of multipolymeric metal complexes

A mathematical treatment is demonstrated which explores the simultaneous extraction of multipolymeric complexes. The theory will predict that there may be only a finite number of species which can exist.     

Spectrophotometric solvent extraction studies of 2-mercaptopyridine-1-oxide and uranyl ion complex

The complex formed by uranyl ion with 2-mercaptopyridine-1-oxide (thione) is studied by spectrophotometry. At pH 4.5 and 25 degrees the only complex formed is UO(2)(thione)(3)(-). The conditional stability constant of this complex is 2.6 x 10(12). Tributyl phosphate is used for the extraction of the complex from the aqueous phase and the extraction constant is 8.9 x 10(12). The use of the reagent for the separation and determination of uranyl ion is elaborated.     

Molecular orbital studies of some transition metal complexes

A set of molecular orbital calculations based on a particular semi-empirical method, has been undertaken on a homologue series of bis(-2-methylallyl)transition metal (Ni, Co, Fe, Cr) complexes (abbreviated as ML₂). Arguments are found for predicting the stability of the NiL₂ system, which is the only one that could be synthetized.

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Zusammenfassung Eine Reihe von semiempirischen MO-Rechnungen wurde für die homologe Reihe von bis(-2-methylallyl) Metallkomplexen (Ni, Co, Fe, Cr) durchgeführt. Gründe für die Stabilität der Ni-Verbindung, die als einzige synthetisiert wurde, werden angeführt.

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Résumé Un ensemble de calculs par une méthode semi-empirique particulière d'orbitales moléculaires a été effectué sur une série homologue de complexes bis (-2-méthylallyl)-métal de transition (Ni, Co, Fe, Cr): ML₂.Certains arguments sont trouvés en faveur de la stabilité du système NiL₂, le seul à avoir été synthétisé.

     

二茂铁基取代酰腙的一些过渡金属配合物

本文制备了两个金属有机配位体,肉桂醛二茂铁基甲酰腙(HL^1)和二[(1-肉桂酰肼基乙基)环戊二烯基]铁(H~2L^2)及它们与一些过渡金属的配合物:ML~2^1[M=Cu(II)],ML^2[(M=Cu(II)和Zn(II)],M(HL^1)~2Cl~2[M=Cd(II),Co(II)和Ni(II)],M(H~2L^2)Cl~2[M=Mn(II),Zn(II),Co(II)和Cd(II)]。这两个配位体以烯醇式与M(OAc)~2.nH~2O中心离子配位,与MCl~2.nH~2O则以酮式配位。     

Thermal degradation studies on some metal hydrazinic complexes

The paper deals with the characterization of three hydrazinic complexes with Ni, Cu and Cr respectively, by means of non-isothermal thermal methods, TG, DTG and DTA, under nitrogen atmosphere in order to investigate the structure-thermostability-thermal degradation mechanism correlation. The thermal analysis made evident the degradation mechanisms characteristic of every sample in accordance with the chemical structure. The quantitative analysis by TG-DTG afforded the estimation of the metal amount in the complex on the basis of the resulting metallic oxide nature as well as of some aspects of the thermal degradation mechanism supported by mass spectral measurements. The melting points given by DTA and confirmed by the Boetius method and the initial temperatures of thermal degradation from TG-DTG-DTA afforded to ascertain the temperature range proper for using and storing the complexes under study which show potential practical applications as drugs.     

Thermal studies of some purine compounds and their metal complexes

The mechanism of the decomposition of the entitled compounds and their complexes is studied. Adenine, its Schiff base of salicylaldehyde, and its azo resorcinol derivatives are ended with carbon. However, oxalonitrile compound is appeared as a final product for adenine acetylacetone and an intermediate for adenine. The thermodynamic parameters of the decomposition reaction were evaluated and discussed. The change of entropy values, ΔS ^#, showed that the transition states are more ordered than the reacting complexes. The thermal processes proceed in complicated mechanisms where the bond between the central metal ion and the ligands dissociates after losing small molecules such as H₂O, NH₃, or HCl. In most cases, the free radical species of the ligands are assigned to exist through decomposition mechanisms. The copper adenine and nickel salicylaldehyde complexes are ended with the metal as a final product. However, the cobalt adenine, its acetylacetone, its salicylaldehyde, cadmium and mercury guanine complexes are ended with metal oxides.     

