Metal(II) complexes and metal(II) salts ofN-carbamoylpyrazole: N,O and N,N coordination

Summary Several new coordination compounds are reported withN-carbamoylpyrazole (Hcpz) as the ligand;viz. M(cpz)₂ where M = Cu^II and Ni^II; M(Hcpz)Cl₂ where M = Mn^II, Co^II, Cu^II, Zn^II and Cd^II; M(Hcpz)₂Cl₂ Where M = Fe^II, Co^II and Ni^II: M(Hcpz)₃(BF₄)₂ where M = Fe^II, Co^II, Ni^II, Zn^II and Cd^II; and Cu(Hcpz)₂(BF₄)₂. In the salts, Hcpz is coordinated through the nitrogen atoms of the pyrazole ring and the nitrogen atom of the carbamoyl group. In the Hcpz complexes, coordination takes place through the nitrogen atom of the pyrazole ring and the oxygen atom of the carbamoyl group.     

Ethers as ligands. Part VI. Transition metal(II) complexes with 18-crown-6

Summary Seven new coordination compounds are reported with the cyclicpolyether 18-crown-6 as the ligand,viz. [Mg(18-crown-6) (H₂O)₂](SbCl₆)₂, [M(18-crown-6)(MeNO₆)₂](SbCl₆)₂ with M is Ca²⁺ and Sr²⁺, [M(18-crown-6)(MeNO₂)](SbCl₆)₂ with M is Mn²⁺ and Co²⁺, and [M(18-crown-6)](SbCl₆)₂ with M is Ni²⁺ and Zn²⁺.     

Mononuclear complexes of manganese(II), iron(II), cobalt(II), nickel(II), copper(II), and zinc(II), with 4-amino-3,5-bis(pyridin-2-yl)-1,2,4 triazole and tris(2-aminoethyl) amine: crystal structure of [Ni(tren)(abpt)](NO3)2(H2O)2.25

Complexes of the type [M(tren)(abpt)](NO₃)₂(H₂O)_n (1–6) [M = Mn^II, Fe^II, Co^II, Cu^II, Zn^II (n = 2), Ni^II (n = 2.25), tren = tris(2-aminoethyl)amine, and abpt = 4-amino-3,5-bis(pyridin-2yl)-1,2,4 triazole] have been prepared. The bonding mode and overall geometry of the complexes have been deduced by elemental analyses, molar conductance values, spectral studies (obtained from FT-IR), ¹H-n.m.r., electronic spectral analyses and magnetic susceptibility measurements. A detailed molecular structure of complex (4) has been determined by single X-ray crystallography.     

Synthesis and characterization of complexes of the first transition series cations with 2,2′-biimidazole and 2,2′-biimidazolate

Mononuclear [M(hfacac)₂(H₂biim)] complexes, where M = Mn^II, Fe^II, Co^II, Ni^II, Cu^II or Zn^II, hfacac = hexafluoroacetylacetonate, H₂biim = 2,2-biimidazole; dinuclear K₂[M₂(acac)₄(-biim)] (M = Cu^II or Zn^II) and tetranuclear K₂[M₄(acac)₈( ₄-biim)] (M = Co^II or Ni^II) complexes have been prepared and characterized by chemical analysis, conductance measurements, i.r., electronic and e.p.r. spectroscopies and by magnetic susceptibility measurements (in the 2–300 K range). Mn^II, Fe^II and Co^II are in a high spin state. The e.p.r. spectra of Cu^II and Mn^II compounds have been recorded.     

Coordination compounds derived from transition metal salts and bis(3,5-dimethylpyrazolyl)methane

Summary The preparation of transition metal complexes containing the sterically hindered ligand, bis(3,5-dimethylpyrazolyl)methane (LL) is described. Compounds of formula M(LL)X₂ (M = Co^II, Ni^II or Zn^II and X = Cl^– or Br^–) or M(LL)₂X₂ (M = Mn^II, Fe^II, Co^II, Ni^II, Cu^II, Zn^II or Cd^II and X = ClO ₄ ^– ; M = Co^II, Ni^II, Cu^II or Zn^II and X = NO ₃ ^– ; M = Ni^II or Cu^II and X = Cl^– or Br^–) have been isolated. In addition, an apparently trimeric Cu₃(LL)₄Cl₆ · EtOH compound is reported. For Ni(LL)Cl₂ a five-coordinated chloro-bridged dimer is found. The perchlorato compounds, M(LL)₂(ClO₄)₂, appear to have one bidentate ClO ₄ ^– and one ionic ClO ₄ ^– group. The M(LL)₂ species appears to occur either in octahedral geometry, leaving twocis-positions free, or in a tetrahedral geometry without space for other ligands, and probably also in a five-coordinate geometry with one free ligand position.Structural conclusions are drawn from i.r., far-i.r. and ligand-field spectra, x-ray powder patterns, magnetic susceptibility data, e.s.r. spectra and conductivity data.     

