Complexes of 4-hydroxyphenylthiocarboxyhydrazide with iron(II), cobalt(II,III), nickel(II), copper(II) and zinc(II)

Summary The 4-hydroxyphenylthiocarboxyhydrazide (Hoth) ligand has been characterized by i.r.,¹H and¹³C spectral studies. Its metal complexes with Fe^II, Co^II,III, Ni^II, Cu^II and Zn^II have been prepared and characterized on the basis of elemental analyses, molar conductance, magnetic susceptibility. Mössbauer, visible, e.s.r., i.r.,¹H and¹³C n.m.r. spectral studies. The bonding and stereochemistry of the complexes are discussed. Hoth and its Cu^II complexes have been screened towards bacteria, viruses and fungi.     

Complexes of cobalt(II), nickel(II), copper(II), zinc(II) and manganese(II) with tridentate Schiff base ligand

Summary A series of metal complexes with new tridentate Schiff base derived from salicylaldehyde and furfuraldehyde with o-phenyldiamine have been prepared and characterised by physical and chemical methods. Electronic spectra, room temperature magnetic moment values, e.p.r. and X-ray photoelectron spectroscopy studies suggest an octahedral geometry for all the complexes, where low molar conductance values are in accord with their non-electrolytic nature. The thermal stability of the complexes is discussed and the ligand-to-metal bonding modes discussed.     

Metal complexes of anti-inflammatory drugs—I. Complexes of iron(III), cobalt(II), nickel(II), copper(II) and zinc(II) with 4-hydroxy-3-(5-methyl-3-is

The preparation, spectroscopic and magnetic properties are reported for complexes of iron(III), cobalt(II), nickel(II), copper(II) and zinc(II) with th     

Complexes of copper(II), nickel(II) and cobalt(II) with 4-fluoro, 3-nitroaniline

Complexes of the type M(4-F3-NA)_nX₂·mH₂O (where M = Cu (II), Ni (II), Co (II); 4-F3-NA = 4-fluoro, 3-nitroaniline; (n = 1–4; X = Cl, Br, SCN, ClO₄; m= 0–4) have been studied by i.r. and electronic spectroscopy, magnetic and conductivity measurements.The ligand behaves as monodentate O-bonded. All the compounds are high spin and non-conductors except of the perchlorato derivatives, and have different stereochemistries.     

Manganese(II), cobalt(II), nickel(II), copper(II) and zinc(II) complexes with 4-oxo-4H-1-benzopyran-3-carboxaldehyde

The complexes Mn(II), Co(II), Ni(II) and Zn(II) with 4-oxo-4H-1-benzopyran-3-carboxaldehyde were synthesized and characterized by elemental analysis, infrared and UV spectroscopy, X-ray diffraction patterns, magnetic susceptibility, thermal gravimetric analysis, conductivity and also solubility measurements in water, methanol and DMF solution at 298 K. They are polycrystalline compounds with various formula and different ratio of metal ion:ligand. Their formula are following: [MnL₂(H₂O)](NO₃)₂·2H₂O, [CoL₂](NO₃)₂·3H₂O, [NiL₂](NO₃)₂·3H₂O, [CuL₂](NO₃)₂·H₂O and [ZnL₃](NO₃)₂, where L = C₁₀H₆O₃. The coordination of metal ions is through oxygen atoms present in 4-position of γ-pyrone ring and of aldehyde group of ligand. Chelates of Mn(II), Co(II), Ni(II) and Cu(II) obey Curie–Weiss law and they are high-spin complexes with the weak ligand fields. The thermal stability of analyzed complexes was studied in air at 293–1,173 K. On the basis of the thermoanalytical curves, it appears that thermal stability of anhydrous analysed chelates changed following: Cu (423 K) < Zn (438 K) ~ Co (440 K) < Ni (468 K). The gaseous products of thermal decomposition of those compounds in air atmosphere are following: CO₂, CO, NO₂, N₂O, hydrocarbons and in case of hydrates also water. The molar conductance data confirm that the all studied complexes are 1:2 electrolytes in DMF solution.     

