Reactions of germanium(II), tin(II), and antimony(III) chlorides with acenaphthene-1,2-diimines

Reactions of diimines dtb-BIAN and dph-BIAN with GeCl₂ afford germanium(II) complexes with radical-anionic ligands, (dtb-BIAN)GeCl (5) and (dph-BIAN)GeCl (6a), respectively, where dtb-BIAN is 1,2-bis[(2,5-di-tert-butylphenyl)imino]acenaphthene and dph-BIAN is 1,2-bis[(2-biphenyl)imino]acenaphthene. The latter reaction gives 6a along with [(dph-BIAN)GeCl]⁺[GeCl₃]⁻ (6b). The reactions of tin(II) and antimony(III) chlorides with dtb-BIAN and dpp-BIAN produce complexes of these halides with neutral coordinated diimines, viz., (dtb-BIAN)SnCl₂ (7) and (dpp-BIAN)SbCl₃ (8) (dpp-BIAN is 1,2-bis[(2,6-di-isopropylphenyl)imino]acenaphthene). Paramagnetic complexes 5 and 6a were studied by ESR spectroscopy. Diamagnetic compounds 7 and 8 were characterized by ¹H NMR spectroscopy. The structures of complexes 5, 6a,b, 7, 8, and (dpp-BIAN)Ge (9) were established by X-ray diffraction analysis. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 71–80, January, 2006.     

Analytical separation of antimony(III) from bismuth(III), lead(II), gallium(III), thallium(III), tellurium(IV) and tin(IV) with cyanex 302

A method is proposed for the separation of antimony(III) (100–400 g) from bismuth(III), lead(II), gallium(III), thallium(III), tellurium(IV) and tin(IV) from an aqueous solution of pH 0.5–1.5 using 8×10^–3–1×10^–2 mol dm^–3 cyanex 302 dissolved in toluene as an extractant. The antimony is stripped from the cyanex phase with water and determined spectrophotometrically with iodide. Various experimental parameters are optimized and the probable 13 stoichiometry of the extracted species is evaluated. The method is applicable to the analysis of alloys and pharmaceutical samples. The separation and determination take only 20 min.     

Nickel(II), copper(II), cobalt(II), and palladium(II) complexes with a Schiff base: crystal structure,DFT study and copper complex catalyzed aerobic oxidation of alcohol to aldehyde

Ni(II), Cu(II), Co(II), and Pd(II) complexes were synthesized with a Schiff base containing thioether with ONS donors chelating to the metal center. The ligand and complexes were characterized by elemental analysis, FT-IR, ¹H-NMR, UV–visible spectroscopy and magnetic studies. The crystal structures of the ligand and its Ni(II) and Pd(II) complexes were determined by single-crystal X-ray diffraction analysis. Structures revealed that the ligand chelated with Ni(II) and Pd(II) center in slightly distorted octahedral and slightly distorted square planar fashion, respectively. DFT studies of the Pd(II) complex revealed that the calculated structural parameters are very close with the experimentally observed data. The Cu(II) complex shows very good catalytic activity toward the conversion of alcohol to aldehyde under aerobic oxidation with ammonium persulfate.     

Preparation and structural characterization of nickel(II), cobalt(II), zinc(II) and tin(IV) complexes of the isatin Schiff bases of S-methyl and S-benzyldithiocarbazates

