Characteristic features of decomposition of potassium pentacyano-cobaltates(III) on a bombardment with fast atoms

Mass spectra were obtained of cobalt(III) pentacyanide complexes of the K_n[Co(CN)₅X] type bombarded by fast atoms, where X = H₂O, NO₂ ^–, NO^–. The ligand elimination processes from the coordination sphere of the pentacyanides and the redox reactions of the complexes were studied.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 28, No. 2, pp. 173–176, March–April, 1992.     

Halogen-und Pseudohalogenkomplexe von Kobalt(II) in Nitromethan

Zusammenfassung Die neutralen Halogenide und Pseudohalogenide von Kobalt(II) sind in Nitromethan kaum dissoziiert. Bei Zusatz entsprechender Anionen zu Kobalt(II)-perchloratlösungen werden in Nitromethan folgende Koordinationsformen leicht gebildet: CoCl₂, CoCl₃ ^–, CoCl₄ ^2–, CoBr₂, CoBr₃ ^–, CoBr₄ ^2–, CoJ₂, CoJ₃ ^–, CoJ₄ ^2–, Co[N₃]₂, [Co(N₃)₄]^2–, Co[NCS]₂, [Co(NCS)₄]^2–, Co[CN]₂ [Co(CN)₄]^2– und [Co(CN)₅]^3–.

---

The neutral halides and pseudohalides of cobalt(II) are nearly undissociated in nitromethane. On addition of the appropriate anion to a solution of cobalt(II)-perchlorate in nitromethane the following coordination forms are easily produced: CoCl₂, CoCl₃ ^–, CoCl₄ ^2–, CoBr₂, CoBr₃ ^–, CoBr₄ ^2–, CoJ₂, CoJ₃ ^–, CoJ₄ ^2–, Co[N₃]₂, [Co(N₃)₄]^2–, Co[NCS]₂, [Co(NCS)₄]^2–, Co[CN]₂, [Co(CN)₄]^2– and [Co(CN)₅]^3–.

---

---

Mit 10 Abbildungen     

Cobalt(II) complexes of 1,2-(diimino-4′-antipyrinyl)ethane and 4-N-(4′-antipyrylmethylidene)aminoantipyrine

Cobalt(II) complexes of the Schiff bases 1,2-(diimino-4-antipyrinyl)ethane (GA) and 4-N-(4-antipyrylmethylidene)aminoantipyrine (AA) have been prepared and characterised by elemental analysis, electrical conductance in non-aqueous solvents, i.r. and electronic spectra, as well as by magnetic susceptibility measurements. The complexes have the general formulae [Co(GA)X]X (X = ClO^– ₄ or NO₃ ^–), [Co(GA)X₂] (X = Cl^–, Br^– or I^–), [Co(AA)₂]X₂ (X = ClO₄ ^–, NO₃ ^–, Br^– or I^–) and [Co(AA)Cl₂]. GA acts as a neutral tetradentate ligand, coordinating through both carbonyl oxygens and both azomethine nitrogens. In the perchlorate and nitrate complexes of GA one anion is coordinated in a bidentate fashion, whereas in the halide complexes both anions are coordinated to the metal, generating an octahedral geometry around the Co ion. AA acts as a neutral bidentate ligand, coordinating through the carbonyl oxygen derived from the aldehydic moiety and the azomethine nitrogen. Both anions remain ionic in the perchlorate, nitrate, bromide and iodide complexes of AA, whereas both anions are coordinated to the metal ion in the chloride complex, resulting tetrahedral geometry around the Co ion.     

Paper chromatographie studies on periodic precipitation

Summary An investigation of the nature of the rhythmic patterns obtained by diffusing the reactant solution on the circular filter papers impregnated with precipitating agents and a protective colloid (2% agar agar) has been made. The systems: AgNO₃–K₂CrO₄, Pb(NO₃)₂–K₂CrO₄, Ba(NO₃)₂–K₂CrO₄, Co(NO₃)₂–K₄Fe(CN)₆, and Co(NO₃)₂–K₃Fe(CN)₆ have been studied. An attempt has been made to explain the radial and ring rhythmicity on filter papers on the basis of coagulation theory ofDhar andChatterji.     

