Complexes of N-nicotinoyl-N′-2-furanthiocarbohydrazide with oxovanadium(IV), manganese(II), iron(II & III), cobalt(II), nickel(II), copper(II) and zinc(II)

A new potential tetradentate ligand, N-nicotinoyl-N-2-furanthiocarbohydrazide (H₂Nfth), and its complexes with VO^IV, Mn^II, Fe^II,III, Co^II, Ni^II, Cu^II and Zn^II have been prepared and characterized by elemental analyses, magnetic susceptibility measurements, u.v.–vis, i.r., n.m.r., ES⁺ and FAB mass spectral data. The room temperature e.s.r spectra of the VO^IV and Fe^III complexes yield g values, characteristic of octahedral complexes. The Mössbauer spectra of [Fe(HNfth)₂] and [Fe₂(Nfth)₃] at room temperature and at 78 K suggest the presence of high-spin iron(II) and iron(III), respectively. The complexes are electrically insulating at room temperature, however, their conductivities increase as the temperature increases from 333–383 K, with a band gap of 0.46–0.77 eV, indicating their semiconducting behaviour. H₂Nfth and its soluble complexes have been screened against several bacteria and fungi.     

Complex formation of Cu(II), Ni(II), Zn(II), Co(II), and Cd(II) acetates with 3,3′,4,4′,5,5′-hexamethyldipyrrolylmethene

The reactions of complex formation of Cu(II), Co(II), Zn(II), Ni(II), and Cd(II) acetates with 3,3′,4,4′5,5′-hexamethyl-2,2′-dipyrrolylmethene (HL) in DMF were studied by the electronic spectroscopy and calorimetric titration methods at 298.15 K. The main products of the above reactions are [ML₂] chelates. In the case of Cu and Ni salts, the process occurs through the spectrally recorded stage of formation of the heteroligand [ML(AcO)] complexes. The reaction with Cd acetate terminates at the stage of the heteroligand complex formation due to the large radius and decreasing electron affinity of the Cd²⁺ ion. The effect of the metal nature appears in the increasing thermodynamic stability of single-type complexes in the series [ML₂]: Ni(II) < Zn(II) < Co(II) < Cu(II) and [ML(AcO)]: Cd(II) < Ni(II) < Cu(II).     

β-diketone complexes of manganese(II), cobalt(II), nickel(II) and palladium(II)

Summary The reactions of manganese(II), cobalt(II) and nickel(II) acetates (1 mole) with antipyrine-4-azo--ethylcyanoacetate (HL¹) and antipyrine-4-azo--acetylacetone (HL²) (1 mole) produce complexes of the M(L)₂ type. K₂PdCl₄ (1 mole) reacts with HL¹ and HL² (1 mole) to yield complexes of the general formula PdLCl, the ligands behaving as monobasic tridentates. The electronic spectral and magnetic data show the complexes to be high-spin octahedral, whereas the palladium(II) complexes are diamagnetic square planar. The complexes were characterized by elemental analyses, conductance measurements and i.r. and electronic spectra as well as magnetic susceptibility measurements and thermal (t.g.a. and d.t.a.) analysis.Nuclear Material Authority.     

Aqueous Equilibrium and Solution Structural Studies of the Interaction of N,N′-bis(4-imidazolymethyl)etylenediamine with Ca(II), Cd(II), Co(II), Cu(II), Mg(II), Mn(II), Ni(II), Pb(II) and Zn(II) Metal Ions

Divalent metal complexes of N,N′-bis(4-imidazolymethyl)etylenediamine (EMI) have been studied using potentiometric and spectroscopic techniques (UV-Vis and NMR methods) in aqueous 0.1 mol⋅L⁻¹ KCl supporting electrolyte at 25 °C. Final models and overall stability constants for the complexes of Ca(II), Cd(II), Co(II), Cu(II), Mg(II), Mn(II), Ni(II), Pb(II) and Zn(II) have been established by potentiometry for all M(II)–EMI systems, except for Co(II)–EMI. The data revealed that EMI forms ML complexes with all M(II)–EMI systems, which is the dominant species over a wide range of pH except for the Ca(II)–EMI and Mg(II)–EMI systems. Formation of the MnHL complex was also found for Mn(II)–EMI solutions. In addition, the UV-Vis and ¹H NMR results allowed us establish the coordination modes for the metal complexes between EMI with Cd(II), Cu(II), Ni(II) and Zn(II).     

