Stereochemical versatility of Cu(II): Cu(II) complexes of benzyl methyl ketone semicarbazone

Copper(II) complexes of the general composition Cu(ligand)₂X₂ (where X = Cl, Br, NO₃, ClO₄, and $\text{1}\text{2}$SO₄) and Cu(ligand)(CH₃COO)₂ have been synthesised with benzymethylketonesemicarbazone. All the complexes prepared have been characterised by elemental analysis, magnetic moment, conductance, IR, electronic and electron spin resonance spectral studies. The complexes Cu(ligand)₂X₂ (X = Cl, Br, NO₃) and Cu(ligand)(CH₃COO)₂ may have tetragonal symmetry while the Cu(ligand)₂X₂ (ClO₄ and $\text{1}\text{2}$SO₄) may be five-coordinate trigonal bipyramidal in structure.     

Solvent extraction of lead(II) with N-cyclohexyl-N-nitrosohydroxylamine into methyl isobutyl ketone

The distribution equilibrium of the lead-cnha complex in the water-methyl isobutyl ketone (MIBK) system has been studied at 25 degrees . From graphical treatment of the equilibrium data, it was deduced that PbL(2) is the complex extracted. By use of the program LETAGROP-DISTR, values for the distribution and the stability constants of PbL(2) have been calculated: log K(DC) = 1.84 +/- 0.11; log beta(1) = 6.68 +/- 0.09 and log beta(2) = 10.28 +/- 0.09. On the basis of these results and those of previous studies, a method for determination of lead(II), copper(II) and cadmium(II) by atomic-absorption spectrometry, after extraction with cnha and 4-methylpyridine into MIBK, is proposed.     

Solvent extraction of Cd(II) with N-cyclohexyl-N-nitrosohydroxylamine and 4-methylpyridine into methyl isobutyl ketone

The distribution equilibria of the complexes cadmium-cnha and cadmium-cnha-4-methylpyridine in the water-methyl isobutyl ketone system have been studied at 25 degrees , by using (109)Cd as a radiotracer to measure the metal distribution ratio. A very sensitive method for detection of (109)Cd, based on the use of a liquid scintillator, has been developed. From the graphical treatment of the equilibrium data, it has been deduced that CdL(2) is the complex extracted in the absence of 4-methylpyridine, and that the adduct CdL(2)B is extracted when the second ligand is present. This model has been checked by treating the data with the program LETAGROP-DISTR and the following equilibrium constants have been obtained: stability constants of CdL(2), log beta(1) = 2.82 +/- 0.14, log beta(2) = 5.981 +/- 0.004; distribution constant of CdL(2), log K(DC) = -0.49 +/- 0.01; adduct formation constant of CdL(2)B, log K(s) = 2.70 +/- 0.07.     

Determination of germanium after extraction by methyl isobutyl ketone. II

Summary Germanium extracted by methyl isobutyl ketone from 7.5N hydrochloric acid solutions is made to react directly in the organic phase with phenylfluorone. Very stable colored solutions are obtained. The reaction is instantaneous and twice as sensitive as when carried out in aqueous medium with the same reagent. Optimum range of concentration for absorptiometric measurements was found to be 0.08 to 0.30g Ge/ml. Most of the interfering ions are separated by preliminary extraction of the cupferrates with the same ketone. W(VI) and Nb(V) are removed by previous extraction with excess thiocyanate in reducing medium making use of the same solvent. The procedure is applicable to the determination of germanium in coals.

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Zusammenfassung Germanium wird aus 7,5-n Salzsäure mit Methylisobutylketon extrahiert und unmittelbar in der organischen Phase mit Phenylfluoron umgesetzt. Die Reaktion erfolgt sofort, ist doppelt so empfindlich als in wäßriger Phase und führt zu sehr stabil gefärbten Lösungen. Die für Absorptionsmessungen am besten geeignete Konzentration liegt zwischen 0,08 und 0,30g Ge/ml. Die meisten störenden Ionen werden durch vorhergehende Extraktion ihrer Cupferonate mit demselben Keton entfernt. Wolfram(VI) und Niob(V) werden mit demselben Lösungsmittel in Gegenwart überschüssigen Rhodanids in reduzierendem Milieu abgetrennt. Das Verfahren eignet sich für die Bestimmung von Germanium in Kohle.