Hexamethylphosphorsäuretriamid als Ligand, 3. Mitt.: Umsetzungen von [Co(HMPT)4]2+ mit Rhodanid-, Cyanid- und Azidionen

Zusammenfassung Auf Grund spektrophotometrischer, potentiometrischer und konduktometrischer Befunde entstehen aus [Co(HMPT)₄]²⁺ in Hexamethylphosphorsäuretriamid (HMPT) bei Zusatz von Pseudohalogenidionen folgende Koordinationsformen: [Co(HMPT)₃N₃]⁺, [Co(HMPT)₂(N₃)₂], [Co(HMPT)(N₃)₃]^–, [Co(N₃)₄]^2–, [Co(HMPT)₃NCS]⁺, [Co(HMPT)₂(NCS)₂], [Co(HMPT)(NCS)₃]^–, [Co(NCS)₄]^2–, [Co(HMPT)₂(CN)₂], [Co(HMPT)(CN)₃]^–, [Co(HMPT)(CN)₅]^3–.

---

Hexamethyl phosphoric triamide as a ligand, III: Reactions of [Co(HMPT)₄]²⁺ with rhodanide, cyanide, and azide ions, resp

Spectrophotometric, potentiometric and conductometric results indicate that addition of pseudohalide ions to [Co(HMPT)₄]²⁺ in hexamethylphosphoramide (HMPT) leads to the following coordination forms: [Co(HMPT)₃N₃]⁺, [Co(HMPT)₂(N₃)₂], [Co(HMPT)(N₃)₃]^–, [Co(N₃)₄]^2–, [Co(HMPT)₃NCS]⁺, [Co(HMPT)₂(NCS)₂], [Co(HMPT)(NCS)₃]^–, [Co(NCS)₄]^2–, [Co(HMPT)₂(CN)₂], [Co(HMPT)(CN)₃]^–, [Co(HMPT)(CN)₅]^3–.

---

---

Mit 7 Abbildungen

---

2. Mitt.:V. Gutmann undA. Weisz, Mh. Chem.100, 2104 (1969).     

Determination of the calibration constant of the isomer shift of 57Fe Mössbauer spectra

Results are presented from quantum-chemical calculations for the iron complexes Fe(CN)₅NO^2–, Fe(CN)₆ ^3–,Fe(CN)₆ ^4–, FeCl₄ ^–, and FeCl₆ ^3– in comparison with Mössbauer-spectroscopic data. The parameters of the Mössbauer spectra were calculated according to specially developed programs. The calibration constant of the isomer shift was determined to be –0.13 mm/sec.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 23, No. 4, pp. 506–508, July–August 1987.     

Osmotic coefficients of dilute aqueous solutions of unsymmetrical cobalt-amine type salts at 0°C

The osmotic coefficients of dilute aqueous solutions of [Co(pn)₃]X₃ [pn=1,2-diaminopropane and X=Cl^–, Br^– and (NO₃)^–] and [Co(tn)₃]X₃ (tn=1,3-diaminopropane and X=Cl^– and Br^–) have been measured from 0.00 to 0.02 mol-kg^–1 at 0°C by the freezing point method. The results have been compared with those obtained from the numerical integration of the Poisson-Boltzmann equation.     

Transition metal complexes of amidinourea and related ligands,part 3. Mixed ligand complexes of cobalt(III) containing biguanide,O-methyl-l-amidinourea and some bidentate ON and NN donor ligands

Summary New cobalt(III) complexes of general formula [Co(AA)(bigH)₂ ]X₃ and [Co(amidinourea)(MAUH)₂ ]X₃ where AA = amidinourea,N-phenylsalicylideneimine, bigH = biguanide, MAUH =O-methyl-l-amidinourea, X = 0.5 [SO₄]^2–, CI^–, Br^– or 0.33 [Co(NO₂)₆ ]^3– have been synthesized and characterized. Conductance measurements (aqueous solution) show [Co(amidinourea)(bigH)₂]Cl₃ and [Co(N-phem,lsalicylideneimine)(bigH)₂]CI₃ to be triunivalent.Author to whom correspondence should be addressed.     

Dinuclear complexes with a μ-cyano ligand. Part XI(1). Synthesis and characterization of several derivatives ofcis-[Co(NH3)(en)2(H2O)]3+