Preparation, spectral and thermal properties of Co(II), Ni(II), Cu(II), Zn(II), and Cd(II) complexes with iodosubstituted 2,2′-dipyrrolylmethene

Complexes [ML₂] of cobalt(II), nickel(II), copper(II), zinc(II), and cadmium(II) with asymmetrically substituted (E)-3-ethyl-5-[(4-iodo-3,5-dimethyl-2H-pyrrol-2-ylidene)methyl]-2,4-dimethyl-1H-pyrrole (HL) have been prepared and characterized for the first time. The spectral properties, stability in solutions and in the solid phase at elevated temperature of the complexes have been studied. The effects of complexing metal ion and the reaction medium on the spectral luminescent properties (absorptivity, quantum yield, fluorescence lifetime, and the radiation constant) and on thermal destruction of the [ML₂] complexes have been discussed.     

Complexes of N-phenyl-N′-2-furanthiocarbohydrazide with oxovanadium(IV), manganese(III), iron(III), cobalt(II), nickel(II), copper(II) and zinc(II)

A new ligand, N-phenyl-N -2-furanthiocarbohydrazide (HPhfth), and its complexes with VO^IV, Mn^III, Fe^III, Co^II, Ni^II, Cu^II and Zn^II have been prepared and characterized by elemental analyses, magnetic susceptibility measurements, i.r., n.m.r., u.v.–vis., mass and FAB mass spectral data. The room temperature e.s.r. spectra of the VO^IV, Fe^III and Cu^II complexes yield <g> values characteristic of square pyramidal VO^IV, octahedral Fe^III and square planar Cu^II, respectively. The Ni^II and Cu^II complexes semiconduct, but the Zn^II complex is an insulator at room temperature. However, the conductivity increases as the temperature increases from 303–383 K, with a band gap of 0.21–1.01 eV. HPhfth and its soluble complexes have been screened against several bacteria and fungi.     

Elektrophorese der halogenokomplexe von Hg(II), Bi(III), Cd(II), Pb(II) und -Cu(II) : Chlorokomplexe in chlorwasserstoffsäure

An apparatus for heavy-current and high-tension electrophoresis on filter paper is described This apparatus enables one to avoid the difficulties that occur in electrophoresis in base electrolytes that are highly concentrated or show greater electric conductivity The zones migrate along the paper strips with constant speed and, consequently, it is possible to measure the mobility The effective length of the filter paper strips is 660 mm Correction of the apparent mobility in the porous adsorbent is treated thoroughly.Diagrams of the electrophoretic mobility of the chloro-complexes of Hg(II), Bi(III), Cd(II), Pb(II), and Cu(II) in hydrochloric acid, are given in the experimental part The concentration of the hydrochloric acid varied between 0.1N and 6N In 6N HCl all the metals investigated are present asani onic complexes. Hg, Bi.Cd, and Pb chloro-complexes show a pronounced maximum of mobility in the anionic range. The sequence of the zones in the direction anode to cathode is Hg, B1, Cd, Pb, Lu al 0.1–2.3N HCl and B1, Hg, Cd, Pb.Cu at2.3–6N HCl.Finally, the electrophoretic separation of a mixture of Hg, Bi, Cd, Pb, Cu in 1N, 2N and 4N HCl is illustrated Complete separation of the zones was achieved in each experiment     

Copper(II), nickel(II), cobalt(II) and oxovanadium(IV) complexes of substituted β-hydroxyiminoanilides

Complexes of the general formula, ML₂ [M = Cu^II, Ni^II, Co^II and OV^IV; L = 1,2,3,5,6,7,8,8a-octahydro-3-hydroxyimino-N-(4-X-phenyl)-l-phenyl-5-(phenylmethylene)-2-naphthalenecarboxamide (X = H, Me, OMe, Cl)] have been prepared and characterized on the basis of elemental analysis, magnetic moments and i.r., e.p.r. and electronic spectra. These metal complexes contain the N₄ chromophore with the ligand coordinating through nitrogens of the azomethine and deprotonated anilide functions. C.v. measurements indicate that the copper(II) complexes are quasi-reversible in acetonitrile solution. Square planar and square pyramidal structures are assigned respectively to the copper(II) and oxovanadium(IV) complexes, whereas tetrahedral geometry is assigned to the nickel(II) and cobalt(II) complexes. Deprotonated anilide nitrogen is involved in coordination and the presence of an electron-donating group para to the anilide function decreases the ΔE values of the d–d transitions while the value is found to increase when electron-withdrawing groups are substituted. Line spacing in the e.p.r. spectra of the copper(II) and oxovanadium(IV) complexes increases when methyl group is para to the anilide group, and decreases when this group is replaced by methoxy or chloro. The ν(C–N) of the anilide group and the ν(C-N) of the azomethine function of the oxime metal complexes are metal-sensitive and the blue shift for the above stretching frequencies follows the order: copper(II) > oxovanadium(IV) > nickel(II) ≈ cobalt(II). This revised version was published online in June 2006 with corrections to the Cover Date.     

