Copper(II), nickel(II) and cobalt(II) complexes of 5,5-dimethylcyclohexane-1,2,3-trione-2-arylhydrazones

Summary Copper(II), nickel(II) and cobalt(II) perchlorate complexes of 5,5-dimethylcyclohexane-1,2,3-trione-2-(p-nitrophenyl-hydrazone) (HL¹), 5,5-dimethyl-cyclohexane-1,2,3-trione-2-(p-chlorophenylhydrazone) (HL²), 5,5-dimethylcyclohexane-1,2,3-trione-2-(o-chlorophenylhydrazone) (HL⁴), 5,5-dimethylcyclohexane-1,2,3-trione-2-(o-methylphenyl-hydrazone) (HL⁵) and 5,5-dimethylcyclohexane-1,2,3-trione-2-(m-methylphenylhydrazone) (HL⁶) have been prepared, and characterized using analytical, spectral and magnetic measurements. The data reveal that the reaction of Cu(ClO₄)₂ (1 mol) in EtOH, with all ligands, produces complexes of the type CuL(ClO₄)(H₂O).nH₂O. Nickel(II) and cobalt(II) perchlorates react only with HL¹ and HL² to produce the complexes ML(ClO₄)(H₂O)₃ (where M = Ni^II, L = L^– and L², M = Co^II, L = L¹) and Co(HL₂)₂-(ClO₄)₂.2H₂O. The spectral data show that the ligands behave as monobasic bidentate in their azo forms, except HL² which reacts with cobalt(II) as a neutral bidentate ligand in its hydrazone form.     

Etude des complexes sulfosalicylate de cuivre(III), nickel(II), cobalt(II) et uranyle(II) a l'aide d'une resine echangeuse de cations: Study of the sulphosalicylate complexes ofcopper(II), nickel(II), cobalt(II) and uranyl(II) by means of cation-exchange resins.

Study of the sulphosalicylate complexes of copper(II), nickel(II), cobalt(II) and uranyl(II) by means of cation-exchange resins.The conditional stability constants of the 1:1 complexes of the sulphosalicylate ions (L^3-) with copper(II), nickel(II), cobalt(II) and uranyl ions have been determined in a sodium perchlorate solution (0.1 M) and at various pH values by a cation-exchange method based on Schubert's procedure. The limits of application of the method are discussed. The variation with pH of the conditional stability constants can be explained by the existence of the complexes: CuH₂L, CuHL, CuL^-; NiH₂L⁺, NiHL, NiL^-; CoHL, CoL^-; UO₂H₂L⁺, UO₂HL, UO₂L^-, UO₂LOH^2-. The stability constants of these complexes are reported. Distribution diagrams of the various complexes of each element with pH and total concentration of sulphosalicylate parameters are given.     

Heteronuclear complexes of oxorhenium(V) with Fe(III), Co(II), Ni(II), Cu(II), Cd(II) and UO2(VI) and their biological activities

Heteronuclear complexes containing oxorhenium(V), with Fe(III), Co(II), Ni(II), Cu(II), Cd(II) and UO₂(VI) ions were prepared by the reaction of the complex ligands [ReO(HL¹)(PPh₃)(OH₂)Cl]Cl (a) and/or [ReO(H₂L²)(PPh₃)(OH₂)Cl]Cl (b), where H₂L¹?=?1-(2-hydroxyphenyl)butane-1,3-dione-3-(5,6-diphenyl-1,2,4-triazine-3-ylhydrazone) and H₃L²?=?1-(2-hydroxyphenyl)butane-1,3-dione-3-(1H-benzimidazol-2-ylhydrazone), with transition and actinide salts. Heterodinuclear complexes of ReO(V) with Fe(III), Co(II), Ni(II), Cu(II) and Cd(II) were obtained using a 1?:?1 mole ratio of the complex ligand and the metal salt. Heterotrinuclear complexes were obtained containing ReO(V) with UO₂(VI) and Cu(II) using 2?:?1 mole ratios of the complex ligand and the metal salts. The complex ligands a and b coordinate with the heterometal ion via a nitrogen of the heterocyclic ring and the nitrogen atom of the C=N⁷ group. All transition metal cations in the heteronuclear complexes have octahedral configurations, while UO₂(VI)?complexes have distorted dodecahedral geometry. The structures of the complexes were elucidated by IR, ESR, electronic and ¹H NMR spectra, magnetic moments, conductance and TG-DSC measurements. The antifungal activities of the complex ligands and their heteronuclear complexes towards Alternaria alternata and Aspergillus niger showed comparable behavior with some well-known antibiotics.     