Summary The new complex double saltscw-[Co(NH₃)(en)₂(H₂O)]₂ [M(CN)₄]₃ (en = ethylenediamine; M = Ni, Pd or Pt),cis-[Co(NH₃(en)₂(H₂O)]₂[FeNO(CN)₅]₃ andcis-[Co(NH₃)(en)₂(H₂O)][Co(CN)₆] have been synthesized and by anation in the solid state the corresponding new dinuclear complexes with a cyano bridgecis- ortrans-[(NH₃)(en)₂Co-NC-M(CN)₃]₂ [M(CN)₄] (M = Ni, Pd or Pt);cis-, trans-[(NH₃)(en)₂Co-NC-FeNO(CN)₄]₂[FeNO(CN)₅] andcis-[(NH₃)(en)₂Co-NC-Co(CN)₅ have been prepared. The complexes have been characterized by chemical analysis, t.g. measurements, and by i.r. and electronic spectroscopy. With [Ni(CN)₄][^2– and [Co(CN)in]₆ ^3– only thecis-isomer is produced; with [Pd(CN)₄]^2–, [Pt(CN)₄]^2– and [FeNO(CN)₅]^2– thetrans- isomer is the dominant species. The dinuclear complex derived from [Pt(CN)₄]^2– shows strong Pt-Pt interactions both in the solid state and in solution.     

Trans influence and charge transfer transitions X → Co in cobalt (III) complexes of the type trans [CO(en)2XY]z

The energies of the CT transitiopns X → Co have been measured for a series of compounds of the type trans [CO(en)₂XY]^+z, with X = Cl, Br and Y = Cl, Br, NH₃, OH, NCS, No₂, SO₃, CN. They depend upon the nature of the Yl igand. Values of the optical electronegativity of the CO d_z2 orbitals have been calculated, showing that the covalent character of the CoX bond increases in the following order of the Y ligands: NCS ≈ NH₃ ≈CN < OH < NO₂ < Cl ≈ Br < SO₃. This result is discussed along with the variations of the Co bonding forces.     

A spectroscopic study of cobalt(III) furyldioximates

Summary The electronic properties of a series of cobalt(III)trans-furyldioximato-complexes of the type [CoB(FH)₂X] (B=NH₃, X=Cl, Br, I or NO₂; B=pyridine (py) or thiocarbamide (thio), X=Cl or Br; B=imidazole (imid), X=Br), [Co(FH₂)(FH)Cl₂] and [Co(thio)₂(FH)₂]NO₃ were studied by i.r., u.v. and¹H and¹³C n.m.r. spectra The results were compared with those from the corresponding dimethylglyoximato-complexes. It was concluded that -conjugation over the equatorial plane in the furyldioximates is greater than in the dimethylglyoximates. There is some evidence of thetrans-influence of the anionic ligands in the ammines which are in the order NO ₂ ^– >Br^–>Cl^–.     

Cobalt(II) nitrate complexes with piperidin-4-ones

Ten cobalt(II) nitrate complexes with variously substituted 2,6-diphenylpiperidin-4-ones (L¹)–(L¹⁰) have been prepared and characterized by elemental analysis, molecular weight determination, molar conductance and magnetic, thermal, polarographic and spectral studies. The formula [Co(L)₂(H₂O)₄](NO₃)₂ has been assigned to complexes (2–5), (7), (8) and (10) and [Co(L)₂(H₂O)₂(NO₃)]NO₃ to complexes (1), (6) and (9). Although piperidin-4-ones have two coordinating sites, namely the ring nitrogen and the carbonyl group, i.r., and polarographic studies indicate that only the ring nitrogen is involved in coordination. Electronic spectral data reveal that these complexes have octahedral geometry.     

Analytical application of atomic emission and atomic absorption spectrometry for the determination of imidazoline derivatives based on formation of ion-associates with sodium cobaltinitrite and potassium ferricyanide

Ion-association complexes of Naphazoline HCl (I), Tolazoline HCl (II) and Xylometazoline HCl (III) with [Co(NO₂)₆]^3– and [Fe(CN)₆]^3– were precipitated and the excess of the unreacted iron or cobalt comples was determined. A new method using atomic emission and atomic absorption spectrometry for the determination of the above drags in pure solutions and in pharmaceutical preparations is given. The drugs have been determined in the ranges 0.98–14.76, 0.78–11.80 and 1.12–16.80 g/ml solutions of I, II and III. respectively, using [Co(NO₂)₆]^3–], with mean relative standard deviations of 0.4–1.5% and 1.92%–19.68, 1.52–5.68 and 2.24–22.4 g/ml solutions of I, II and III, respectively using [Fe(CN)₆]^3– with mean relative standard deviations of 0.6–1.6%. The recovery values of 98.12–101.26% indicate high precision and accuracy.     