Studies on 4-(2-thiazolyl)-1-(2,6-diacetylpyridine)thiosemicarbazone complexes of some bivalent metal ions

Summary Complexes of 4-(2-thiazolyl)-1-(2,6-diacetylpyridine)-thiosemicarbazone, H₂C₃NSCNH(S)NHNCMeC₅H₃N-C(O)Me (Htdaptsc) of the compositions [M(Htdaptsc)₂Cl₂] [M=Mn^II, Co^II, Ni^II or Zn^II] [M(Htdaptsc)Cl₂] [M=Zn^II, Cd^II or Hg^II] and [M(tdaptsc)₂] [M=Mn^II, Co^II, Ni^II, Cu^II, or Zn^II] have been prepared and characterized by elemental analyses, molar conductance, magnetic susceptibility, electronic, e.s.r. and i.r. studies, and their stereochemistries are discussed.     

Nitrates and bis(dithiooxalato)nickelates(II) of biacetyldihydrazone complexes

Summary Biacetyldihydrazone (BdH) complexes [M(BdH)₃](NO₃)₂ (M=Co^II, Ni^II, Cu^II or Zn^II); [Fe(BdH)₃](NO₃)₃; [M(BdH)₃][Ni(dto)₂] (M=Co^II, Ni^II or Zn^II; dto=dithiooxalate); [Cu(BdH)₂][Ni(dto)₂] and [Fe(BdH)₃]₂[Ni(dto)₂]₃ have been prepared and characterized by chemical analysis, conductance measurements, electronic and i.r. spectral studies and cyclic voltammetry.A mononuclear octahedral configuration is proposed for all cationic complexes, excepting [Cu(BdH)₂][Ni(dto)₂, which is probably a dithiooxalate bridged dimer.     

Ligational behaviour of biacetylmonoxime nicotinoyl hydrazone (H2BMNH) towards transition metal ions

Summary The synthesis and characterization of Mn^II, Co^II, Ni^II, Cu^II, Zn^II, Cd^II UO ₂ ²⁺ , Cr^III and Fe^III complexes of biacetylmonoxime nicotinoyl hydrazone (H₂BMNH) are reported. Elemental analysis, molar conductance, magnetic moment and spectral (i.r., visible and n.m.r.) measurements have been used to characterize the complexes. I.r. spectral data show that the ligand behaves in a bidentate and/or tridentate manner. An octahedral structure is proposed for the Mn^II, Ni^II, Cr^III and Fe^III complexes, while a square-planar structure is proposed for both Co^II and Cu^II complexes on the basis of magnetic and spectral measurements.     

Metal complexes of ethylenediaminetetraacetamide

Summary A convenient synthesis of the ligand ethylenediaminetetraacetamide (L) is described, and a number of metal complexes of the general formula MLCl_n · xH₂O (Mⁿ⁺=Ca^II, Mn^II, Fe^II, Co^II, N^II, Cu^II, Zn^II, Mg^II, Ba^II, Cd^II, Hg^II and La^III) prepared. The deprotonated Cu(L-H)₂ · 2 H₂O complex has been characterised and the associated pK values determined. I.r., conductivity, magnetic susceptibility and electronic spectral data are discussed.     

Isonitrosoacetylacetone dithiosemicarbazone complexes of some first row transition metals

Summary Complexes of the potentially tetradentate ligand isonitroso-acetylacetone dithiosemicarbazone (inbtH₂) of formulae [Ti(inbtH₂)Cl₂]Cl₂, [M(inbt)], where M = V^IV O, Mn^II, Ni^II or Zn^II, [M(inbtH₂)X₂], where M = Co^II and X = Cl, or M = Ni^II and X = Cl, Br or I, and [M(inbtH₂)Cl₂]Cl, where M = Cr^III or Fe^III, have been prepared and characterized by physico-chemical and spectroscopic methods. In all the compounds the metal is coordinated by the thiocarbonyl sulphur and imine nitrogen, as revealed by i.r. studies. The n.m.r. spectra of the complexes of Ni^II and Zn^II confirm coordination through nitrogen. Possible structures for the complexes are proposed. The Mössbauer spectrum of the Fe^III complex is discussed.     