Synthesis,structures, and urease inhibition of nickel(II), zinc(II), and cobalt(II) complexes with similar hydroxy-rich Schiff bases

Four new nickel(II), zinc(II), and cobalt(II) complexes, [Zn(L¹)₂]?·?H₂O (1), [Ni(L¹)₂]?·?H₂O (2), [Ni(L²)₂] (3), and [Co(L³)₂]?·?H₂O (4), derived from hydroxy-rich Schiff bases 2-{[1-(5-chloro-2-hydroxyphenyl)methylidene]amino}-2-methylpropane-1,3-diol (HL¹), 2-{[1-(2-hydroxy-3-methoxyphenyl)methylidene]amino}-2-ethylpropane-1,3-diol (HL²), and 2-{[1-(5-bromo-2-hydroxyphenyl)methylidene]amino}-2-methylpropane-1,3-diol (HL³) have been synthesized and characterized by elemental analyses, infrared spectroscopy, and single-crystal X-ray determination. Each metal in the complexes is six-coordinate in a distorted octahedral coordination. The Schiff bases coordinate to the metal atoms through the imino N, phenolate O, and one hydroxyl O. In the crystal structures of HL¹ and the complexes, molecules are linked through intermolecular O–H···O hydrogen bonds, forming 1-D chains. The urease inhibitory activities of the compounds were evaluated and molecular docking study of the compounds with the Helicobacter pylori urease was performed.     

Synthesis,characterization, DNA-binding,and antioxidant activities of four copper(II) complexes containing N-(3-hydroxybenzyl)-amino amide ligands

Four new substituted amino acid ligands, N-(3-hydroxybenzyl)-glycine acid (HL₁), N-(3-hydroxybenzyl)-alanine acid (HL₂), N-(3-hydroxybenzyl)-phenylalanine acid (HL₃), and N-(3-hydroxybenzyl)-leucine acid (HL₄), were synthesized and characterized on the basis of ¹H NMR, IR, ESI-MS, and elemental analyses. The crystal structures of their copper(II) complexes [Cu(L₁)₂]·2H₂O (1), [Cu(L₂)₂(H₂O)] (2), [Cu(L₃)₂(CH₃OH)] (3), and [Cu(L₄)₂(H₂O)]·H₂O (4) were determined by X-ray diffraction analysis. The ligands coordinate with copper(II) through secondary amine and carboxylate in all complexes. In 2, 3, and 4, additional water or methanol coordinates, completing a distorted tetragonal pyramidal coordination geometry around copper. Fluorescence titration spectra, electronic absorption titration spectra, and EB displacement indicate that all the complexes bind to CT-DNA. Intrinsic binding constants of the copper(II) complexes with CT-DNA are 1.32?×?10^6?M^?1, 4.32?×?10^5?M^?1, 5.00?×?10^5?M^?1, and 5.70?×?10^4?M^?1 for 1, 2, 3, and 4, respectively. Antioxidant activities of the compounds have been investigated by spectrophotometric measurements. The results show that the Cu(II) complexes have similar superoxide dismutase activity to that of native Cu, Zn-SOD.     