Structural elucidation of manganese(II), iron(III), cobalt(II), nickel(II), copper(II) and zinc(II) complexes of a new multidentate dihydrazino quinoxaline derivative

Summary Manganese(II), iron(III), cobalt(II), nickel(II), copper(II) and zinc(II) complexes of a new multidentate oxygen-nitrogen donor, bis(N-salicylidene)-2,3-dihydrazino-1,4-quinoxaline (H₂BSDHQ) were prepared and characterised by elemental analysis, conductance, thermal, spectral and magnetic data. H₂BSDHQ deprotonates to give a dibasic ONNO donor set in a trivalent iron(III) complex, which binds to the divalent metal ions in a bis-tridentate fashion, using two monobasic ONN donor sets, and resulting in polymeric complexes. Octahedral geometries are proposed for all these complexes, and preliminary studies show that they possess potential antimicrobial activity.     

Complexes of chromium(III), manganese(II) and nickel(II) with methylhydrazinecarboxylate and 1,1-dimethylhydrazinecarboxylate ligands

Summary New complexes of chromium(III), manganese(II) and nickel(II) with methylhydrazinecarboxylate (MeCz) and of manganese(II) and nickel(II) with 1,1-dimethylhydra-zinecarboxylate (Me₂Cz) were prepared by reacting salts of the metals with CO₂-saturated solutions of the hydrazines in EtOH. The compounds [Cr(MeCz)₃]·2H₂O, Ni(MeCz)₂(H₂O)₃·MMH, Mn(MeCz)₂(H₂O)₂(MMH = monomethylhydrazine) and M(Me₂Cz)₂(H₂O)₂ (M = Mn or Ni) were investigated using d.t.a., t.g.a., electronic and i.r. spectroscopy and by magnetic susceptibility measurements.     

Complexes of 2-amino-5(o-hydroxyphenyl)-1,3,4-thiadiazole with copper(II), nickel(II), cobalt(II), zinc(II) and iron(II)

Summary 2-Amino-5(o-hydroxyphenyl)-1,3,4-thiadiazole (AHPT) complexes of the type M(AHPT-H), (M = Cu^ll, Ni^lI, Co^lI, Zn^ll and Fell) have been prepared and characterized by analytical, magnetic, spectral (electronic and i.r.), powder x-ray diffraction and t.g. techniques. Magnetic and electronic data indicate that the Fe^II, Co^II, Cu^II complexes are octahedral and that the Ni^lI complex is a mixture of square planar and octahedral geometries.     

Complexation of copper(II), nickel(II), cobalt(II), zinc(II), and manganese(II) chlorides with acylated polyethylenepolyamines

Complexation of some non-ferrous metals with acylated polyethylenepolyamines in 90% aqueous ethanol has been studied by pH-metric titration and visible absorption spectroscopy. The composition and stability constants of complexes have been determined.     

Chromium(III), manganese(II), iron(III), cobalt(II), nickel(II) and copper(II) complexes with a pentadentate, 15-membered new macrocyclic ligand

Complexes of Cr^III, Mn^II, Fe^III, Co^II, Ni^II and Cu^II containing a macrocyclic pentadentate nitrogen–sulphur donor ligand have been prepared via reaction of a pentadentate ligand (N₃S₂) with transition metal ions. The N₃S₂ ligand was prepared by [1 + 1] condensation of 2,6-diacetylpyridine with 1,2-di(o-aminophenylthio(ethane. The structures of the complexes have been elucidated by elemental analyses, molar conductance, magnetic susceptibility measurements, i.r., electronic and e.p.r. spectral studies. The complexes are of the high spin type and are six-coordinate.     