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Résumé On fait réagir directement le germanium avec la phénylfluorone, dans la phase organique, après son extraction par la méthylisobutylcétone de sa solution 7,5N chlorhydrique. On obtient ainsi des solutions colorées très stables. La réaction est instantanée et deux fois plus sensible que lorsqu'elle est effectuée en milieu aqueux avec le même réactif. Le domaine de concentration optimum pour les mesures absorptiométriques est situé entre 0,08 et 0,30g Ge/ml. La plupart des ions gênants sont séparés par une extraction préalable des cupferrates par la cétone. W(VI) et Nb(V) sont éliminés au cours d'une extraction préalable en présence d'un excès de thiocyanate en milieu réducteur et dans le même solvant. La technique est applicable à la détermination du germanium dans les charbons.

     

Extraction of vanadium into isobutyl methyl ketone

Because of its advantages in atomic-absorption spectroscopy, isobutyl methyl ketone was chosen as organic solvent for an extraction study on vanadium. Of eight chelating agents which were evaluated for completeness of extraction, ease of use, working pH range, and freedom from interference, cupferron was judged best.     

Equilibrium and kinetics of Zn(II) bromide extraction with Amberlite LA-2 and methyl isobutyl ketone

The rates of extraction of Zn(II) from hydrobromic acid solutions into benzene solutions of the liquid anion exchanger Amberlite LA-2 and those into methyl isobutyl ketone (MIBK) have been investigated. The distribution equilibria of this system have been also studied. Under the used experimental conditions the extracted species of Zn(II) have been proposed. The kinetic data indicated a first order reaction with respect to Zn(II) in both systems, nearly one with respect to HBr and from 0–0.38 for LA-2. In case of extraction of Zn(II) with methyl isobutyl ketone, MIBK, the reaction order with respect to MIBK was found to be 4 and with respect to HBr inverse first order. The rate constants of these extraction processes were determined and the rate determining steps were discussed in the light of the obtained results.     

Solvent extraction of N-Cyclohexyl-N-Nitrosohydroxylamine (cnha) into some organic solvents and of the Cu(II)-cnha complex into methyl isobutyl ketone

The distribution equilibria of N-cyclohexyl-N-nitrosohydroxylamine (cnha) in the water-chloroform, water-hexane, water-methyl isobutyl ketone (MIBK) and water-isopentyl alcohol systems, and of the Cu(II)-cnha complex in the water-MIBK system have been studied. From the distribution data the dissociation and distribution constants of the reagent have been calculated; their values are pK(a) = 5.55 +/- 0.10; log K(DR) = 2.46 +/- 0.05 (chloroform), 1.76 +/- 0.11 (MIBK), 1.06 +/- 0.07 (hexane) and 1.48 +/- 0.06 (isopentyl alcohol). In the same way the values of the distribution and stability constants of the Cu(II) complex have been obtained; log K(DC) = 3.51; log beta(1) = 7.23 +/- 0.10 and log beta(2) = 12.00 +/- 0.08. For the determination of cnha in the aqueous phase saturated with MIBK, a spectrophotometric method based on the coloured complex formed by the reagent with Fe(III) has been established. Finally, an analytical method for Cu(II) by atomic-absorption spectrometry after its extraction with cnha into MIBK, is proposed. Its detection limit is 4.6 mug l ., its precision +/- 2.1% and its accuracy 97.5%. This method has been applied to the determination of the copper content in the surface water of the Congest River of Catalonia (Spain).     

Copper(II) complexes with aroylhydrazones

The coordination chemistry of copper(II) with tridentate aroylhydrazones is briefly discussed in this article. Two types of aroylhydrazones derived from aroylhydrazines and ortho-hydroxy aldehydes or 2-pyridine-carboxaldehyde have been used. The characterization of the complexes has been performed with the help of various physico-chemical techniques. Solid state structural patterns have been established by X-ray crystallography. In the solid state, structural varieties of these complexes are seen to range from monomeric, dimeric, polymeric and one-dimensional self-assembly via hydrogen bonds and π-π interactions. EPR spectroscopy and variable temperature magnetic susceptibility measurements have been used to reveal the nature of the coordination geometry and magnetic characteristics of these complexes.     