Synthesis,Structural Characterization,and Antimicrobial Activities of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) Complexes of Triazole‐based Azodyes

The synthesis and characterization of new transition metal complexes of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) with 3‐(2‐hydroxynaph‐1‐ylazo)‐1,2,4‐triazole ( HL¹ ) and 3‐(2‐hydroxy‐3‐carboxynaph‐1‐ylazo)‐1,2,4‐triazole ( HL² ) have been carried out. Their structures were confirmed by elemental analyses, thermal analyses, spectral and magnetic data. The IR and ¹H NMR spectra indicated that HL¹ and HL² coordinated to the metal ions as bidentate monobasic ligands via the hydroxyl O and azo N atoms. The UV‐Vis, ESR spectra and magnetic moment data revealed the formation of octahedral complexes [Mn L¹ (AcO)(H₂O)₃] ( 1 ), [Co L¹ (AcO)(H₂O)₃]·H₂O ( 2 ), [Mn L² (AcO)(H₂O)₃] ( 6 ) and [Co L² (AcO)(H₂O)₃] ( 7 ), [Ni L¹ (AcO)(H₂O)] ( 3 ), [Zn L¹ (AcO)(H₂O)]·H₂O ( 5 ), [Ni L² (AcO)(H₂O)] ( 8 ), [Zn L² (AcO)(H₂O)]·10H₂O ( 10 ) have tetrahedral geometry, whereas [Cu L¹ (AcO)(H₂O)₂] ( 4 ) and [Cu L² (AcO)(H₂O)₂]·5H₂O ( 9 ) have square pyramidal geometry.. The mass spectra of the complexes under EI‐con‐ ditions showed the highest peaks corresponding to their molecular weights, based on the atomic weights of ⁵⁵Mn, ⁵⁹Co, ⁵⁸Ni, ⁶³Cu and ⁶⁴Zn isotopes; besides, other peaks containing other isotopes distribution of the metal. Kinetic and thermodynamic parameters of the thermal decomposition stages were computed from the thermal data using Coats‐Redfern method. HL² and complexes 6 – 10 were found to have moderate antimicrobial activities against Staphylococcus aureus (gram positive), Escherichia coli (gram negative) and Salmonella sp bacteria, and antifungal activity against Fusarium oxysporum, Aspergillus niger and Candida albicans. Also, in most cases, metallation increased the activity compared with the free ligand.     

Metal complexes of sulfur-nitrogen chelating agents. Part 12. The chemistry of nickel(II), palladium(II), cobalt(II) and copper(II) complexes of N2S2 and N3S2 donor systems

Summary Nickel(II), palladium(II), cobalt(II) and copper(II) complexes of the ligandN,N-1,2-propane-bis(methyl 2-amino-cyclopent-1-ene-dithiocarboxylate) (H₂L¹),N,N-1,3-propane-bis(methyl 2-aminocyclopent-1-ene-dithiocarboxylate) (H₂L²) andN,N-[bis(methyl 2-aminocyclopent-1-ene-dithiocarboxylate)] diethylenetriamine (H₂L³) have been synthesised. Both H₂L¹ and H₂L² form complexes of the type ML, and all but the copper(II) complexes, are square planar. In the copper(II) complexes tetrahedral distortion is significantly more with CuL². From H₂L³ square planar complexes of the type [M(HL³)X] (M=Ni, X=Cl, Br, I or SCN; M=Pd, X=Cl or Br) have been obtained in which the donor unit involved is N₂SX. The composition of the cobalt(II) and copper(II) complexes is [M(H₂L³)X₂] (X=Cl or Br) which contain the chromophore [MN₃X₂].     

Complexes of sterically-hindered diaminophosphinothiolate ligands with Rh(I), Ni(II) and Pd(II)

Two new sterically demanding diaminophosphinothiolate ligands (HL¹ and HL²) have been prepared and the X-ray crystal structure of the Li salt of HL² has been determined. The complex [Pd(L¹)₂] was fully characterized, but in contrast to other phosphinothiolates, complexes with the M(L)₃ stoichiometry could not be prepared. Reaction of LH¹ with Ni(II) led to cleavage of the arythiolate group and isolation of a thiolate bridged dimer, confirmed by an X-ray crystal structure. The Rh(I) complexes [Rh(nbd)L] (L = L¹, L²) were characterized including an X-ray structure.     