Complexes of 2-acetylpyridinesemicarbazone and 2-acetylpyridinethiosemicarbazone with cobalt(II), chromium(III) and copper(II)

Summary The synthesis and characterization of 2-acetylpyridine-semicarbazone (apsc) and 2-acetylpyridinethiosemicarbazone (aptsc) and their complexes with CoCl₂, CrCl₃ and CuCl₂ are reported. These compounds were characterized on the basis of elemental analyses, electronic and i.r. spectra, magnetic moments and conductivity measurements. The molar conductivities in dimethyl formamide indicate the non-ionic nature of the metal chelates. An octahedral structure is proposed for the chromium(III) chelate-complexes, tetrahedral for the copper(II) compounds and tetrahedral or octahedral for the cobalt(II). Apsc and aptsc are bidentate but with different donors, though aptsc is monodentate in its complex with CrCl₃.     

Complexes of cobalt(II), nickel(II) and copper(II) with 4-amino-3,5-dimethylisoxazole

Summary Complexes of the type M(4-ADI)_nX₂ · mH₂O (where 4-ADI = 4-amino-3,5-dimethylisoxazole; n = 1–4; X = Cl, Br, I, SCN, ClO₄; m = 1–4) have been studied by i.r. and electronic spectroscopy, magnetic and conductivity measurements. The ligand behaves as a monodentate -NH₂ bonded species in monomeric complexes, but as a bridging ligand-NH₂ and -N(ring) bonded species in polymeric complexes. All the compounds have an octahedral stereochemistry, except Co(4-ADI)₂X₂ (X = Cl, Br, I) complexes, which are tetrahedral.     

Synthesis and spectral properties of new complexes between glycine and titanium(III), vanadium(III), chromium(III), iron(III), cobalt(II), nickel(II) and copper(II)

Summary Complexes of formula [MCl₃(glyH)₃] (M=Ti, V and Fe) [CrCl₃(glyH)₂H₂O], [MCl₂(glyH)₂(H₂O)₂] (M=Co and Cu) and [NiCl₂(glyH)₃H₂O] have been prepared and characterized by potentiometric curves, chemical analysis, magnetic properties, i.r. and electronic spectral data.     

Synthesis,magnetic and spectral studies of iron(III), cobalt(II,III), nickel(II), copper(II) and zinc(II) complexes of 4–formylantipyrine N(4)-antipyrinylthiosemicarbazone

4–Formylantipyrine N(4)-antipyrinylthiosemicarbazone and its metal complexes have been synthesized and characterized. Elemental analyses, molar conductivities, magnetic measurements and spectral (i.r., electronic, n.m.r., e.s.r.) studies have been used to characterize the complexes. The i.r. spectra show that the thiosemicarbazones behave as bidentate (NS) or tridentate ligands (ONS), either in the thione or thiolato form. Stereochemistries are proposed for the complexes on the basis of both spectral and magnetic studies.     

Complexes of cyclocarbohydroxamic acids with cobalt(II), nickel(II) and copper(II)

A spectroscopic investigation of the reactions of cyclopropanecarbohydroxamic acid (CPAH) with CoII and of cyclohexylacetohydroxamic acid (CHAH) with CoII, NiII and CuII in aqueous solution reveals the sole formation 1:2 complexes at equilibrium. Stability constants (log2 at 25°C and I=0.1 mol dm–3) are 9.11, 9.91, 11.70 and 24.18 for [Co(CPA)2], [Co(CHA)2], [Ni(CHA)2] and [Cu(CHA)2], respectively. Spectral and magnetic studies of the isolated complexes indicate octahedral coordination via the oxygen atoms of the hydroxamate group for the CoII and NiII complexes but a square planar geometry for the CuII complex.     

Complexes of chromium(III), cobalt(II) and copper(II) with sulphur or oxygen and nitrogen donors

Summary The synthesis and characterization of 4-acetyl-pyridinesemicarbazone (4-apsc) and 4-acetylpyridine-thiosemicarbazone (4-aptsc) and their complexes with CrCl₃, CoCl₂ and CuCl₂ are reported. These compounds were characterized on the basis of elemental analyses, electronic and i.r. spectra, magnetic moments and conductivities measurements. The compounds are nonconductors in dimethylformamide. Tentative structures for the complexes are suggested.     

