Some tetrazolium salts and their ion-association complexes with the molybdenum(VI) — 4-nitrocatechol anionic chelate

Several commercially available 2H-tetrazolium salts (TS) {2,3,5-triphenyl-2H-tetrazolium chloride (TTC), 3-(1-naphthyl)-2,5-diphenyl- 2H-tetrazolium chloride (Tetrazolium Violet, TV), 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT), 2-(4-iodophenyl)-3-(4-nitrophenyl)-5-phenyl-2H-tetrazolium chloride (INT) and 3,3′-(3,3′-dimethoxy-4,4′-biphenylene)-bis(2,5-diphenyl- 2H-tetrazolium) chloride (Tetrazolium Blue Chloride, BTC)} and their ion-associated complexes (IAC) with the Mo(VI) — 4-nitrochatechol (4-NC) anionic chelate [MoO₂(4-NC)₂]²⁻ have been investigated by differential thermal analysis (DTA) and thermogravimetric analysis (TG). Some special features of the thermal behavior of the compounds have been discussed. The results show that the thermal stability of IAC depends on the factors determining the values of their association constants β: molecular mass and the presence of nitrophenyl substituent(s) in the tetrazolium ring.     

Electron transfer: 150. The reaction of corrin-bound cobalt(III) with indium(I) — an additional mechanistic variation

(Corrin)cobalt(III) is reduced by indium(I) to its Co(II) counterpart (cob(II)alamin, B_12r) at pH 1-2 in aqueous chloride. In these solutions the aqua oxidant (B_12a) is in mobile anation equilibrium with its chloro derivative. At [Cl^–] 0.03 M, consumption of Co(III) is exponential and proceeds by parallel paths involving the aqua- and chloro-substituted oxidants. At [Cl^–] 0.10 M, rates are governed mainly by an preliminary act requiring In(I) and 2 Cl^–, but no Co(III). This initiation step generates a more reactive In(I) species which is taken to result from a slow heterolysis and loss of ligating water from InCl₂ ^–(aq).     

High-spin complexes of iron(III) with ethylene glycol and 3(2′-hydroxyphenyl)-5-(4′-substituted phenyl) pyrazolines

Complexes of iron(III) with ethylene glycol and 3(2′-hydroxyphenyl)-5-(4′-substituted phenyl) pyrazolines, [Fe(OCH₂CH₂O)(C₁₅H₁₂N₂OX)] _m ? nH₂O and [Fe(C₁₅H₁₂N₂OX)₂(OCH₂CH₂OH)] (where OCH₂CH₂O and OCH₂CH₂OH = ethylene glycol moiety; C₁₅H₁₂N₂OX = 3(2′-hydroxyphenyl)-5-(4-X-phenyl)pyrazoline; X = H, CH₃, OCH₃, or Cl; m = 2–3 and n = 2–3) have been synthesized and characterized by elemental analysis (C, H, N, Cl, and Fe), molecular weight measurement, magnetic moment data, thermogravimetric analysis, molar conductance, spectral (UV-Vis, IR, and FAB mass), scanning electron microscopy, and X-ray diffraction studies. Bonding of ethylene glycol and pyrazolines in these complexes and the particle size of iron(III) complexes are discussed. Antibacterial and antifungal potential of free pyrazoline and some iron(III) complexes are also discussed.     

Supramolecular inclusion complexes of β-cyclodextrin with 4-(acyloxy)-4-(cyclopropylethynyl)-1-(2-ethoxyethyl)piperidines

4-Acyloxy-4-(cyclopropylethynyl)-1-(2-ethoxyethyl)piperidines have been synthesized by reaction of 1-(2-ethoxyethyl)piperidin-4-one with cyclopropylacetylene and subsequent acylation of intermediate 4-(cyclopropylethynyl)piperidin-4-ol. The resulting esters react with β-cyclodextrin to give supramolecular inclusion complexes. The complexation is accompanied by inclusion of the N-ethoxyethyl fragment of one substrate molecule in the inner cavity of one receptor molecule. The structure of 4-acyloxy-4-(cyclopropylethynyl-1-(2-ethoxyethyl)piperidines and their inclusion complexes with cyclodextrin has been studied by NMR spectroscopy.     

New rhenium(III) complexes with fluorinated β-diketones

Five new rhenium(III) complexes of the general formula ReCl₂(R_FCOCHCOR_F)(PPh₃)(OPPh₃), where R_F = CF₃ (I), C₂F₅ (II), C₃F₇ (III), C₄F₉ (IV), and CF₃CFOC₃F₇ (V), were synthesized. The known rhenium(V) complex ReOCl₂(OC₂H₅)(PPh₃)₂, which can readily be obtained from metallic rhenium, was used as a precursor. Two polymorphous modifications of compound I were found and studied by X-ray diffraction analysis. The thermal properties of the synthesized complexes were characterized by the DTA-TG method.     