Extraction into methyl isobutyl ketone of metal complexes with ammonium pyrrolidine dithiocarbamate formed in strongly acidic media

It is shown that stable metal complexes with ammonium pyrrolidine dithiocarbamate (APDC) are formed in strongly acidic (0.5–6 M) solutions and can be extracted into methyl isobutyl ketone (MIBK), although APDC is normally used for extractions from solutions at pH 2–12. Percentage extraction curves are presented for 24 elements (Ag, As, Au, Bi, Cd, Co, Cu, Fe, Ga, Ge, Hg, In, It, Ni, Os, Pb, Pd, Pt, Rh, Ru, Sb, Sn, Tl and Zn) from solutions of hydrochloric or nitric acid with and without addition of APDC. Some elements (e.g., Fe, Ga, Ge, In and Au) show identical extractions as their chloro complexes in hydrochloric acid with or without APDC. Others (e.g., Ni, Cu, Pd, As, Ag, Sb, It, Hg and Bi) are strongly extracted (K_d ? 20), from 2 M hydrochloric or nitric acid in the presence of APDC. Palladium (K_d = 8000), Sb (K_d = 10 000), and Bi (K_d = 3500) are particularly easily extracted. The potential of the extraction system was tested by extraction and quantification of palladium from the CANMET standard ore PTC-1; the mean value found was 12.55 μg g^?1 (ppm) palladium with a relative standard deviation of 7.6% (n = 12) and a relative error of 1.2% from the recommended value of 12.70 μg g^?1.     

Coulometric generation of hydrogen ions by oxidation of mercury in methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone

Mercury(II)-chloride reacts with anhydrous methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone in a precise stoichiometry ratio (1:2), and weakly ionized compounds of mercury with ketones are formed and equivalent quantity of HCl is released. The application of a mercury anode for the quantitative generation of H⁺ ions in 0.25 M sodium perchlorate in anhydrous methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone has been investigated. Current/potentials curves for the solvents, titrated bases, indicator and mercury showed that in these solvents mercury is oxidized at potentials much more negative than those for the titrated bases and other components present in the solution. The protons generated in this way have been used for the titration of some organic bases, with either visual or potentiometric end-point detection. The oxidation of mercury in methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone and the reaction of mercury ions with these solvents have been found to proceed with 100% current efficiency.     

Copper(II) complexes of pyrrolidine dithiocarbamate

Copper(II)-pyrrolidine dithiocarbamate (PDTC) complexes having the general formula, [Cu(PDTC)₂], [Cu(PDTC)X₂]⁻ (where X = Cl⁻, I⁻, CN⁻, SCN⁻) and [Cu(PDTC)(en)]⁺ (en = ethylenediamine) have been prepared and characterized by IR spectroscopy and by thermogravimetric analysis (TGA and DTA). The IR data suggests that coordination of pyrrolidine dithiocarbamate (PDTC) takes place through the two sulphur atoms in a symmetrical bidentate fashion. The results of thermal analysis are consistent with the proposed composition of the complexes.     

Copper(II) complexes of sulfanilamide derivates

Summary Nine different Cu^II(sulf)₂ and three mixed Cu^II(sulf)₂X_2–3 (X=NH₃ or pyridine) derivatives were prepared from Cu^II and sulfanilamides (sulfH=sulfadiazine, sulfadimethoxine, sulfadimidine, sulfamerazine, sulfamethoxydiazine, sulfamethoxypyridazine, sulfapyridine, sulfathiazole and sulfisomidine) in alkaline solution and their e.s.r., i.r. and ligandfield spectroscopic properties were evaluated. Two types of Cu(sulf)₂ complexes were formed: dimeric and monomeric/ polymeric species.     

Spectroscopic evaluation of Co(II), Ni(II) and Cu(II) complexes derived from thiosemicarbazone and semicarbazone

Co(II), Ni(II) and Cu(II) complexes were synthesized with thiosemicarbazone (L(1)) and semicarbazone (L(2)) derived from 2-acetyl furan. These complexes were characterized by elemental analysis, molar conductance, magnetic moment, mass, IR, electronic and EPR spectral studies. The molar conductance measurement of the complexes in DMSO corresponds to non-electrolytic nature. All the complexes are of high-spin type. On the basis of different spectral studies six coordinated geometry may be assigned for all the complexes except Co(L)(2)(SO(4)) and Cu(L)(2)(SO(4)) [where L=L(1) and L(2)] which are of five coordinated square pyramidal geometry.     