Fluorescent UO2(II) and ZrO(II) complexes: Synthesis,structural characterization,fluorescence, DNA binding studies and biological applications in cell probing

A new series of UO2(II) and ZrO(II) azo‐complexes based on 5‐nitro‐8‐hydroxyquinoline; [UO₂(H₂L¹)(NO₃)EtOH] (1), [ZrO(H₂L¹)(NO₃)H₂O] (2), [UO₂(HL²)(NO₃)EtOH]3H₂O (3), [ZrO(HL²)(NO₃)EtOH] (4), [UO₂(HL³)(NO₃)(H₂O)₃]2H₂O (5) and [ZrO(HL³)(NO₃)EtOH] (6); have been synthesized. The structure of these complexes has been characterized using elemental analysis, thermal analysis, molar conductance, UV–vis, IR, electron impact mass, X‐ray powder diffraction and NMR spectra. The results revealed the formation of non‐electrolyte mononuclear complexes via the N atom of the azo group or of the quinoline ring and the oxygen atom of the deprotonated OH. Fluorescence properties of the synthesized complexes have been examined and the fluorescence quantum yield (Φ_f) has been determined. The complexes have been tested as cell staining and imaging under the fluorescent microscope. The data showed that complexes 1 and 2 efficiently stain the nuclei in addition to some focal cytoplasmic areas. Other than complexes 3 and 4 exclusively stained the nuclei. On the other hand, complexes 5 and 6 stained the cytoplasm exclusively. It has been demonstrated that complex 4 was the most effective in cell staining. The binding constant (Kb) with DNA was calculated using UV–vis absorption titration and fluorescence spectral methods. It was concluded that complex 4 can be used effectively as fluorescent probes in studying cell biology.     

Synthesis,characterization, crystal structure and toxicity evaluation of Co (II), Cu (II), Mn (II), Ni (II), Pd (II) and Pt (II) complexes with Schiff base derived from 2-chloro-5-(trifluoromethyl)aniline

A bidentate NO donor Schiff base, 2-(((2-chloro-5- (trifluoromethyl)phenyl)imino)methyl) phenol ( HL ¹ ) and its complexes [Co(L¹)₂(H₂O)₂] ( 1 ), [Cu(L¹)₂] ( 2 ), [Mn(L¹)₂(H₂O)₂] ( 3 ), [Ni(L¹)₂(H₂O)₂] ( 4 ), [Pd₂(L¹)₂(OAc)₂·1.16H₂O] ( 5 ), [Pt(L¹)₂] ( 6 ) were synthesized and characterized by different physico-chemical techniques including elemental and thermal analysis, magnetic susceptibility measurements, molar electric conductivity, IR, ¹H-NMR, ¹³C-NMR, UV–Vis, mass spectroscopies and X-ray powder diffraction (XRD). The molecular structures of ligand HL ¹ and two complexes ( 2 and 5 ) were confirmed by X-ray crystallography analysis on the monocrystal. In this complexes, the metal ions are in distorted square-planar environments. The copper (II) complex is mononuclear and crystallized in a monoclinic space group P21/c, whereas palladium (II) complex is dinuclear and crystallized in the trigonal crystal system R-3. The toxicity of the ligand and complexes was evaluated on both plant and animal cells, using the plant species Triticum aestivum L. and the crustacean Artemia franciscana Kellogg. At concentrations up to 100 μM the compounds presented very little toxicity on Artemia franciscana Kellogg. Moreover, the palladium (II) complex was devoid of any toxicity on the plant cells.     

Copper(II) Complexes of 3,4,5‐Trisubstituted Pyrazolates: In Situ Formation of Pyrazole Rings from Different Carbon Centers

The synthesis and characterization of two pyrazolate‐bridged dicopper(II) complexes, [Cu₂(L¹)₂(H₂O)₂](ClO₄)₂ ( 1 , HL¹=3,5‐dipyridyl‐4‐(2‐keto‐pyridyl)pyrazole) and [Cu₂(L²)₂(H₂O)₂](ClO₄)₂ ( 2 , HL²=3,5‐dipyridyl‐4‐benzoylpyrazole), are discussed. These copper(II) complexes are formed from the reactions between pyridine‐2‐aldehyde, 2‐acetylpyridine (for compound 1 ) or acetophenone (for compound 2 ), and hydrazine hydrate with copper(II) perchlorate hydrate under ambient conditions. The single‐crystal X‐ray structure of compound 1? 2 H₂O establishes the formation of a pyrazole ring from three different carbon centers through C? C bond‐forming reactions, mediated by copper(II) ions. The free pyrazoles (HL¹ and HL²) are isolated from their corresponding copper(II) complexes and are characterized by using various analytical and spectroscopic techniques. A mechanism for the pyrazole‐ring synthesis that proceeds through C? C bond‐forming reactions is proposed and supported by theoretical calculations.     