Complex Species in Aqueous Solutions of 4-Chloro-1,2-Phenylenediamine-N,N,N′,N,'-Tetraacetic Acid with Magnesium(II), Calcium(II), Strontium(II), Barium(II), Zinc(II) and Cadmium(II)

Abstract

The coordination in aqueous solution of 4-chloro-1,2-phenylenediamine-N',N',N',N'-tetraacetic acid (4-Cl-o-PDTA) with Be(II) and with the transition metal cations cobalt(II), nickel(II) and copper(II) was reported in earlier publications.^1,2 In this note a study is presented of the coordination in aqueous solution (25°C, 1 = 0.1 M in KC1) of 4-CI-o-PDTA acid with magnesium(II), calcium(II), strontium(II), barium(II), zinc(II) and cadmium(II).     

Mixed-ligand complexes of iron(II), iron(III), copper(II), and cobalt(II) with pyrazolonic and 2,2′-bipyridine ligands

New mixed-ligand complexes, [M₂(BAMP)(bipy)₂][MCl₄]₂, M=Co⁺²(1), Cu⁺²(2), [M₂(TAMEN)(bipy)₂][MCl₄]₂, M=Fe⁺²(3), Co²⁺(4), and [Fe₂(TAMEN)(bipy)₂][FeCl₆]₂ (5), where BAMP and TAMEN stand for the Mannich bases N,N′-bis(antipyryl-4-methylene)-piperazine and N,N′-tetra(antipyryl-4-methylene)-1,2-ethane-diamine, respectively, have been obtained and characterized by elemental analyses, conductometric and magnetic susceptibility measurements at room temperature, mass spectrometry, UV-Vis, infrared, and mass spectroscopy, and ¹H NMR spectra for the ligands.     

Syntheses and structural characterizations of a new benzyl(4-methoxyphenyl)dithiophosphinic acid and its Ni(II), Co(II), Zn(II), Cd(II), and Ni–pyridine complexes

Benzyl(4-methoxyphenyl)dithiophosphinic acid (HL) was obtained as solid and was treated with the NiCl₂6H₂O, CoCl₂6H₂O, ZnCl_2, and CdCl₂ to prepare its Ni(II), Co(II), Zn(II), and Cd(II) complexes. The nickel complex was further treated with pyridine which led to the formation of octahedral dipyridine derivative. HL was obtained through the addition reaction of the perthiophosphonic acid anhydride Lawesson reagent, (LR), [2,4-bis(4-methoxyphenyl)-1,3,2,4-dithiadiphosphetane-2,4-disulfide], with the corresponding Grignard compound (benzylmagnesium bromide) in diethyl ether medium.

The complexes were all of the stoichiometry of [M(L)₂]_x, with x = 1 for M = Ni²⁺ and x = 2 for M = Co²⁺, Cd²⁺ and Zn²⁺. The coordination geometry was square planar in the nickel(II) complex and tetrahedral in the others. Similar to many other nickel(II) complexes, the Ni(L)₂ reacts reversibly with pyridine to yield the octahedral complex ({(Py)₂Ni(L)₂}).

The compounds were characterized by elemental analysis; MS, FTIR, and Raman spectroscopies. The magnetic susceptibilities of the complexes were measured to confirm the hybridization patterns and the geometries. Single-crystal X-ray analyses of Ni(L)₂ and [Co(L)₂]₂ complexes were also carried out to prove the molecular topologies.     

Potentiometric determination of the formation constants for complexes of 3,2′,2″-triaminopropyldiethylamine with cobalt(II), nickel(II), copper(II), zinc(II) and cadmium(II)

The tripodal tetraamine ligand N{(CH₂)₃NH₂}{(CH₂)₂NH₂}₂ (pee), has been investigated as an asymmetrical tetraamine chelating agent for Co^II, Ni^II, Cu^II, Zn^II and Cd^II. The protonation constants for this ligand and the formation constants for its complexes have been determined potentiometrically in 0.1 M KCl at 25 °C. The successive protonation constants (log K _n ) are: 10.22, 9.51, 8.78 and 1.60 (n = 1–4). One complex with formula M(pee)²⁺ (M = Co, Ni, Cu, Zn and Cd) is common to all five metal ions and the formation constant (log _ML) is: 12.15, 14.17, 16.55, 13.35 or 9.74, respectively. In addition to the simple complexes, Co^II, Cu^II and Zn^II also give hydroxo complexes, and Cu^II and Ni^II give complexes with monoprotonated pee. [Zn(pee)](ClO₄)₂ and [Cd(pee)Cl](ClO₄) complexes were isolated and are believed to have tetrahedral and trigonal-bipyramidal structures, respectively.     