The molecular structures of the isatin Schiff bases of S-methyldithiocarbazate (Hisasme) and S-benzyldithiocarbazate (Hisasbz) have been determined by X-ray diffraction and their complexes of general formula [ML₂]·n(solvate) [M = Co²⁺, Ni²⁺, Zn²⁺; L = anionic forms of Hisasme or Hisasbz; solvate = DMF, DMSO; n = 1, 2] and [Sn(L)Ph₂Cl]·nMeOH (n = 0, 1) have been synthesized and characterized by a variety of physicochemical techniques and X-ray diffraction. The bis-ligand complexes, [Ni(isasbz)₂]·2DMSO and [Co(isasme)₂]·DMF have a six-coordinate, distorted octahedral geometry with the two uninegatively charged tridentate ONS ligands coordinated to the metal ions meridionally via the amide O-atoms, the azomethine nitrogen atoms and the thiolate sulfur atoms. By contrast, the crystal structure of [Zn(isasbz)₂]·2DMF shows a four-coordinate distorted tetrahedral geometry with the two Schiff bases coordinated as NS bidentate ligands via the azomethine nitrogen atoms and the thiolate sulfur atoms. Steric constraints of the rigid tridentate ligands lead to unusual ‘pseudo-coordination’ of the O-donors which occupy sites close to the metal but too distant to be considered as true coordinate bonds.The crystal structures of the tin(IV) complexes [SnLPh₂Cl]·nMeOH (L = isasme and isasbz; n = 0, 1) also show that the Schiff bases act as monoanionic bidentate NS chelating agents coordinating the tin(IV) ion via the azomethine nitrogen atoms and the thiolate sulfur atoms, the tin atom in each complex is five-coordinate with a highly distorted geometry intermediate of square pyramidal and trigonal bipyramidal. Again Sn?O contacts are weak and do not qualify as coordinate bonds.     

Synthesis,crystal structure and characterization of 3-thiophene aldehyde thiosemicarbazone and its complexes with cobalt(II), nickel(II) and copper(II)

The reaction of cobalt(II), nickel(II), copper(II) chlorides and bromides with 3-thiophene aldehyde thiosemicarbazone (3TTSCH) leads to the formation of a series of new complexes: [Co(3TTSC)₂], [Ni(3TTSC)₂], [CuCl(3TTSC)]₂, [CuBr(3TTSC)]₂ and [CuBr₂(3TTSCH)]. The crystal structures of the free ligand and of the compound [Ni(3TTSC)₂] have been determined by X-ray diffraction methods. For all these complexes, the central ion is coordinated through the sulfur and the azomethine nitrogen atom of the thiosemicarbazone. [Co(3TTSC)₂], [Ni(3TTSC)₂] and [CuBr₂(3TTSCH)] are mononuclear species, while [CuCl(3TTSC)]₂ and [CuBr(3TTSC)]₂ are binuclear complexes.     

Cytotoxic activity of iron(III), cobalt(III), nickel(II), zinc(II), and cadmium(II) complexes of 2-acetylpyrazine thiosemicarbazone: crystal structure of the cobalt(III) complex

Transition metal complexes [Fe(HL)₂]Cl₃ ? 1.5H₂O (1), [Co(L)₂] ? ClO₄ ? H₂O (2), Ni(HL)₂(ClO₄)₂ ? 2H₂O (3), Zn(HL)L ? BF₄ ? 2H₂O (4), and Cd(HL)₂(ClO₄)₂ ? 2H₂O (5), where HL = C₇H₉N₅S, 2-acetylpyrazine thiosemicarbazone, have been synthesized. Complex 2 was characterized by elemental analysis, infrared spectra, mass spectra, and single-crystal X-ray diffraction. Preliminary in vitro screening showed that 1, 4, and 5 exhibit higher antitumor activity than 2 and 3 against K562 leucocythemia cancer cell line.     

Synthesis and spectroscopic characterization of arsenic(III), antimony(III), bismuth(III), tin(II) and lead(II) dithiocarbamate adducts

The complexes of arsenic(III), antimony(III), bismuth(III), tin(II) and lead(II) with monomethylsubstituted piperidinodithiocarbamates of general formula M(Rdtc)₃ and M(Rdtc)₂ have been prepared and characterized by spectroscopic methods. The results of the spectroscopic studies indicate that the dithiocarbamate ligands are always bidentate, in both the 1:3 and the 1:2 complexes. All the complexes are nonconducting in DMF solution. The thermal behaviour of the complexes has been investigated by TG and DTG techniques. The molecular weight determinations indicate that the trisdithiocarbamates of arsenic and antimony are monomeric, while the bismuth trisderivatives tend to dimerize: polymeric structures can be suggested for the tin(II) and lead(II) compounds.     