Extraction chromatographic study of aluminium(III) and mutual separation of aluminium(III), gallium(III), indium(III) and thallium(III) with N-n-octylaniline

A selective method has been developed for extraction chromatographic studies of aluminium(III) and its separation from several metal ions with a chromatographic column containing N-n-octylaniline (liquid anion exchanger) coated on silanized silica gel as a stationary phase. The aluminium(III) was quantitatively extracted with the 0.065 mol/L N-n-octylaninine from 0.013 to 0.05 mol/L sodium succinate at a flow rate of 1.0 mL/min. The extracted metal ion has been recovered by eluting with 25.0 mL of 0.05 mol/L hydrochloric acid and estimated spectrophotometrically with aurintricarboxylic acid. The effects of the acid concentration, the reagent concentration, the flow rate and the eluting agents have been investigated. The log-log plots of distribution coefficient (KdAl(III)) versus N-n-octylaniline concentrationin 0.005 and 0.007 mol/L sodium succinate gave theslopes 0.5 and 0.7 respectively and showed theprobable composition of theextracted species was 1:1 (metal to amine ratio) and the nature of extracted species is [RR''NH2+ Al succinate2-] org. .The extraction of aluminium(III) was carried out in the presence of various ions to ascertain the tolerance limit of individual ions. Aluminium(III) has been separated from multicomponent mixtures, pharmaceutical samples and synthetic mixtures corresponding to alloys. A scheme for mutual separation of aluminium(III), indium(III), gallium(III) and thallium(III) has been developed by using suitable masking agents. The method is fast, accurate and precise.     

The infrared spectra of complexes with planar dithiooxamides—III. The Ni(II) polymeric complexes

Thermal analysis, u.v. spectra and i.r. spectra are given for some nickel complexes and their isotopes of planar dithiooxamides, the results are explained by assuming planar and octahedral S,N conformations about the nickel atoms in a polymeric structure.     

Thermal analysis of rare-earth metal(III) hexa(isothiocyanato)chromate(III) complexes with ɛ-caprolactam

Thermal decomposition of the complexes [LnL₈][Cr(NCS)₆] (Ln = La³⁺, Ce³⁺, Pr³⁺, Nd³⁺, Sm³⁺, Eu³⁺, Gd³⁺, Tb³⁺, Dy³⁺, Ho³⁺, Er³⁺, Tm³⁺, Yb³⁺, Lu³⁺; L = ɛ-C₆H₁₁NO) in air and in inert atmosphere was studied by thermogravimetry, X-ray phase analysis, IR spectroscopy, and mass spectrometry. The compositions of gaseous and solid thermolysis products were established. A reversible thermochromic effect was found on heating to 200–210°C.     

Lanthanide complexes with bis(2′-quinolyl)-2,6-pyridine

Complexes of lanthanide (III) nitrates, thiocyanates and perchlorates with the tridendate ligand, bis(2′-quinolyl)-2,6-pyridine are reported. The molar conductivity values in acetonitrile-benzene mixture (80−20) and IR data indicate that the nitrate and thiocyanate complexes are non electrolytes and the perchlorate 1:3 electrolytes. The electronic spectra of the Pr, Nd, Ho, and Er complexes show enhancement of intensities for the hypersensitive bands; moreover, except in the case of the Er^III complexes, where a very slight red shift is observed, other complexes show the expected nephelauxetic effect.     

Ligand field analysis of tris(aminoacidato)cobalt(III) complexes with glycinato(N,O) and β-alaninato(N,O) metal chelate rings

In addition to showing a well-known demarcation between facial and meridional configurations the ligand field spectra of Co(βAla)_x(Gly)_3-x (x = 1 or 2) [βAla = β-alan- inato(N,O) ring, and gly = glycinato(N,O) ring] complexes provide a rare example of a marked difference in the observed splitting pattern of the¹T_1g(O_h) level among the three possible meridional isomers generated by cyclic permutation of chelate rings with respect to the pseudo three-fold axis. Angular overlap calculations which consider an anisotropy of the metal-car☐ylate oxygen donor interaction reproduce fairly well the ligand field spectra of the complete series of Co(βAla)_x(Gly)_3-x (x = 0, 1, 2 or 3) complexes.     

