Spectrochemical Properties of Noncubical Transition Metal Complexes in Solutions. XV. Solution Properties of bis(Salicylideneaniline)Copper(II)

The complex obtained by condensation of salicylideneaniline with copper(II) acetate was studied in a variety of solvents. This deep-brown crystalline compound is soluble in common solvents, such as, chloroform, toluene, dioxane, methanol, ethanol, dimethyl formamide, dimethyl sulfoxide, and acetonitrile—a necessary condition for observing solvatochromism. The complex has been characterized by elemental analysis, molar conductivity, EPR, and ultraviolet (UV) and visible (VIS) spectroscopy. The available X-ray data shows planar coordination geometry for the copper center. Combined multi-technique experiments have been applied to confirm the structure of the complex in solution. The molar conductivities indicate nonelectrolytic properties. EPR measurements preclude the possibility of solvent coordination at the axial positions of the complex. Spectroscopic measurements were used to study the coordination properties of donor atoms and their bonding ability, as well as trichromaticity coordinate calculations. The results obtained show that the interactions of metal with donors depend on donor strength and polarity of solvent.     

Spectrochemical Properties of Noncubical Transition Metal Complexes in Solution. XII. Angular Overlap Studies of Salicylideneethylenediamine Cu(II) Complex in Various Solvents

As a part of our general interest in the UV-Vis spectroscopy of multidentate mixed-donor ligands, the (salicylideneethylenediamine)Cu(II) complex has been prepared and characterized by elemental analyses, solubility in common solvents, molar conductivities, and ultraviolet (UV), and visible (Vis) spectroscopy. The combined results of spectrophotometric measurements and EPR spectra, as well as known the X-ray structure for solids, were used to determine the structure of the investigated complex in solutions. The spectra of [Cu(salen)] (H₂salen = salicylideneethylenediamine), were measured in various solvents at room temperature, resolved by Gaussian analysis, and angular overlap model (AOM) treated in C _2v symmetry. Because of overparametrization problems, the bis(salicylaldehyde)Cu(II) complex has been characterized and AOM treated. The results of this have been used for AOM studies of [Cu(salen)]. The effect of the solvents upon the - and -bonding ligand abilities is discussed.     

Spectrochemical properties and solvatochromism of bis(salicylidene-2-amino-3-methylpyridine)copper(II)

The title complex, denoted as [Cu(Msap)₂], is a deep brown solid soluble in common solvents like chloroform, toluene, benzene, dioxane, acetone, methanol, ethanol, 2-propanol, dimethylformamide, dimethyl sulfoxide, and acetonitrile that is a necessary condition for solvatochromism observation. The complex has been characterized by elemental analysis, molar conductivity, ultraviolet, and visible spectroscopy. The available X-ray data for similar compounds show that copper atom adopts planar coordination geometry. The molar conductivities indicate their non-electrolytic properties. The electronic spectra have been used to study the coordination properties of donor atoms and their bonding abilities, as well as solvatochromism. The results obtained show that the interactions of metal with donors depend on solvent polarity and the color changes are subtle.     

Spectrochemical Properties of Noncubical Transition Metal Complexes in Solutions. XIV. Angular Overlap Studies of bis(Salicylidene-2-aminothiazole)Copper(II) in Various Solvents

The copper(II) complex [Cu(sat)], where Hsat is salicylidene-2-aminothiazole (bidentate Schiff - base), was studied in variety of solvents. In the solid state, the complex is black. It has been characterized by elemental analysis, solubility in common solvents, molar conductivity, and ultraviolet (UV) and visible (Vis) spectroscopy. The complex is easily soluble in common solvents such as chloroform, dimethylformamide, dimethyl sulfoxide, and 1,4-dioxane. The known crystal structure of similar compounds shows planar coordination geometry for the copper center. Combined multitechnique experiments have been applied to confirm the structure of the complex in solutions. The molar conductivities indicate their nonelectrolyte properties in all these solvents. The spectroscopic measurements were used to study the coordination properties of donoratoms and their bonding abilities.     