Copper(II), zinc(II), and cadmium(II) coordination polymers with 2-methylglutarato and 4,4′-dipyridyldisulfide

Three new coordination polymers of copper(II), zinc(II) and cadmium(II), Cu(H₂O)(Dpds)(2-MGA) (I), [Zn(Dpds)(2-MGA)] · 1.25H₂O (II) and [Cd(H₂O)(Dpds)(2-MGA)] · 0.25H₂O (III) (Dpds = 4,4′-dipyridyldisulfide, H₂MGA = (RS)-2-methyl glutaric acid), have been synthesized and characteried by X-ray single crystal structure determination. The Cu atoms in I are alternately bridged by Dpds ligands and 2-methylglutarato ligands to generate 1D chain. The resulted chains are assembled via S...S weak interactions into 2D layers, which are through twofold 2D parallel/2D parallel mode inclined interpenetration to induce 3D supramolecular architecture. In II, the ZnN₂O₂ tetrahedras are bridged by 2-MGA anion and Dpds ligands to form 2D (4,4) networks, which are assembled via hydrogen bonds to 3D supramolecular architecture. The centrosymmetric binuclear units Cd₂(2-MGA)₂ in III are bridged by Dpds ligands to form 1D repeated rhomboids chains, which are interlinked via S...S weak interactions into 2D layer, and the resulting 2D sheets are inclined parallel into 3D network.     

X-ray study of volatile Ni(II), Cu(II), and Pd(II) complexes of β-ketoimine pivalyltrifluoroacetone

Synthesis of volatile complexes based on -ketoimine pivalyltrifluoroacetone, C(CH₃)₃C(NH)CH₂COCF₃, is described. The general formula of the complexes is M(L)₂, where M = Cu, Ni, Pd. Complexes of this kind with Ni and Pd were obtained for the first time. The Cu and Pd complexes were found to be isostructural. A comprehensive crystal-chemical study showed that all structures are molecular and built of trans-complexes. The central atom has a square plane environment. The average M-O and M-N distances are nearly equal in all compounds: 1.84 , 1.92 , and 1.98 for Ni, Cu, and Pd complexes, respectively; the mean values of the O-M-N chelate angles are 93.4°, 91.9°, and 92.7°, respectively.Original Russian Text Copyright © 2004 by I. A. Baidina, G. I. Zharkova, N. V. Pervukhina, S. A. Gromilov, and I. K. IgumenovTranslated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 4, pp. 713–722, July–August, 2004.This revised version was published online in April 2005 with a corrected cover date.     

Which one among Zn(II), Co(II), Mn(II), and Fe(II) is the most efficient ion for the methionine aminopeptidase catalyzed reaction?

The catalytic hydrolysis of a methionyl-peptide substrate by a methionine aminopeptidase active site model cluster was investigated at the DF/B3LYP level of theory, in the gas-phase and in the protein environment. Zn(II), Co(II), Mn(II), and Fe(II) transition metals were examined as the potential catalytic metals of this enzyme involved in protein maturation. Two different mechanisms in which Glu204 was present as protonated or deprotonated residue were considered. The energetic profiles show lower barriers as the protonated glutamate is involved. The rate-determining step of the hydrolysis reaction is always the nucleophilic addition of the hydroxide on substrate carbon, followed by less energetically demanding methionine-peptide C-N bond scission. The lowest activation energy is obtained in the case of zinc dication while the other metals show very high energetic barriers, so that methionine aminopeptidase can be in principle recognized as a dizinc enzyme.     

Microwave assisted synthesis and characterization of N,N′-bis(salicylaldehydo)ethylenediimine complexes of Mn(II), Co(II), Ni(II), and Zn(II)

Microwave chemistry is a green chemical method that improves reaction conditions and product yields while reducing solvent amounts and reaction times. The main aim of this article is to synthesize the tetradentate N₂O₂ ligand [HO(Ar)CH=N–(CH₂)₂–N=CH(Ar)OH] and manganese(II), cobalt(II), nickel(II), and zinc(II) complexes of the type ML by classical and microwave techniques. The resulting Schiff base and its complexes are characterized by ¹H NMR, infrared, elemental analysis, and electronic spectral data. The ligand and its Co(II) and Mn(II) complexes were further identified by X-ray diffraction and mass spectra to confirm the structure. The results suggest that the metal is bonded to the ligand through the phenolic oxygen and the imino nitrogen.     