Synthesis,characterization and susceptibility of bacteria against Sulfamethoxydiazine complexes of copper(II), zinc(II), nickel(II), cadmium(II), chromium(III) and iron(III)

Complexes of sulfamethoxydiazine with Cu(II), Zn(II), Ni(II), Cd(II), Cr(III) and Fe(III) have been synthesized and characterized on the basis of conductivity measurements, elemental analyses, UV, IR, ¹H?NMR and thermal studies. It is shown that sulfamethoxydiazine behaves as a bidentate ligand, binding the metal ion through the sulfonyl oxygen and sulfonamide nitrogen. In vitro susceptibility tests of these complexes against Escherichia coli, Bacillus subtilis, Proteus vulgaris and Staphylococcus aureus were carried out. The results show that the antibacterial activities of the complexes of Zn(II), Cu(II), Cr(III) and Fe(III) are, in general, stronger than that of sulfamethoxydiazine, while the complexes of Cd(II) and Ni(II) are less active.     

Thermoanalytical investigations of 4-methylpiperazine-1-carbodithioic acid ligand and its iron(III), cobalt(II), copper(II) and zinc(II) complexes

The thermal decomposition studies on 4-methylpiperazine-1-carbodithioic acid ligand (4-MPipzcdtH) and its complexes, viz. [M(4-MPipzcdtH)_n](ClO4)_n (M=Fe(III) when n=3; M=Co(II), Cu(II) when n=2) and [Zn(4-MPipzcdtH)₂]Cl₂ have been carried out using non-isothermal techniques (TG and DTA). Initial decomposition temperatures (IDT), indicate that thermal stability is influenced by the change of central metal ion. Free acid ligand exhibits single stage decomposition with a sharp DTA endotherm. Complexes, [M(4-MPipzcdtH)_n](ClO₄)_n undergo single stage decomposition with detonation and give rise to very sharp exothermic DTA curves while the complex [Zn(4-MPipzcdtH)₂]Cl₂ shows three-stage decomposition patterns. The kinetic and thermodynamic parameters, viz. the energy of activation E, the frequency factor A, entropy of activation S and specific rate constant k, etc. have been evaluated from TG data using Coats and Redfern equation. Based upon the results of the differential thermal analysis study, the [M(4-MPipzcdtH)_n](ClO₄)_n complexes have been found to possess characteristic of high energy materials.     

Solution state and complexing ability of 1,4-bis(amidomethylsulfinyl)butane toward iron(III), copper(II), cobalt(II), nickel(II), and manganese(II)

The solution state and thermodynamic stability of complexes of the new antituberculosis agent 1,4-bis(amidomethylsulfinyl)butane (L) with iron(III), copper(II), cobalt(II), nickel(II), and manganese(II) in an aqueous solution in the presence and in the absence of the nonionic surfactant Brij 35 were studied by spectrophotometry, pH potentiometry, NMR relaxation technique (T = 25 °C; variable ionic strength), and mathematical simulation. The geometry optimization of all structures was carried out by the molecular mechanics method MM2 in order to obtain data on coordination modes. In addition, the structure of 1,4-bis(amidomethylsulfinyl)butane was refined by the DFT/B3LYP/6-311++G(d,p) quantum chemical method using the IEFPCM model to take into account solvent effects. In an aqueous solution (in the concentration range of 1.3?10^–5—1?10^–3 mol L–1) and in the presence of Brij 35, 1,4-bis(amidomethylsulfinyl)butane exists as a neutral monomer. The Beer—Lambert—Bouguer law is obeyed in a wide concentration range for compound L in an aqueous solution, as well as in the presence of the surfactant, which can be used for the quantification of compound L. Iron(III), cobalt(II), and nickel(II) were shown to form 1: 1 mononuclear complexes with L; and copper(II) forms, 1: 1 and 2: 2 complexes. The presence of Brij 35 in the Cu²⁺—L system at a micellar concentration promotes the formation of a dinuclear complex.