Interactions of ligands with lithium picrate in dioxane

The interaction of several cyclic ethers, poly(ethylene glycol dimethyl ether)s, nitriles, esters and ketones with lithium picrate in dioxane at 25°C was investigated by means of a competition method using cross-linked poly(ethylene oxide) (PEO) as the insoluble ligand. The Langmuir-Klotz isotherm of LiPi binding to the PEO gel gave an apparent binding constant, K, as a function of the concentration of added ligand. Plots of 1/K vs. the ligand concentration then yielded the formation constant, K _L , of the ligand complex with LiPi. The results demonstrate that in dioxane one ligand molecule binds to LiPi. While there is some dependence on the Gutmann donicity number of the respective ligands, steric factors often play a dominant role in determining the value of K _L . The results were compared with complexation data obtained on similar systems but by different methods.     

The structure of the nickel—8-quinolinol complex in some organic solvents

The ultraviolet and visible absorption spectra of the nickel—8-quinolinol complex in chloroform are significantly affected by traces of water. Absorption spectra of the complex in mixed solvents, e.g. dioxane—water, dioxane—methanol and chloroform-methanol, and in chloroform solution containing water, pyridine, or 8-quinolinol are compared. An addition compound is formed in which the mole ratio of the nickel-8-quinolinol complex to the solvent or the base is 1:1 or 1:2. Polymerization occurs by mutual interaction between the nickel-8-quinolinol complexes. A degree of polymerization of 2.2 was obtained; this indicates that the binuclear compound predominates. The structure of the nickel—8-quinolinol complex in organic solvents is discussed.     

Structure of the cobalt complexes with the Schiff base of salicylaldehyde and lysine according to the H NMR spectroscopic data

The Co(II) complex with the Schiff base of salicylaldehyde and lysine is studied by the ¹H NMR method in dioxane and dimethyl sulfoxide (DMSO) solutions. In a dioxane solution, the complex is paramagnetic and dimeric. In the dimer, the cobalt ion coordinates two ligand molecules and each ligand is bound to two cobalt ions. In a water-containing DMSO solution, the complex is diamagnetic due to the oxidation of Co²⁺ to Co³⁺.     

Benzo[1,2-d:3,4-d′] diimidazole derivatives

Bromination of 3,6-dimethylbenzo[1,2-d:3,4-d]diimidazole (Ia) in chloroform with bromine and dioxane dibromide in dioxane leads, through the intermediate formation of perbromides, to the 4-bromo-substituted derivative; 4,5-dibromo-3,6-dimethylbenzo[1,2-d:3,4-d]dimidazole is formed in addition to a monobromo-substituted derivative by the action of potassium bromate in hydrobromic acid on Ia. Nitration of Ia and its 2,7-dimethyl-substituted derivative (Ib), even under severe conditions, leads to the 4-mononitro derivatives. Only one of the pyridine nitrogen atoms is quaternized by the action of excess methyl iodide on Ia, b.See [1] for communication II.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 107–110, January, 1973.     

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.

     

Solvent extraction study of cobalt(II) with 8-mercaptoquinoline

Equilibrium distribution coefficients have been determined for the extraction of cobalt(II) with 8-mercaptoquinoline as a function of pH and reagent concentraton at ambient temperature. The extractable complex is a diadduct, i. e. two molecules of the reagent are coordinated to the cobalt(II) chelate. The adduct formation constant in chloroform and the overall formation constant in the aqueous phase have been determined. Pyridine and its methyl derivatives were found to enhance the extraction of Co(II) into chloroform in the presence of 8-mercaptoquinoline. From the extraction equilibrium data, the adduct formation constants of 12 chelate to nitrogen base adducts were evaluated. The special role of steric factors is discussed.     

Phase separation of poly(γ-benzyl L-glutamate) to liquid crystal and isotropic solution in various helicogenic solvents

Solvent effects on the phase separation of poly(-benzyl L-glutamate) to liquid crystal and isotropic solution have been observed in various helicogenic solvents. The temperature-composition phase diagrams have been determined for each solution. The critical concentrations, ₂ ^* , at which the phase separation occours have been compared in various solvents. In dimethylformamide in which the polymer is molecularly dispersed, the observed ₂ ^* value has agreed with that calculated by Flory's theory. In some solvents in which the polymer aggregates in a head-to-tail mode such as chloroform, the observed ₂ ^* values have been considerably small. It is assumed that the polymer aggregates behave as longer particles than the original particles. In dioxane in which the polymer aggregates highly both in a head-to-tail and a side-by-side modes, the ₂ ^* value has been a little larger than that in chloroform. In this case the relationship between the aggregation and the liquid crystal formation is so complicated that further investigation is necessary. In aromatic solvents such asm-cresol that dissolves the polymer almost molecularly, the ₂ ^* is smaller than that in dimethylformamide. Therefore, the intermolecular interactions between the phenyl groups in the side groups of the polymer and those in solvent molecules must be considered.The author is grateful to Mr. K. Sano and Mr. M. Watanabe for their observation of the liquid crystal formation.     