Size and stability of chelate rings in coordination compounds of cobalt(II), manganese(II), iron(III) and palladium(II) with vicinal oxime-imine ligands

Summary Two types of the Co^II complexes L¹Co (H₂L¹=N,N-ethylenebis(isonitrosoacetylacetoneimine) were prepared. In type (a) the chelate rings are five-membered whereas in type (b) they are six-membered. The type (b) complexes were converted to type (a) in refluxing solutions. Half-ionization of the ligand is observed in the complexes HL¹ Co(O₂CMe) and HL¹MnCl, where the chelate rings are five- and six-membered respectively. The octahedral complex L¹FeCl·H₂O has chelate rings of type (a) as does the complex L²Co (H₂L²=unsymmetric Schiff baseN,N-ethylene(isonitrosoacetylacetoneimineacetylacetoneimine). Twocis complexes (L_a ²L_b ³)Pd and (L_a ³)₂Pd are characterized (HL³=isonitrosoacetylacetoneimine, (a) and (b) denote the type of chelate ring). Structures for the metal complexes and the sizes of the chelate rings are suggested on the basis of analytical and spectral evidence.     

Self-assembled macrocyclic molecular squares of Ni(II) derived from carbohydrazones and thiocarbohydrazones: Structural and magnetic studies

Four novel molecular square grids were achieved by self-assembly using the flexible ligands bis(di-2-pyridyl ketone) thiocarbohydrazone (H₂L¹), bis(quinoline-2-carbaldehyde) thiocarbohydrazone (H₂L²), bis(di-2-pyridyl ketone) carbohydrazone (H₂L³) and bis(2-benzoylpyridine) carbohydrazone (H₂L⁴). Three complexes were given a general formula of [Ni(HL)]₄[PF₆]₄ · nH₂O and one [Ni₂(HL²)L²]₂(PF₆)₂ · 7H₂O. The MALDI-MS spectra reveal the formation of tetranuclear molecular squares. The square grid of the Ni(II) centers in all the complexes were organized by deprotonated ligands. The complex [Ni(HL¹)]₄[PF₆]₄ · 11H₂O crystallized as [Ni(HL¹)]₄(PF₆)₄ · 0.5 CH₃CH₂OH · 2.8H₂O and X-ray study revealed octahedral geometries around the Ni(II) centers. Variable temperature magnetic studies suggest intramolecular antiferromagnetic coupling between the Ni(II) electrons by a super exchange mechanism through intervening sulfur/oxygen atoms.     

Synthesis and study of cobalt(II), nickel(II), and copper(II) complexes with 4-(4-hydroxyphenyl)-1,2,4-triazole

New complexes of Co(II), Ni(II), and Cu(II) nitrates, chlorides, and perchlorates with 4-(4-hydroxyphenyl)-1,2,4-triazole (L) were obtained and examined by single-crystal X-ray diffraction, X-ray powder diffraction, and electronic absorption and IR spectroscopy. The cations of all the complexes have linear trinuclear structures. Ligand L is coordinated to the metal ions in a bidentate bridging fashion through the N(1) and N(2) atoms of the heterocycle. The coordination polyhedron of the metal atoms is a distorted octahedron. The molecular and crystal structures of the complexes [Co₃L₆(H₂O)₆](ClO₄)₆ · 3C₂H₅OH · 3.75H₂O and [M₃L₆(H₂O)₆](ClO₄)₆ · 6H₂O (M = Cu²⁺ and Ni²⁺) were determined.     