Iron(III), cobalt(II,III), copper(II) and zinc(II) complexes of 2-pyridineformamide 3-piperidylthiosemicarbazone

Reduction of 2-cyanopyridine by sodium in the presence of 3-piperidylthiosemicarbazide produces 2-pyridineformamide 3-piperidylthiosemicarbazone, HAmpip. Complexes with iron(III), cobalt(II,III) copper(II) and zinc(II) have been prepared and characterized by molar conductivities, magnetic susceptibilities and spectroscopic techniques. In addition, the crystal structures of HAmpip, [Fe(Ampip)₂]ClO₄, [Cu(HAmpip)Cl₂]·CH₃OH and [Zn(HAmpip)Br₂]·C₂H₆SO have been determined. Coordination is via the pyridyl nitrogen, imine nitrogen and thiolato or thione sulfur when coordinating as the anionic or neutral ligand, respectively.     

Synthesis,characterization, and crystal structures of cobalt(II), copper(II), and zinc(II) complexes of a bidentate iminophenol

A bidentate iminophenol (HL = 2-((4-methoxyphenylimino)methyl)-4,6-di-tert-butylphenol derived from condensation of 4-methoxyaniline and 3,5-di-tert-butyl-2-hydroxybenzaldehyde) was mixed with divalent metal salts to form the corresponding mononuclear metal complexes [M^II(L)₂] (M = Co (1), Cu (2), and Zn (3)). The complexes are characterized by different spectroscopic and analytical tools. X-ray crystal structures of the complexes revealed homoleptic mononuclear complexes with MN₂O₂ coordination. The cobalt(II) (1) and zinc(II) (3) complexes display a pseudo-tetrahedral coordination geometry, whereas the copper(II) complex (2) exhibits a distorted square-planar coordination. The zinc(II) complex (3) emits at 460 nm with a twofold enhancement of emission with respect to the free iminophenol.     

Synthesis and characterization of β-diketiminato complexes of antimony (III) halides

Treatment of SbX₃ (X = Br, Cl) with DippnacnacLi (Dippnacnac = [{N(C₆H₃ⁱPr₂2,6)C(Me)}₂CH]⁻) or Mesnacnac (Mesnacnac = [{N(Mes)C(Me)}₂CH]⁻, Mes = 2,4,6, trimethyl benzene) affords different products that are dependent on the stoichiometry of the reaction and the halide precursor. When DippnacnacLi is reacted with SbBr₃, C-H activation of the ligand backbone is observed and an asymmetric, bridged bromide dimer is isolated. In comparison, the reaction of SbCl₃ with MesnacnacLi affords monomeric MesnacnacSbCl₂. The solid-state structures were determined using X-ray crystallography.     

Synthesis,crystal structure,redox behavior and DNA-binding properties of a series of copper(II) complexes with two new carboxamide derivatives

Four mononuclear copper(II) complexes of two new carboxamide derivatives formulated as [Cu(L¹)₂](ClO₄)₂ (1a), [Cu(L¹)₂](NO₃)₂ (1b), [Cu(L²)₂(H₂O)₂](ClO₄)₂ (2a), and [Cu(L²)₂(H₂O)](NO₃)₂ (2b) have been isolated in pure form from the reaction of L¹ and L² [where L¹ = N-(furan-2-ylmethyl)-2-pyridinecarboxamide and L² = N-(thiophen-2-ylmethyl)-2-pyridinecarboxamide] with copper(II) salts of perchlorate and nitrate. All the complexes were characterized by physicochemical and spectroscopic tools along with single-crystal X-ray diffraction studies. The structural analyses showed that 1 is monomeric of square planar geometry with copper(II) chelated by two L¹ ligands. Complex 2 differs in coordination geometry, being octahedral and distorted square pyramidal. Two L² ligands occupy the equatorial positions of the octahedral 2a and the basal sites of the pyramidal 2b, with water molecules that complete the coordination sphere in each case. Electrochemical studies using cyclic voltammetry showed a reversible redox behavior of the copper(II) in 1 and 2. The electronic spectroscopic behavior and the trend of one electron equivalent redox potential corresponding to a Cu^II/Cu^I couple have also been confirmed by density functional theory calculations. The spectroscopic and viscosity measurement study in tris–HCl buffer suggested an intercalative interaction of 1a and 2 with calf thymus DNA likely due to the stacking between the non-coordinated furan and thiophene chromophore with the base pairs of DNA.     