Complexation between decamethyl-3,3′-bis(dipyrrolylmethene) and zinc(II), copper(II), and cobalt(II) acetates

Decamethyl-3,3′-bis(dipyrrolylmethene) dihydrobromide H₂L · 2HBr (H₂L is bis(3,4,7,8,9-pentamethylpyrrol-3-yl)methane), which is the simplest representative of a novel class of oligo(dipyrrolylmethenes) belonging to chromophore chelating nonmacrocyclic ligands, were examined by ¹H NMR, IR, and electronic absorption spectroscopy. Complexation reactions of H₂L · 2HBr with M(AcO)₂ (M = Zn(II), Cu(II), and Co(II)) in DMF at 298.15 K were monitored by electronic absorption spectroscopy and studied by the molar ratio method. The thermodynamic constants K ⁰ of these reactions were estimated. The d metal ions coordinate H₂L to give the binuclear homoleptic complexes [M₂L₂]. The reactions proceed through the intermediate binuclear heteroleptic complex [M₂L(AcO)₂] detected by spectroscopic methods. The thermodynamic stabilities of [M₂L₂] and [M₂L(AcO)₂] increase when moving from Cu(II) to Zn(II) and Co(II). The probability of formation and stability of [M₂L₂] containing 3,3′-bis(dipyrrolylmethene) are substantially higher than those of analogous complexes with the 2,2′-isomer (decamethyl-2,2′-biladienea, c). The low K ⁰ values for the complexation between H₂L and Cu(AcO)₂ are due to slow oxidation of the biladiene ligand into a bilatriene with participation of Cu²⁺ ions.     

Antimicrobial studies of N - N ′-dicarboxydiethyloxamide and its Co(II), Ni(II), Cu(II) and Zn(II) complexes

Neutral complexes of Cu(II), Ni(II), Co(II), and Zn(II) have been synthesized from the oxamide-based ligand derived from leucine and diethyloxalate. The structural features have been deduced from their microanalytical, IR, UV/Vis, mass, ¹H and ¹³C NMR spectral data. The Co(II) and Ni(II) chelates have octahedral geometries and the Cu(II) chelate is a square-pyramidal geometry. The non-electrolytic and monomeric nature of the complexes is shown by their magnetic susceptibility and low conductance data. The biological activities of the ligand and its metal chelates against gram-positive and negative bacteria and fungi are also reported. All the compounds are antimicrobially active and show higher activity than the free ligand.     

2,9-二甲基-1,10-菲咯啉的α-氨甲基吡啶衍生物的合成表征及其Mn(II),Co(II),Ni(II),Cu(II),Zn(II)配合物稳定性研究

以2,9-二甲基-1,10-菲咯啉为初始原料,合成了2,9-二甲基-1,10-菲咯啉的α-氨甲基吡啶衍生物-N,N'-二(2'-吡啶基)甲基-1,10-菲咯啉-2,9-二甲胺(L).该配体经过元素分析、红外光谱、核磁共振氢谱表征.在25±0.1℃、I=0.1mol·dm-3NaNO3的条件下,用pH电位滴定法测定了该配体在水溶液中的质子化常数及其分别与Mn(II),Co(II),Ni(II),Cu(II)和Zn(II)的配合物的稳定常数,提出了配合物的可能结构.进一步讨论了相应稳定常数较大的内在原因.     

Hydrogen-bonded networks based on manganese(II), nickel(II), copper(II) and zinc(II) complexes of N,N′-dimethylurea

A project related to the crystal engineering of hydrogen-bonded coordination complexes has been initiatied and some of our first results are presented here. The compounds [Mn(DMU)₆](ClO₄)₂ (1), [Ni(DMU)₆](ClO₄)₂ (2), [Cu(OClO₃)₂(DMU)₄] (3) and [Zn(DMU)₆](ClO₄)₂ (4) have all been prepared from the reaction of N,N-dimethylurea (DMU) and the appropriate hydrated metal perchlorate salt. Crystal structure determinations of the four compounds demonstrate the existence of [M(DMU)₆]²⁺ cations and ClO₄ ^– counterions in (1), (2) and (4), whereas in (3) monodentate coordination of the perchlorate groups leads to molecules. The [M(DMU)₆]²⁺ cations and ClO₄ ^– anions self-assemble to form a hydrogen-bonded one-dimensional (1D) architecture in (1) and different 2D hydrogen-bonded networks in (2) and (4). The hydrogen bonding functionalities on the molecules of (3) create a 2D structure. The complexes were also characterised by room-temperature effective magnetic moments and i.r. studies. The data are discussed in terms of the nature of bonding and the known structures.