Synthesis and further reactivity studies of some transition metal gallyl complexes

Reactions of the anionic gallium(I) heterocycle salt, [K(tmeda)][Ga(DAB)] (DAB = {N(Dip)C(H)}₂; Dip = C₆H₃Prⁱ₂-2,6), with a series of groups 6-9 and 11 metal halide complexes have given rise to the metal gallyl complexes, [CpCr(IMes){Ga(DAB)}] (IMes = :C{(Mes)NC(H)}₂; Mes = mesityl), [M(tmeda){Ga(DAB)}₂] (M = Mn, Fe or Co) and [Cu(dppe){Ga(DAB)}] (dppe = 1,2-bis(diphenylphosphino)ethane). The majority of the complexes have been crystallographically characterized. The reactivity of the previously reported copper(I) gallyl complex, [(IPr)Cu{Ga(DAB)}] (IPr = :C{(Dip)NC(H)}₂), towards a variety of unsaturated substrates has been explored. Three crystallographically characterized complexes have arisen from this phase of the study, viz. [(IPr)CuCCPh], [(IPr)Cu{Ga(DAB)}(CNBu^t)] and [(IPr)Cu{κ¹-OC(O)C(CNHDip)(NHDip)}]. The results of these investigations show that the reactivity of [(IPr)Cu{Ga(DAB)}] is significantly different to that of related copper boryl complexes.     

studies in the solvent extraction of some thallium(I) chelates

Studies of the extraction of thallium(I) from aqueous solution into chloroform or MIBK using 6 reagents have been made. Reagent concentration, pH variation, and the addition of adductforming agents to the organic phase have all been investigated. Association constants and distribution coefficients for several of the better reagents have been determined. Theoretical interpretations have permitted the identification, of participating species and the calculation of equilibrium constants in several cases.     

Electrical conductivity of some hydrazones and binary complexes with transition metals

Summary The electrical behaviour of some hydrazones was studied in the temperature range of 290–435 K. The effect of complex formation with Mn(II), Fe(II), Co(II), Ni(II), and Cu(II) on the electrical conductivity of the hydrazones was investigated. The structure of the hydrazones was characterized using¹H and¹³C NMR spectroscopy. Conductometric titration and IR spectroscopy were used to illustrate the structure of the hydrazone complexes. Both the structures of the hydrazones and the complexation process play an effective role in the conduction process.

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Elektrische Leitfähigkeit einiger Hydrazone und ihrer binären Komplexe mit Übergangsmetallen

Zusammenfassung Das elektrische Verhalten einiger Hydrazone und ihrer Komplexe mit Mn(II), Fe(II), Co(II), Ni(II) und Cu(II) wurde im Temperaturbereich von 290 bis 435K untersucht. Die Strukturen der Hydrazone wurden mittels¹H- und¹³C-NMR-Spektroskopie charakterisiert, jene ihrer Komplexe durch konduktometrische Titration und IR-Spektroskopie. Sowohl die Strukturen der Hydrazone als auch der Komplexbildungsvorgang spielen eine wesentliche Rolle beim Leitungsvorgang.

     

Stability of transition metal complexes involving three isomeric quinolyl hydrazones

The stability constants of three isomeric quinolyl hydrazones; {4,6-(para); 4,7-(meta) and 4,8-MeBHQ(ortho)} towards some bivalent metal ions have been determined in 75% solvent (dioxane, isopropanol, ethanol and methanol)-water by a pH-titrimetry. The insertion of the Me-group in the 8-position decreases the stability of the complexes to a great extent. The complexation of the ortho-derivative is endothermic, whereas that of the para-derivative is exothermic. Using the solvent parameters, the stability constants of the para-derivative towards Co(II), Ni(II) and Cu(II) ions were evaluated in aqueous medium by five different methods. Also, the electronic absorption spectra of the ortho-hydrazone have been studied in solvents of various polarities to investigate the dependence of the band shift (Δ?) on the solvent parameters viz. 1/D, Z, E(T), DN, AN and (α, β, π*). The interaction of the hydrazones with CoCl(2)·6H(2)O afforded an octahedral complex in case of the ortho-hydrazone and square planar complexes in case of the meta- and para-hydrazones.     

Spectrophotometric investigation of analytically important metal complexes

Summary A convenient way of estimation of composition, molar absorptivity, effective and overall stability constants of complexes M _m Y _i H _j L _n is described.

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Spektrophotometrische Untersuchung von analytisch bedeutenden Metallkomplexen

Zusammenfassung Methoden zur Berechnung der Zusammensetzung, des molaren Extinktionskoeffizienten sowie der effektiven und Brutto-Stabilitätskonstanten von Komplexen der Art M _m Y _i H _j L _n werden beschrieben.

     

Preparation, characterization and thermal studies of some transition metal ternary complexes

Ternary complexes of Co(II), Ni(II), Cu(II) and Zn(II) with nitrilotriacetic acid as a primary ligand and glycine as secondary ligand were prepared in slightly acid medium. Their molecular masses were determined by acid-base titration against standard potassium hydroxide solution. Their molecular structures were found to be [M (HNTA)(glyH)(2H₂O)]. Thermogravimetric analysis confirmed this structure and that the water present is coordinated to the central metal atom. UV-Vis spectra showed that the complexes have octahedral symmetry. IR spectra suggested the presence of intermolecular hydrogen bonding. This phenomenon was supported by mass spectra. The ionization constants of these complexes, as diprotic acids, were determined.