Crystal structure and luminescence of antimony(III) bromide with aniline

The atomic structure of antimony(III) bromide crystals with anilinium was determined by X-ray diffraction analysis of (C₆H₅NH₃)₂SbBr₅ (a = 19.704(3) Å, b = 7.914(1) Å, c = 25.556(4) Å; space group Pbca, Z = 8, ρ_calc = 2.365 g/cm³). The crystal structure consists of infinite chains of [SbBr₅]^2? complex anions formed by sharing six vertices and the anilinium (C₆H₅NH₃)⁺ cations, through which the chains are linked in layers by N-H...Br hydrogen bonds. The geometrical aspects that determine the luminescent spectral properties of the complex are discussed.     

Synthesis of a novel copper(II) complex and its crystal structure

One novel chiral copper(II) complex was successfully synthesized from the reaction of chiral 1,3-thiazolidine-2-thione ligand with CuCl₂ in dichloromethane in the presence of Et₃N and DMAP at room temperature. Its unique crystal structure was unambiguously disclosed by X-ray analysis. The crystal is tetragonal, space group I4(1), space group a=15.0875(11), b=15.0875(11), c=19.362(3) Å, =90, β=90, γ=90°, V=4407.4(8) ų, Z=8, ρ_calc=1.639 mg cm⁻³.     

Synthesis,structure, and DNA binding of three reduced amino-acid Schiff-base zinc(II), nickel(II), and cadmium(II) complexes

Three new reduced amino-acid Schiff-base complexes, [Zn(HL)₂] · H₂O (1), [Ni(HL)₂] · H₂O (2), and [Cd(HL)₂] · H₂O (3), where H₂L is a reduced Schiff base derived from condensation of N-(2-hydroxybenzaldehyde) and L-histidine, have been synthesized and characterized by elemental analysis, UV-Vis absorption spectra and single crystal X-ray diffraction. Complexes 1–3 are isostructural. All metal centers are six-coordinate with O₂N₄ donor sets in slightly distorted octahedra. Unlike its Schiff-base counterpart, the deprotonated monoanionic ligand HL^? has a more flexible backbone and two HL^? are tridentate to one metal. Moreover, the binding interactions of these complexes with calf thymus DNA (CT-DNA) have been investigated by UV-Vis spectra and fluorescence quenching, which show that the complexes bind in an intercalative mode.     

Synthesis and properties of the chain-like polymeric copper (II) complexes bridged by bis(diphenylphosphino oxide)ethane

At room temperature, the chain-like polymeric copper (II) complexes bridged by bis (diphenylphosphino oxide) ethane (dppeO2), [Cu(dppeO2)X2]n[X=Cl(1), Br(2)] have been prepared and characterized by elemental analysis, 31P NMR, TG-DTA and X-ray analysis for [ CuBr2 (dppeO2) ] n The chain is composed of subunits containing tetrahedron coordinated copper (II) atoms. The four-coordinated copper (II) atom is ligated to another four-coordinated copper (II) atom through dppeO2. The coordination sphere of copper(II) atom is completed by two monodentate bromide and two oxygen atoms from bridging dppeO2. Crystal data are as follows: C26-H24CuP2BnO2, 0.50 mm× 0.40 mm×0.40 mm, monoclin-ic, space group: C2/c, λ= 0.07107 nm(Mo Ka), a = 1.2286(2) nm, b=2.0555(8) nm, c = 1.0652(2) nm, β = 97.366(9)°, V = 2.668nm3, Z = 4, Dcalc = 1.628 g·cm-3, R = 0.066; Rw = 0.091.     