New complexes of iron(III), cobalt(II), nickel(II) and copper(II) with 2-phenyl-1,2,3-triazole-4-carboxalidene-2-aminophenol

Summary Fe^III, Co^II, Ni^II and Cu^II complexes of a new Schiff base, 2-phenyl-1,2,3-triazole-4-carboxalidene-2-aminophenol (PTCAP), have been synthesized and characterized by elemental analyses, molar conductance and magnetic susceptibility measurements, and by u.v.-vis., i.r. and e.p.r. spectral observations. The studies indicate an octahedral structure for the complexes with the general formula [ML₂] (M = Co^II, Ni^II or Cu^II.; L = PTCAP) or [M′(OH)L₂] (M′ = Fe^III). The i.r. spectra suggest that the ligand acts as a tridentate (NNO) donor towards Co^II, Ni^II and Cu^II, and, in the Fe^III complex, one of the two ligand molecules acts as a bidentate (NO) donor and the other as a tridentate donor. The M?ssbauer spectrum of the Fe^III complex suggests the presence of a spin equilibrium at room temperature. Cyclic voltammograms are also recorded for the Cu^II and Fe^III complexes.     

Magnetic properties of biacetyldihydrazone complexes

Summary Magnetic susceptibilities of the biacetyldihydrazone (BdH) complexes [M(BdH)₃](NO₃)₂ (M = Co^II, Ni^II, Cu^II or Zn^II), [Fe(BdH)₃](NO₃)₃, [M(BdH)₃](Ni(dto)₂] (M = Co^II, Ni^II or Zn^II; dto = dithiooxalate), [(BdH)₂Cu(dto)Ni(dto)] and [Fe(BdH)₃]₂[Ni(dto)₂]₃ have been studied in the 4.2–295 K range. Zn^II complexes are diamagnetic, and complexes of Ni^II, Cu^II and Fe^III obey the Curie-Weiss law. The Co^II complexes behave anomalously and the results are interpreted in terms of a high spinlow spin equilibrium.     

Cation exchange behaviour of mercury (II) on Dowex 50W-X8

Summary Quantitative studies are reported on the behaviour of mercury at milligram level, using cation exchange resin Dowex 50W-X8. Various eluants such as nitric acid, hydrochloric acid, sulphuric acid, ammonium acetate, sodium nitrate solutions, sodium nitrate-nitric acid mixtures, ammonium acetate-acetic acid mixture are used for column operation. The elution constants are evaluated. Mercury(II) is separated from different cations, i.e., Ca²⁺, Ba²⁺, Sr²⁺, Mg²⁺, Fe³⁺, Al³⁺, Co²⁺, Ni²⁺, Zn²⁺, Cu²⁺ by selective elution.

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Zusammenfassung Das Verhalten von mg-Mengen Quecksilber am Kationenaustauscher Dowex 50W-X8 wird quantitativ untersucht. Dabei werden folgende Eluierungsmittel benutzt: Salpetersäure, Salzsäure, Schwefelsäure, Lösungen von Ammoniumacetat und Natriumnitrat sowie die Gemische Salpetersäure-Natriumnitrat und Essigsäure-Ammoniumacetat. Die Elutionskonstanten werden berechnet. Durch selektive Eluierung kann Quecksilber von mehreren Kationen (Ca²⁺, Ba²⁺, Sr²⁺, Mg²⁺, Fe³⁺, Al³⁺, Co²⁺, Ni²⁺, Zn²⁺, Cu²⁺) getrennt werden.

     

Complexes of 1-isonicotinoyl-4-benzoyl-3-thiosemicarbazide with manganese(II), iron(III), chromium(III), cobalt(II), nickel(II), copper(II) and zinc(II)

1-Isonicotinoyl-4-benzoyl-3-thiosemicarbazide (IBtsc) and its Cr^III, Mn^II, Fe^III, Co^II, Ni^II, Cu^II and Zn^II complexes have been prepared and characterized by elemental analyses, magnetic susceptibility measurements, u.v.–vis., i.r., n.m.r. and FAB mass spectral data. The room temperature e.s.r. spectra of the Cr^III, Fe^III and Cu^II complexes yield values, characteristic of octahedral, tetrahedral and square-planar complexes, respectively. The Mössbauer spectra of [Fe(IBtsc-H)Cl₂] at room temperature and at 78 K suggest the presence of high-spin Fe^III. The Ni^II, Cr^III and Cu^II complexes show semiconducting behaviour in the solid state, but the Zn^II complex is an insulator at room temperature. IBtsc and its soluble complexes have been screened against several bacteria, fungi and tumour cell lines.     

Ligational behaviour of a tetradentate NONS donor ligand towards some transition metal ions

Summary The synthesis and characterization of Cr^II, Mn^II, Fe^II, Co^II, Ni^II, Pd^II, Cu^II, Zn^II, Cd^II and UO ₂ ²⁺ complexes of 1-meotinoyl-4-phenyl-3-thiosemicarbazide (H₂NTS) are reported. I.r. spectral data show that the ligand behaves in a bidentate and/or tetradentate manner. An octahedral structure is proposed for the Cr^II, Fe^II and Ni^II complexes; a tetrahedral structure for the Mn^II, Co^II and Cu(NTS)·2H₂O complexes; and a square planar structure for the Pd^II and Cu(HNTS)Cl·H₂O complexes. The i.r. data suggest that the Fe^II complex contains a hydroxo bridge.     