H-bond acidity of solvents: II. Transformation of the Snyder chi proton donor scale to the Taft-Kamlet alpha scale

By including a solvent cohesion term it was possible to transform Snyder's χ_d scale into the Taft-Kamlet α scale for aliphatic H-bonding solvents. The transforming equation was: $$\alpha = 2.386_{\chi d} + 1.27\alpha \beta - 0.482$$ where αβ is the product of solvent acidity and basicity. Alpha is estimated for several solvents previously not thought to posses H-donor ability. These are dimethyl sulfoxide, nitroethane, dimethylformamide, dioxane, dimethylacetamide, propylene carbonate, ethyl acetate, butyrolactone, N-methylpyrrolidinone, and cyclohexanone.     

Studies on the liquid-liquid extraction and ion and precipitate flotation of Co(II) with decanoic acid

The liquid-liquid extraction, ion and precipitate flotation of Co(II) from chloride media of 1·10^–4M initial Co(II) concentration and =0.1 have been investigated using decanoic acid and the results are compared. Organic solvents used were chloroform in the case of liquid-liquid extraction and ethanol (used as a solvent for the collector and a frother) in the case of flotation. From the results it appears that liquid-liquid extraction takes place through the formation of the complex: (CoR₂)₂(HR)₂ but flotation occurs through the formation of a surface active product which has the empirical formula CoR₂. The effects of pH and of decanoic acid concentration on the three separation processes were also investigated and the results discussed. Good agreement was observed between the experimental precipitate flotation curves and the theoretical curve calculated from the data published for Co(II) hydrolysis.     

Synthesis and structure of <Emphasis Type="Italic">cis</Emphasis>-dichloro(triphenylstibine)(dimethylsulfoxide)platinum(II)

The platinum molecular complex cis-Cl₂(Ph₃Sb)(Me₂S=O)Pt (I) was synthesized by the reaction of tetraphenylstibonium chloride with potassium tetrachloroplatinate in dimethyl sulfoxide. The crystal structure of square-planar complex I was determined by X-ray crystallography. The complex contains, in addition to chlorine atoms, triphenylstibine and DMSO molecules coordinated to the central atom. The bond lengths Pt-Cl, Pt-S, and Pt-Sb are 2.308(1), 2.350(1), 2.195(1), and 2.5118(4) Å, respectively. The compound is the first example of mixed-ligand platinum(II) complex in which the coordination sphere of the central atom contains, along with dimethyl sulfoxide ligand, a tertiary stibine ligand.     

Interactions between Crown Ethers and Water,Methanol, Acetone,and Acetonitrile in Halogenated Solvents

The interactions between crown ethers and water, methanol, acetone, and acetonitrile molecules in halogenated solvents are studied by means of calorimetric measurements. The results reveal the formation of 1:1 complexes between crown ethers and water in chloroform. The hydrogen bonding and ion–dipole interactions are responsible for the complex formation between the water molecules and crown ethers. For a better understanding of the influence of chloroform upon the complexation between crown ethers and water, chloroform is replaced by dichloromethane, 1,2-dichloroethane, and carbon tetrachloride. Since the hydrogen bonds are responsible for the complex formation between crown ethers and water in the halogenated solvents, further investigations are performed with methanol, acetone and acetonitrile. The interactions, the ligand nature, the concentrations of polar solvents, and the nature of nonpolar solvents involved in complexation are analyzed and discussed.     

Spectrophotometric study of the reaction of Co(II) and Ni(II) with nitroso-R-salt and α-nitroso-β-naphthol

The complexes of Co(II) and Ni(II) with nitroso-R-salt are studied by conductometric titration and spectrophotometric methods in buffer solutions of differentpH. The study proved the possible formation of (11), (12) and (13) complexes for Co(II) while Ni(II) forms (11) and (12) complexes (metal:ligand) only. The factors affecting complex formation are established and the formation constants of the complexes are evaluated. The ir spectra of the solid complexes with -nitroso--naphthol revealed that the ligand exhibits the nitrosophenol structure and that the reaction takes place through proton displacement from the OH-group.