Direct potentiometric determination of tin(II) and (IV), antimony(III), thallium(III), rhenium(VII), and bismuth(III) with cetylpyridinium chloride

Summary The precipitation titrations of the following elements vs. cetylpyridinium chloride were investigated: Rhenium as perrhenate, tin as the (II) and (IV) species, antimony(III), thallium(III), and bismuth(III) as their halogen complexes. Optimum conditions for the determinations are described. Of the elements examined only thallium(III) also could be titrated potentiometrically vs. tetraphenylarsonium chloride. Titrations were monitored with a simple sensor consisting of a graphite rod coated with poly(vinyl chloride) and dioctylphthalate, and a double-junction reference electrode.

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Direkte potentiometrische Bestimmung von Zinn(II) und (IV), Antimon(III), Thallium(III), Rhenium(VII) und Bismut(III) mit Hilfe von Cetylpyridiniumchlorid

Zusammenfassung Die Fällungstitration der genannten Elemente mit Cetylpyridiniumchlorid wurde untersucht: Re als Perrhenat; Zinn in 3- und 4wertiger Form; Sb(III), Tl(III) und Bi(III) in Form ihrer Halogenkomplexe. Die optimalen Bedingungen werden mitgeteilt. Nur Thallium(III) kann auch potentiometrisch gegen Tetraphenylarsoniumchlorid titriert werden. Die Titrationen werden mit Hilfe eines einfachen Sensors kontrolliert, der aus einem mit Polyvinylchlorid und Dioctylphthalat überzogenen Graphitstab besteht sowie einer double-junction Bezugselektrode.

     

Synthesis,crystal structure and thermal stability of new copper(II) trichloroacetate complexes

We have synthesized two novel complexes of copper(II) trichloro acetate, Cu₂(CCl₃COO)₃(OH)(H₂O)₄·H₂O and Cu(CCl₃COO)₂(MeCN), and determined their crystal structures and thermal stability. While the complex with acetonitrile has a discrete binuclear paddle-wheel structure, typical of copper carboxylates, the aqua-hydroxo complex belongs to a novel unique chain–molecular type of basic copper complexes.     

Synthesis,characterizations and crystal structures of new antimony (III) complexes with dithiocarbamate ligands

Eight new antimony (III) complexes containing dithiocarbamate ligands (R₂NCS₂)₂SbBr [R₂NCS₂ = OC₄H₈NCS₂ (1), C₂H₅NC₄H₈NCS₂ (2), Me₂NCS₂ (3), C₄H₈NCS₂ (4)] and (R₂NCS₂)₃Sb[R₂NCS₂ = C₅H₁₀NCS₂ (5), Bz₂NCS₂ (6), Et₂NCS₂ (7), (HOCH₂CH₂)₂NCS₂ (8)] have been synthesized by the reactions of antimony (III) halides with dithiocarbamate ligands in 1:2 or 1:3 stoichiometries. All the complexes have been characterized by elemental analysis, melting point as well as spectral [IR and NMR (¹H and ¹³C)] studies. The crystal structures of complexes 1, 5 and 8 have been determined by X-ray single crystal diffraction, and their electrochemical character has also been studied.     

Crystallographic report: Chlorobis(pyrrolinedithiocarbamato)antimony(III)

The X‐ray crystal structure of Sb(S₂CN(CH₂)₄)₂Cl features a five‐coordinate geometry for antimony within a ClS₄ donor set, provides evidence for a stereochemical influence exerted by the lone pair of electrons on antimony, and shows no evidence for molecular aggregation. Copyright © 2003 John Wiley & Sons, Ltd.