Kinetics and mechanism of pentacyanohydroxoferrate(III) formation from mono(aminocarboxylato)iron(III) complexes

Summary The kinetics and mechanism of the system: [FeL(OH)]^2–n + 5 CN^– [Fe(CN)₅(OH)]^3– + L^n–, where L=DTPA or HEDTA, have been investigated at pH= 10.5±0.2, I=0.25 M and t=25±0.1 C.As in the reaction of [FeEDTA(OH)]^2–, the formation of [Fe(CN)₅(OH)]^3– through the formation of mixed ligand complex intermediates of the type [FeL(OH)(CN)_x]^2–n–x, is proposed. The reactions were found to consist of three observable stages. The first involves the formation of [Fe(CN)₅(OH)]^3–, the second is the conversion of [Fe(CN)₅(OH)]^3– into [Fe(CN)₆]^3– and the third is the reduction of [Fe(CN)₆]^3– to [Fe(CN)₆]^4– by oxidation of L^n– The first reaction exhibits a variable order dependence on the concentration of cyanide, ranging from one at high cyanide concentration to three at low concentration. The transition between [FeL(OH)]^2–n and [Fe(CN)₅(OH)]^3– is kinetically controlled by the presence of four cyanide ions around the central iron atom in the rate determining step. The second reaction shows first order dependence on the concentration of [Fe(CN)₅(OH)]^3– as well as on cyanide, while the third reaction follows overall second order kinetics; first order each in [Fe(CN)₆]^3– and L^n–, released in the reaction. The reaction rate is highly dependent on hydroxide ion concentration.The reverse reaction between [Fe(CN)₅(OH)]^3– and L^n– showed an inverse first order dependence on cyanide concentration along with first order dependence each on [Fe(CN)_5– (OH)]^3– and L^n–. A five step mechanism is proposed for the first stage of the above two systems.     

Bacterial activity of cobalt(III) complexes. Part IV: Diethylenetriaminemonoacetatocobalt(III) complexes

Summary The activities of the diethylenetriaminemonoacetatocobalt(III) complexes, [Co(en)(DTMA)]I₂, [CoX₂(DTMA)] and [CoCO₃(DTMA)]·H₂O (DTMA=diethylenetriaminemonoacetato or formally 3-amino-3, 6-diazaoctanato; en=ethylenediamine, X=Cl^–, NO ₂ ^– , NCS^–) were studied onEscherichia coli B growing in a minimal glucose medium in both lag- and log-phases. Activities decrease in the order: [Co(NCS)₂(DTMA)]> [Co(NO₂)₂(DTMA)]>[Co(en)(DTMA)]I₂>[CoCl₂(DTMA)] >[CoCO₃(DTMA)]·H₂O. The antagonistic activities of the complexes were also studied.     

Coordination chemistry of poly(1-pyrazolyl)alkanes Part V: Preparation and characterization of cobalt(II) complexes with bis(1-pyrazolyl)methane and bis(3-methylpyrazolyl)propane

Summary Bis(1-pyrazolyl)methane, H₂Cbpz, and bis(3-methylpyrazolyl)propane, Me₂Cbmpz, react with cobalt(II) salts to give the solid complexes: [Co(H₂Cbpz)₂X₂] ·2H₂O (X=Cl^–, Br^–, I^–, NO ₃ ^– or ClO ₄ ^– ) and [Co(Me₂-Cbmpz)X₂] (X=Cl^–, Br^–, or I^–), which were isolated and characterised by elemental analysis, i.r. and electronic spectra and conductance measurements. From spectral data, octahedral and tetrahedral structures have been proposed for the H₂Cbpz and Me₂Cbmpz complexes respectively. The molar conductance of the complexes indicates that they are non-ionic.     

Trennung einiger Kationen und Anionen mit dem Ringofen

Zusammenfassung Ein systematischer Trennungsgang von Fe(III), Ni(II), Cd(II), Co(II), Cu(II), Al(III), SO₄ ^2–, Cl^– und NO₃ ^– unter Anwendung des Ringofens wird beschrieben.

---

Separation of some cations and anions by the ringoven technique

Summary The systematic separation of Fe(III), Ni(II), Cd(II), Co(II), Cu(II), Al(III), SO₄ ^2–, Cl^– und NO₃ ^– by the ringoven-method is described.