Copper(II) coordination compounds with 8-quinolinaldehyde semicarbazone: Synthesis and structure

A series of compounds of the general formula Cu(HL)X₂ · nH₂O (compound I, X = ClO₄, n = 3; compound II, X = NO₃, n = 2; compound III, X = Cl, n = 0.5; compound IV, X = 1/2SO₄, n = 0) is isolated by the reactions of the copper(II) salts with quinolinaldehyde semicarbazone (HL). Regardless of the reactant ratio, only the compounds with a metal to ligand mole ratio of 1: 1 are formed, where the organic reactant is coordinated in the molecular form. The X-ray diffraction analyses of the [Cu(HL)(NO₃)(H₂O)](NO₃) · H₂O (II) and [Cu(HL)Cl₂] · 0.5H₂O(III) compounds show their substantially different organizations of the molecular structures depending on the specifics of the acido ligand. An ionic structure with one NO ₃ ^? anion incorporated into the inner coordination sphere of the metal as a bidentate chelate ligand is observed in compound II. Molecular tetragonal pyramidal complexes associated into a dimer due to the bridging function of one coordinated Cl^? anion are formed in structure III. The coordination polyhedron of the copper atom in structures II and III is an asymmetrically extended tetragonal bipyramid. The CuClCu angle equal to 90° and the distance between two planes in compound III equal to 2.978 Å determine the insignificant antiferromagnetic interaction in this compound (g = 2.1, J = ?2.5 cm^?1).     

Copper(II) oxalate and oxamate complexes

Reaction of Cu^II salts with phenanthroline and oxalate (ox) or oxamate (oxm) gives [Cu(phen)(ox)(H₂O)] · H₂O or [Cu(phen)(oxm)(H₂O)] · H₂O complexes while direct treatment of Cu^II salts with oxalate or oxamate gives [NH₄]₂[Cu(ox)₂] and [Cu(oxm)₂(H₂O)₂] respectively. The X-ray structures of one example of each system, aquo-oxamato-phenanthroline-copper(II)-dihydrate and the polymeric ammonium-bis(aquo)-tetraoxalato-dicopper(II)-dihydrate, are reported.     

Nuclease activity of 2-substituted heteroaromatic thiosemicarbazone and semicarbazone copper(II) complexes

Copper(II) Schiff base complexes derived from furan-2-carboxaldehyde, 2-furylmethyl ketone, thiophene-2-carboxaldehyde and methyl-2-thienyl ketone with semicarbazide and thiosemicarbazide have been prepared and characterized by analytical, i.r., electronic, e.s.r. and c.v. spectral data. The electronic spectral d–d band position varies from 744–415nm in pyridine and 872–371nm in DMF. E.s.r. g values lie between 2.1439 and 2.3149 at LNT. All complexes undergo quasi-reversible one-electron electrochemical reduction (Cu^III/Cu^II) in the 0.42–0.52V potential range. The electron transfer is much faster in thiosemicarbazone complexes compared to semicarbazone complexes. All these copper(II) complexes showed increased nuclease activity in presence of oxidant.     

The extraction of ferric chloride with methyl isobutyl ketone and amyl acetate

Summary The extraction of iron as ferric chloride in 7 M hydrochloric acid by a mixture of (1+1) or (2+1) methyl isobutyl ketone and amyl acetate is quantitative for macro as well as for micro amounts of iron. The distribution ratio is very high ( 4000). With these mixtures no emulsification difficulties are encountered as they are with methyl isobutyl ketone alone. The behaviour of 44 elements in this extraction has been investigated.     

Copper(II) and nickel(II) complexes of schiff bases

Summary The isolation of complexes of some nickel(II) and copper(II) salts with the Schiff base derived from 2-aminobenzimidazole and 4-methylbenzaldehyde (abimbz) is reported. They are of the general type M(abimbz)₂X₂ (M=Ni or Cu; X=Cl, Br, or ClO₄). The compounds have been characterized by elemental analyses, conductivity measurements, i.r., electronic and e.p.r. spectral studies and magnetic measurements. The i.r. spectra show that the ligand is bidentate through the tertiary nitrogen of the imidazole ring and the exocyclic imine nitrogen. Possible structures for the complexes are suggested.     

Ionic association of some tetraheptylammonium and tetraoctylphosphonium salts in methyl isobutyl ketone

The extent of ionic association of (hept)₄NCl, (hept)₄NBr, (hept)₄NI, (hept)₄N(NO₃) and (oct)₄P(NO₃) in methyl isobutyl ketone at 55°C has been measured by vapour pressure osmometry with matched thermistors. From the dependence of the osmotic coefficient on the solute concentration the equilibrium constants for ion-pair formation have been obtained for the five quaternary salts. These equilibrium constants are compared with the predictions of Bjerrum's ionic-association model and the Denison-Ramsay-Fuoss model. The latter model required a correction term for the entropy contribution.