Cobalt(II), nickel(II), and copper(II) complexes of 14-membered hexaazamacrocycles: synthesis and characterization

Cobalt(II), nickel(II), and copper(II) complexes containing 5,12-di(4-bromophenyl)-7,14-dimethyl-1,2,4,8,9,11-hexaazacyclotetradeca-7,14-diene-3,10-dione (H₂L¹) and 5,12-diphenyl-7,14-dimethyl-1,2,4,8,9,11-hexaazacyclotetradeca-7,14-diene-3,10-dione (H₂L²) have been synthesized. All complexes were characterized by elemental analysis, MALDI TOF-MS spectrometry, and electronic absorption spectroscopy. The crystal structures of two compounds, [Cu₂(H₂L¹)Cl₄]_n and [NiL²], were determined by X-ray powder diffraction. In the polymeric [Cu₂(H₂L¹)Cl₄]_n, the Cu₂Cl₄ units and H₂L¹ molecules are situated on inversion centers. Each Cu(II) has a distorted trigonal-bipyramidal coordination environment formed by N and O from H₂L¹ [Cu–N 2.340(14)?Å, Cu–O 1.952(11)?Å], two bridging chlorides [Cu–Cl 2.332(5), 2.279(5)?Å] and one terminal chloride [Cu–Cl 2.320(6)?Å]. In the [NiL²] complex, the Ni(II) situated on inversion center has a distorted square-planar coordination environment formed by four nitrogens from L² [Ni–N 1.860(11), 1.900(11)?Å].     

Three new coordination complexes of cobalt(III), manganese(II), and copper(II) with N,N,O-donor hydrazone ligands: syntheses and structural characterizations

Three new coordination complexes, 2{[Co(L¹)₂]ClO₄} · 0.5CH₃OH (1), [Mn(L²)₂] (2), and [Cu(HL²)(L²)]ClO₄ · 2H₂O (3) have been synthesized from two tridentate N,N,O-donor hydrazone ligands HL¹, 2-acetylpyridine-salicyloylhydrazone, and HL², 2-benzoylpyridine-salicyloylhydrazone, respectively and thoroughly characterized by elemental analysis, FT-IR, UV–Vis, electrochemical, and room temperature magnetic susceptibility measurements. Structures of the complexes have been unequivocally established by single crystal X-ray diffraction technique. Structural analysis reveals that 1 consists of two chemically similar but crystallographically independent cationic [Co(L¹)₂]⁺ units and 2 consists of a neutral [Mn(L²)₂] molecule while 3 consists of a cationic [Cu(HL²)(L²)]⁺ unit. Metal ions display distorted octahedral geometry in 1 and 2 while in 3 it shows a distorted square pyramidal geometry. Ligand conformations around the metal ions are stabilized by the presence of intra-ligand hydrogen bonding in all the complexes. Structure of 3 reveals that a perchlorate ion linked to the complex by hydrogen bonding via a water molecule.     

Redox-active metal(II) complexes of sterically hindered phenolic ligands: Antibacterial activity and reduction of cytochrome c. Part II. Metal(II) complexes of o-diphenol derivatives of thioglycolic acid

The synthesis and physico-chemical characterization of Fe(II) and Mn(II) complexes of 2-[4,6-di(tert-butyl)-2,3-dihydroxyphenylsulfanyl]acetic acid (HL^I) and 2-[4,6-di(tert-butyl)-2,3-dihydroxyphenylsulfinyl]acetic acid (HL^II) were carried out. The investigation of the molecular and electronic structure of Cu(II), Ni(II), Zn(II), Fe(II) and Mn(II) complexes has been performed within the density functional theory (DFT) framework. The computed properties were compared to the experimental ones, and molecular structures of the compounds were proposed based on the array of spectral data and quantum chemical calculations. Antibacterial activity of the Fe(II) and Mn(II) complexes was evaluated in comparison with Cu(II), Co(II), Ni(II) and Zn(II) complexes and three standard antibiotics; it was found to follow the order: (1) Сu(L^I)₂ > Mn(L^I)₂ > HL^I > Ni(L^I)₂ > Zn(L^I)₂ > Fe(L^I)₂ > Co(H₂O)₂L^I; (2) Cu(L^II)₂ > Сo(L^II)₂ > Ni(L^II)₂ > Mn(H₂O)₂(L^II)₂ > Fe(L^II)₂ > HL^II > Zn(L^II)₂; their reducing ability (determined electrochemically) followed the same order. Spectrophotometric investigation was carried out in order to estimate the rate of the reduction of bovine heart сytochrome c with the ligands and their metal(II) complexes. The complexes Сu(L^I)₂, Mn(L^I)₂ and Co(L^II)₂ with the high reducing ability were found to be characterized by the highest rates of Cyt с reduction. NADPH:cytochrome P450-reductase had no substantial effect on the rate of сytochrome c reduction with HL^I and HL^II ligands.     