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Spektrophotometrische Studie zur Reaktion von Co(II) und Ni(II) mit Nitroso-R-Salz und -Nitroso--naphthol

Zusammenfassung Es wurden die Komplexe von Co(II) und Ni(II) mit Nitroso-R-Salz mittels konduktometrischer und spektrophotometrischer Methoden in Puffer-Lösungen mit verschiedenempH untersucht. Für Co(II) wurden (11)-, (12)- und (13)-Komplexe gefunden, während für Ni(II) lediglich (11)- und (12)-Komplexe (Metall:Ligand) festgestellt werden konnten. Die Faktoren, die die Komplexierung bestimmen, werden diskutiert und die Komplexbildungskonstanten wurden bestimmt. Die IR-Spektren der Komplexe mit -Nitroso--naphthol zeigen, daß der Ligand in der Nitrosophenol-Form vorliegt und daß die Reaktion über eine Protonenverschiebung von der OH-Gruppe verläuft.

     

Synthesis and electrochemical properties of a series of novel tetra(4-benzoyl)phenoxyphthalocyanine derivatives

A novel phthalocyanine,2,9(10),16(17),23(24)-tetra(4-benzoyl)phenoxyphthalocyanine,and its complexes with Zn(II),Cu(II),Co(II),and Ni(II) have been synthesized and characterized by a combination of elemental analysis,IR,1 H NMR,UV-vis spectroscopy and mass spectrometry.All of the materials are very soluble in common organic solvents such as dichloromethane,chloroform,tetrahydrofuran,N,N-dimethylformamide and dimethyl sulfoxide.The Q band wavelengths of the complexes decrease in the order:Zn > Cu > Ni > Co.Redox processes were observed at 1.06,0.74,0.51 and 0.98 V for the free phthalocyanine,at 0.72 and 1.04 V for the Co(II) complex,at 1.24,0.77,0.24,0.61 and 0.91 V for the Cu(II) complex,and at 0.74 and 1.20 V for the Ni(II) complex.The cyclic voltammograms of the phthalocyanine ring of the four species are similar,with reduction and oxidation couples each involving a one-electron transfer process.     

Solvent extraction of Ni/II/ with isonitrosobenzoylacetone into chloroform

A method has been developed for the quantitative extraction of Ni/II/ with isonitrosobenzoylacetone /HINBA/ into chloroform. The effect of various parameters on the extraction coefficient value such as pH, time of equilibration, effect of solvents, anions, cations etc. have been studied. The stoichiometry of the metal: reagent determined by the method of substoichiometric extraction and slope ratio method was found to be 12. Decontamination factors for many elements in the substoichiometric extraction of Ni/II/ were also evaluated.     

Electrochemical behaviour of a series ofN,N′-1,2-Phenylenebis(salicylideneimin)ato transition metal complexes

Summary The electrochemistry of a series of nickel(II), copper(II), cobalt(II), manganese(II) and oxovanadium(IV) complexes with theN,N-1,2-phenylenebis(salicylideneimin)ate ligand has been studied in dimethyl sulfoxide solution. Kinetic and thermodynamic aspects of the electron-transfer processes are discussed, also with respect to those of the correspondingN,N-ethylenebis(salicylideneimin)ate and bis(salicylideneiminate-3-propyl)amine derivatives     

Calorimetric determination of the enthalpy of specific interaction of chloroform with a number of proton-acceptor compounds

Calorimetry was used to measure the enthalpies of solution of chloroform in various proton-acceptor solvents and, vice versa, proton-acceptors in chloroform. Based on a previously proposed equation, the enthalpies of specific interaction were calculated and compared with the published data on the enthalpy of hydrogen bonding of chloroform with various proton-acceptor solvents. The composition of the H-bonded complexes mainly formed during the dissolution of proton-acceptor solutes in chloroform was established. It was demonstrated that the dissolution of ethers in chloroform is predominantly accompanied by the formation of 1: 1 complexes, while the dissolution of acetone, dimethylformamide, and dimethyl sulfoxide in chloroform gives rise to more complex associates.