Studies on 4-(2-thiazolyl)-1-(2-acetylpyridine)thiosemicarbazone complexes of some bivalent metal ions

Summary Complexes [VO(Htaptsc)SO₄] and [M(Htaptsc)₂Cl₂] [M=Mn^II, Ni^II, Cd^II or Hg^II], Cu(Htaptsc)Cl₂ and [M(Htaptsc)Cl₂] [M=Co^II or Zn^II], and deprotonated compounds Co(taptsc)₂ and [M(taptsc)₂] [M=V^IVO, Mn^II, Ni^II, Cu^II or Zn^II] [Htaptsc=4-(2-thiazolyl)-1-(2-acetylpyridine)thiosemicarbazone] have been characterized by elemental analyses, electrical conductivity and magnetic susceptibility measurements and electronic, e.s.r. and i.r. spectroscopy. The bonding sites of Htaptsc and the bonding and stereochemistry of the complexes are discussed.     

Thermal decomposition of dinuclear complexes LM(μ-OOCR)<Subscript>4</Subscript>ML (L is α-substituted pyridine)

The solid-state thermal decomposition of the tetrabridged dinuclear Mn^II, Fe^II, Co^II, Ni^II, and Cu^II pivalate complexes with apical α-substituted pyridine ligands containing different substituents (2,3-dimethylpyridine or quinoline) was studied by differential scanning calorimetry and thermogravimetry. The decomposition of the Co^II complexes is accompanied by the aggregation to form the volatile octanuclear complex Co₈(μ₄-O)₂(μ_n-OOCCMe₃)₁₂, where n = 2 or 3, whereas the thermolysis of the Mn^II, Fe^II, Ni^II, and Cu^II complexes is accompanied by the degradation of the starting compounds, the phase composition of the decomposition products being substantially dependent on the nature of metal and the apical organic ligand. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1650–1659, September, 2007.     

Transition metal complexes derived from N-isonicotinamido-N′-benzoylthiocarbamide (H2IBTC)

Summary The synthesis and characterization of Cr^III, Mn^II, Fe^III, Co^II, Ni^II, Cu^II, Zn^II, Cd^II and UO _inf2 ^sup2+ complexes of N-isonicotinamido-_N-benzoylthiocarbamide (H₂IBTC) are reported. I.r. spectral data show that the ligand behaves in a bidentate, tridentate and/or tetradentate manner. Different stereochemistries are proposed for Cr^III, Mn^II, Fe^III, Co^II, Ni^II and Cu^II complexes on the basis of spectral and magnetic studies. The i.r. data indicate that the carbonyl oxygen of the benzoyl moiety is the backbone of chelation in most complexes.     

Thermal decomposition of dinuclear complexes LM(μ-OOCR)<Subscript>4</Subscript>ML (L is α-substituted pyridine)

The solid-state thermal decomposition of the dinuclear pivalate complexes LM(μ-OOCR)₄ML, both those synthesized earlier (M = Mn^II, Fe^II, or Co^II; L = 2,6-(NH₂)₂C₅H₃N)) and new complexes (M = Cu^II; L = 2,6-(NH₂)₂C₅H₃N or (2-NH₂)(6-CH₃)C₅H₃N), was studied by differential scanning calorimetry and thermogravimetry. The decomposition of the Co^II complexes is accompanied by the aggregation to form the volatile octanuclear complex Co₈(μ₄-O)₂(μ_n-OOCCMe₃)₁₂ (n = 2 or 3), whereas the thermolysis of the Mn^II, Fe^II, and Cu^II complexes is destructive, the phase composition of the decomposition products being substantially dependent on the nature of metal and the α substituent R in the apical organic ligand.     

Studies on 2-aminobenzophenone-2-thenolhydrazone complexes of some bivalent transition metal ions

Summary Complexes having the chemical compositions [VO(Habth)₂SO₄], [M(Habth)₂Cl₂] [M=Co^II, Ni^II, Cu^II or Zn^II) and [M(abth)₂] [M=V^IVO, Co^II, Ni^II, Cu^II or Zn^II) and Habth=2-aminobenzophenone-2-thenoylhydrazone] have been prepared and characterized. The complexes are non-electrolytes. Magnetic moments and electronic, photoacoustic, e.s.r. and i.r. spectra of the complexes are used to establish the stereochemistry and mode of bonding of the hydrazone.