Synthesis,structure, and solvent-extraction properties of tridentate oxime ligands and their cobalt(II), nickel(II), copper(II), zinc(II) complexes

Synthesis of four different types of ligands Ar[COC(NOH)R] _n (Ar = biphenyl, n = 1, HL¹; Ar = biphenyl, n = 2, H₂L²; Ar = diphenylmethane, n = 1, HL³; Ar = diphenylmethane, n = 2, H₂L⁴; R = furfurylamine in all ligands) and their dinuclear Co²⁺, Ni²⁺, Cu²⁺, and Zn²⁺ complexes is reported herein. These compounds were characterized by elemental analysis, ICP-OES, FT-IR spectra, and magnetic susceptibility measurements. The ligands were further characterized by ¹H NMR. The results suggest that dinuclear complexes of HL¹ and HL³ have a metal to ligand mole ratio of 2: 2 and dinuclear complexes H₂L² and H₂L⁴ have a metal to ligand mole ratio of 2: 1. Square pyramidal or octahedral structures are proposed for complexes of oxime ligands. Furthermore, extraction abilities of the four ligands were also evaluated in chloroform using selected transition metal picrates such as Mn²⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺, Cd²⁺, Hg²⁺, Pb²⁺. The ligands show strong binding ability towards Hg²⁺ and Cu²⁺ ions.     

Synthesis,spectroscopic and the biological activity studies of thiosemicarbazones containing ferrocene and their copper(II) complexes

Two Schiff bases, 1-acetylferrocene thiosemicarbazone (HL¹) and 1,1′-diacetyl-ferrocene dithiosemicarbazone (H₂L²) and their copper(II) complexes were prepared and characterized by elemental analysis, magnetic susceptibility, conductivity, and spectral (IR, UV–Vis, ESR) measurements The IR spectra showed that HL¹ acts as neutral or monobasic bidentate ligand, coordinating to copper(II) through either thiono- or thiolo-sulphur and azomethine-N atoms, whereas H₂L² is a neutral or dibasic mononucleating or binucleating quadridentate ligand coordinating through the same atoms. Other spectral measurements indicate that complexes [(L¹)₂Cu], [(L²)Cu] and [(HL¹)₂Cu]X₂, X?=?Cl, Br or ClO₄ have square-planar geometry around copper(II) while [(HL¹)CuX₂] and [(H₂L²)Cu₂X₄], X?=?Cl or Br, have distorted tetrahedral geometry. The biological activity studies of the complexes and the free ligands towards two gram positive and two gram negative bacteria and one fungal species have been studied and the potential is related to the nature and structure of the tested compounds.     

Complexation en solution aqueuse des ions magnesium(II), manganese(II), nickel(II), cuivre(II) et plomb(II) avec la s-carboxymethyl-l-cysteine: Complex formation of magnesium(II), manganese(II), nickel(II), copper(II) and lead(II) with S-carboxymethyl-L-cysteine in aqueous solution

Complex formation of magnesium(II), manganese(II), nickel(II), copper(II) and lead(II) with S-carboxymethyl-L-cysteine in aqueous solution.The complex formation between Mg(II), Mn(II), Ni(II). Cu(II), Pb(II) ions and S-carboxy-methyl-l-cysteine (H₂A) has been studied by measurement of pH at 25°C and constant ionic strength (1 M NaClO₄). Although no interaction occurs with Mg(II), this work provides evidence for a variety of complexes: MnA; CuHA⁺; CuA; CuA₂^2-; NiHA⁺; NiA; NiA₂^2-; PbHA⁺; PbA et PbA(OH)^-. The overall formation constants of all these species are computed and refined. The results allow the determination of the distribution of the complexes as a function of pH; some structural features of the metal complexes in solution are indicated.