Bis(diphenylphosphino)methylamine as chelate ligand in pentamethylcyclopentadienylrhodium(III) and iridium(III) complexes.: Crystal structure of [(η5-C5Me5)RhCl{η2-P,P′-(PPh2)2NMe}]BF4

Reactions of the dimers [{(η⁵-C₅Me₅)MCl(μ-Cl)}₂] (M=Rh, Ir) with the ligand NMe(PPh₂)₂ in 1:2 molar ratio afford the mononuclear cationic complexes [(η⁵-C₅Me₅)MCl{η²-P,P′-(Ph₂P)₂NMe}]Cl (M=Rh 1, Ir 2). Similar iodide complexes, [(η⁵-C₅Me₅)MCl{η²-P,P′-(Ph₂P)₂NMe}]I (M=Rh 3, Ir 4), can be prepared by N-functionalization of co-ordinated dppa ligand in complexes [(η⁵-C₅Me₅)MCl{η²-P,P′-(Ph₂P)₂NH}]BF₄. The tetrafluoroborate derivatives, [(η⁵-C₅Me₅)MCl{η²-P,P′-(Ph₂P)₂NMe}]BF₄ (M=Rh 5, Ir 6) are prepared by reaction of complexes 1–4 with AgBF₄ in acetone. All the compounds described are characterised by microanalysis, IR and NMR (¹H, ³¹P{¹H}) spectroscopy. The crystal structure of complex 5 is determined by X-ray diffraction methods. The complex exhibits a pseudo-octahedral molecular structure with a C₅Me₅ group occupying three co-ordination positions and a bidentate chelate P,P′-bonded ligand and a chloride atom completing the co-ordination sphere.     

Copper(II) and lanthanoid(III) complexes of a new β-diketonate ligand with an appended non-coordinating phenol group

New mononuclear compounds of the ligand 1-(2-hydroxyphenyl)-3-phenylpropane-1,3-dione (H₂L) with Cu(II) and several lanthanoid(III) ions, where Ln(III) = Pr, Nd, Eu, Gd, have been synthesized and characterized by spectroscopic methods and X-ray crystal structure determinations. In all compounds, the ligand coordinates in a bidentate chelating manner, using the diketone function. In the [Cu(HL)₂], the coordination geometry of Cu(II) ion is slightly distorted square-planar; two strong intramolecular (OH?O) hydrogen-bonding interactions are established between the phenolate group and the neighboring ketone function. The lanthanoid(III) compounds have the general formula [Ln(HL)₃(CH₃OH)₂] · CH₃OH · 2H₂O; the lanthanoid(III) ion (Ln) is eight-coordinated and the coordination geometry is based on a distorted square-antiprism. In addition to the intramolecular hydrogen bonding (OH?O), intermolecular hydrogen-bonding interactions are also present between the coordinated methanol molecule and the non-coordinated methanol molecule giving rise to a three-dimensional network.     

Synthesis and X-ray structural characterization of dioxomolybdenum(VI) complexes with N′-(5-chloro-2-hydroxybenzylidene)-4-methylbenzohydrazide and N′-(2-hydroxybenzylidene)-4-methylbenzohydrazide

Two new dioxomolybdenum(VI) complexes, [MoO₂(ClHm)(CH₃OH)] (I) and [MoO₂(Hm)(CH₃OH)] (II) with the hydrazone ligands H₂ClHm and H₂Hm derived from 4-methylbenzohy-drazide with 5-chlorosalicylaldehyde and salicylaldehyde, respectively, have been synthesized and structurally characterized by physicochemical methods and single-crystal X-ray determination. The crystal of I crystallizes in the triclinic space group \(P\bar 1\), with a = 7.839(2), b = 9.656(3), c = 11.548(4) Å α = 88.885(3)°, β = 87.454(3)°, γ = 88.996(3)°, V = 873.0(5) ų, Z = 2, R ₁ = 0.0292, wR ₂ = 0.0685, S = 1.092. The crystal of II crystallizes in the triclinic space group \(P\bar 1\), with a = 7.780(2), b = 10.584(3), c = 10.628(3) Å, α = 91.462(3)°, β = 104.818(3)°, γ = 103.288(3)°, V = 820.1(4) ų, Z = 2, R ₁ = 0.0403, wR ₂ = 0.0784, S = 1.065. An X-ray analysis indicates that the structures of both complexes are similar to each other. The molybdenum atom in each complex is in an octahedral coordination environment constructed by two oxo groups, an NO₂ donor set of the hydrazone ligand, and one methanol O atom.     