     

Vibrational spectroscopy and solid-state MAS NMR studies of mercury(II) acetate complexes [Hg(X)OAc]: Crystal structure of [Hg(CN)OAc]

The syntheses of [Hg(X)OAc] (OAc=acetate; X=CN, Cl, Br, I, SCN) are reported, and the crystal structure of the cyano complex has been determined. The asymmetric unit contains two [Hg(CN)OAc] molecules which show almost linear C–Hg–O bonding (Hg–C=2.019(13), 2.016(11) Å; Hg–O=2.067(9), 2.058(8) Å; C–Hg–O=176.0(4), 172.3(5)°), with only one of the two acetate oxygen atoms bound directly to the mercury atom. Secondary HgO and HgN contacts in the range 2.6–2.8 Å are about 0.2 Å shorter than the secondary HgO contacts in the corresponding X=Ph complex. The ν(HgX) and ν(HgO) modes have been assigned in the IR and Raman spectra of [Hg(X)OAc] (X=CN, Cl, Br, I, SCN); these spectra show that the complexes have structures with essentially linear O–Hg–X bonding, similar to that of the cyanide. Solid-state ¹⁹⁹Hg MAS NMR spectra have been recorded for HgX₂ (X=CN, Cl) and [Hg(X)OAc] (X=Me, Ph, CN, Cl, SCN), and spinning sideband analysis has been used to determine the ¹⁹⁹Hg shielding anisotropy and asymmetry parameters Δσ and η. A semi-empirical method for the calculation of the local paramagnetic contribution to the shielding is given, and a linear relationship between Δσ and the isotropic shielding σ_iso which is predicted by this model for linear HgXY species is found to be obeyed reasonably well by the experimental data for HgX₂ and [Hg(X)OAc]. The same method is used to analyse the effects of secondary bonding on the ¹⁹⁹Hg shielding parameters. The ¹³C MAS NMR spectrum of [Hg(SCN)OAc] shows ²J(¹⁹⁹Hg¹³C) and ³J(¹⁹⁹Hg¹³C) coupling to the acetate carbon atoms, with magnitudes similar to those found previously for Hg(OAc)₂. The CN carbon signals in Hg(CN)₂ and [Hg(CN)OAc] are split into 2:1 doublets due to residual dipolar coupling to the quadrupolar ¹⁴N nucleus.     

Kinetics and mechanism of pentacyanohydroxoferrate(III) formation from [FeL(OH)2]− complex, (L=N-(2-hydroxyethyl) iminodiacetate anion

Summary The kinetics and mechanism of the system [FeHIDA-(OH)₂]^–+5CN^–[Fe(CN)₅OH^–+HIDA^2–+OH^– (HIDA=N-(2-hydroxyethyl) (iminodiacetate) at pH=9.5±0.02, I=0.1 M and at 25±0.1°C have been studied spectrophotometrically at 395 nm ( _max of [Fe(CN)₅OH]^3–]. The reaction has three distinguishable stages; the first is formation of [Fe(CN)₅OH]^3–, the second is conversion of [Fe(CN)₅OH]^3– into [Fe(CN)₆]^3–, and last is the reduction of [Fe(CN)₆]^3– to [Fe(CN)₆]^4– by the HIDA^2– released in the first stage. The first stage shows variable-order dependence on cyanide concentration, unity at high cyanide concentration and zero at low cyanide concentration. The second stage exhibits first-order dependence on the concentration of [Fe(CN)₅OH]^3– as well as on cyanide. The reverse reaction between [Fe(CN)₅OH]^3– and HIDA^2– is first-order in each of these species and inverse first-order in cyanide. On the basis of forward and reverse rate studies, a five-step mechanism has been proposed for the first stage. The first step involves a slow loss of one OH^–, by a cyanide-independent path.     

Vibrational spectral studies of ion-ion and ion-solvent interactions. III. Zinc nitrate in water/acetonitrile mixtures

Raman and some infrared line parameters of Zn(NO ₃ ) ₂ /H ₂ O/CH ₃ CN systems spanning a range of both solute and mixed solvent compositions are reported. It is concluded that the first cosphere of the zinc cation contains H ₂ O, CH ₃ CN, and NO ₃ ^–, the relative amounts of which are dependent on the composition. From an intensity analysis the relative amounts of these species in the first cosphere have been obtained. As the CH ₃ CN/H ₂ O ratio increases, a signal at 2263 cm ^–1 , attributed to CH ₃ CN in the second cosphere binding to water in the first cosphere, increases. For a solvent composition of 4 moles water to 1 mole acetonitrile, an ion-pair association constant for Zn ²⁺ (NO ₃ )^– of 0.090 M ^–1 (25°C) was measured. Evidence that the tetrahedral four-coordinate species [Zn(NO ₃ ) ₂ (CH ₃ CN) ₂ ] is the major constituent in acetonitrile-rich mixed solvents is presented.