Investigation of supramolecular inclusion complexes with β-cyclodextrin of 1-(2-ethoxyethyl)-4-(pentyn-1-yl)-4-hydroxypiperidine and 1-(2-ethoxyethyl)-4-(pentyn-1-yl)-4-benzoyloxypiperidine oxalate by NMR spectroscopy

A comparative analysis of ¹H and ¹³C NMR spectra of 1-(2-ethoxyethyl)-4-(pentyn-1-yl)-4-hydroxypiperidine, 1-(2-ethoxyethyl)-4-(pentyn-1-yl)-4-benzoyloxypiperidine oxalate and their inclusion complexes with β-cyclodextrin was performed. The differences in values of chemical shifts of ¹H and ¹³C nuclei of the substrates and the receptor in the inclusion complexes were determined. It was found that the formation of complexes of 1-(2-ethoxyethyl)-4-(pentyn-1-yl)-4-hydroxypiperidine and 1-(2-ethoxyethyl)-4-(pentyn-1-yl)-4-benzoyloxypiperidine oxalate with β-cyclodextrin was accompanied by insertion of one N-ethoxyethyl fragment of the substrate molecule into the inner sphere of one molecule of the receptor.     

Synthesis and crystal structure of lanthanum(III) Iodomercurate(II) complexes with ɛ-Caprolactam

The X-ray diffraction study of the crystalline products of the reaction between potassium tetraiodomercurate(II), ?-caprolactam, and lanthanum(III) nitrate at a ratio of 3: 16: 2 in an aqueous solution has shown the presence of the following three new crystalline compounds: [LaCpl₈]₂[HgI₄]₃ (I), [LaCpl₈][HgI₄]I₃ (II), and [LaCpl₇(H₂O)]₂[HgI₄]₂[Hg₂I₆] (III), where Cpl is ?-caprolactam ?-C₆H₁₁NO. Compounds I and II crystallize in tetragonal crystal system, space groups P4₂/n and $I\bar 4$ , respectively. For compound I, a = 18.59320(10) Å, c = 19.5782(3) Å, V = 6738.32(12) ų, Z = 2, and ρ_calc = 2.067 g/cm³. For compound II, a = 13.2245(10) Å, c = 20.0310(3) Å, V = 3503.17(6) ų, Z = 2, ρ_calc = 2.022 g/cm³. The crystals of compound III are monoclinic (space group P _{2 1}/n, a = 20.1202(6) Å, b = 14.0569(4) Å, c = 46.3228(12) Å, β = 93.4770(10)°, V = 13077.3(6) ų, Z = 4, ρ_calc = 2.274 g/cm³). [La(Cpl)₈]₂[Hg₂I₆]₃ (IV), a new double ionic complex salt, has also been synthesized and studied by X-ray diffraction. The crystals of compound IV are triclinic (space group $P\bar 1$ , a = 12.5021(3) Å, b = 14.6436(3) Å, c = 21.4695(4) Å, α = 84.2300(10)°, β = 87.2230(10)°, γ = 74.9970(10)°, V = 3776.30(14) ų, Z = 1, ρ_calc = 2.452 g/cm³). All complexes have a dicrete ionic structure, and the nearest surrounding of a La atom is distorted square-prismatic or trigonal-dodecahedral. The crystal packing of cations is distorted face-centered cubic (I and II) or body-centered cubic (III and IV) with anions located in its cavities.     

Iron(III)5(2′-hydroxyphenyl)-3-(4-X-phenyl)pyrazolinates and their addition complexes with N,P donor ligands: synthesis,spectral and antimicrobial investigations

Iron(III)5(2′-hydroxyphenyl)-3-(4-X-phenyl)pyrazolinates of the type (C₁₅H₁₂N₂OX)₃Fe [where X =–H,–Cl,–CH₃,–OCH₃] have been synthesized by reaction of anhydrous FeCl₃ with the sodium salts of pyrazoline in 1 : 3 molar ratio. Their addition complexes with N and P donor ligands [2,2′-bipyridine, 1,10-phenanthroline and triphenylphosphine] were prepared in 1:1 molar ratio. These newly synthesized derivatives have been characterized using elemental analysis (C, H, N and Fe), molecular weight measurement, magnetic moment data, FAB mass, ³¹P NMR and Mössbauer spectral data. The complexes have been examined for crystalline/amorphous nature through XRD; all complexes are amorphous. Octahedral geometry around iron(III) confirms the presence of three bidentate pyrazoline ligands in iron(III)5(2′-hydroxyphenyl)-3-(4-X-phenyl)pyrazolinates. In addition complexes pyrazoline is monodentate. The bidentate and monodentate behavior of pyrazoline ligands was confirmed by IR spectral data. All the complexes were tested for their in-vitro antimicrobial activity. The metal complexes and their adducts exhibit better antibacterial and antifungal activity than the pyrazolines.