Synthesis and Characterization of Ni(II), Cu(II), Zn(II) and Cd(II) Complexes of a New Vic-Dioxime Ligand

In this study, 1,2-dihydroxyimino-3,7-di-aza-9,10-O-α-methyl benzal decane (LH₂) was synthesized starting from 1,2-O-α-methyl benzal-4-aza-7-amino heptane (RNH₂) and antichloroglyoxime. With this ligand, complexes were synthesized using Ni(II) and Cu(II) salts with a metal:ligand ratio of 1:2. However, the reaction of the ligand with salts of Zn(II) and Cd(II) gave products with metal:ligand ratio of 1:1. Structures of the ligand and its complexes are proposed based on elemental analyses, IR, ¹³C- and ¹H-NMR spectra, magnetic susceptibility measurements and thermogravimetric analyses (TGA).     

Complexing properties of methyl and phenyl glycine derivatives in their compounds with H+, Ni(II), Cu(II), and Zn(II)

The influence of the solvent and the substituents on the complexing properties of methyl and phenyl glycine derivatives is discussed. On the basis of a computer analysis of potentiometric titration results, the composition and the stability constants of the complexes ofN-methylglycine,N,N-dimethylglycine,N-phenylglycine and phenylglycine with H⁺ and with Ni(II), Cu(II), Zn(II) were determined. The ligand-metal coordination mode as well as the zwitterion level in percent in ligand/proton systems were determined by spectral analyses and equilibria studies.

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Komplexbildung der Methyl- und Phenylglycin-Derivate in ihren Verbindungen mit dem Proton und Ni(II), Cu(II) und Zn(II)

Zusammenfassung Der Einfluß des Lösungsmittels und der Substituenten auf die komplexbildenden Eigenschaften der Methyl- und Phenylglycin-Derivate wird diskutiert. Anhand einer Computer-Analyse von potentiometrischen Daten wurden die Zusammensetzung und die Beständigkeitskonstanten der Komplexe vonN-Methylglycin,N,N-Dimethylglycin,N-Phenylglycin und Phenylglycin mit H⁺, Ni(II), Cu(II) und Zn(II) festgestellt. Mittels spektroskopischer Methoden und Gleichgewichtstudien wurde der Koordinationstyp des Liganden mit dem Metall festgestellt sowie der Prozentanteil des Zwitterions im Ligand/Proton-System.

     

Separation of Ga(III) from Cu(II), Ni(II) and Zn(II) in aqueous solution using synthetic polymeric resins

Poly (acrylamide-acrylic acid-dimethylaminoethylmethacrylate), p(AM-AA-DMAEM) and Poly(acrylamide-acrylic acid)-ethylenediaminetetracetic acid disodium, p(AM-AA)-EDTANa₂ were prepared by gamma radiation-induced template polymerization technique and used for the separation of Ga (III) from Cu (II), Ni (II), and Zn (II) in aqueous media. The effect of pH and contact time on the separation process was studied. The optimum pH value for the separation process is 3–3.5. The result shows that Ga (III) is first extracted while Cu (II), Ni (II) and Zn(II) are slightly extracted at this pH value. The recovery of metals using HCl, HNO₃ and H₂SO₄ has been studied. The resins may be regenerated using 2M HCl solutions.      

Polarized spectroscopy and hybrid materials of chiral Schiff base Ni(II), Cu(II), Zn(II) complexes with included or separated azo-groups

Chiral Schiff base complexes containing azo-groups, bis(N-R-1-naphtylethyl-4-phenyldiazenylsalicydenaminato) nickel(II), copper(II), and zinc(II) complexes affording a distorted square planar trans-[MN₂O₂] coordination geometry were prepared newly. Organic/inorganic hybrid materials in polymethylmethacrylate (PMMA) cast films of them (a containing type) or the analogous chiral Schiff base complexes, bis(N-R-1-phenylethyl-3,5-dichlorosalicydenaminato) nickel(II), copper(II), and zinc(II), and azobenzene (AZ) (a separated type) were assembled for comparison of polarized UV light induced molecular arrangement caused by Weigert effect. Investigation of parameters for optical anisotropy of metal complexes as well as AZ suggested that the degree of increasing optical anisotropy of the containing type is higher than that of the separated type based on π-π^∗ (of which characteristic band appeared around 380 nm), n-π^∗, and d-d bands of polarized absorption electronic spectra. Rigid nickel(II) or zinc(II) complexes are easy to increase optical anisotropy than flexible copper(II) complexes for both types.     

The role of chiral dopants in organic/inorganic hybrid materials containing chiral Schiff base Ni(II), Cu(II) and Zn(II) complexes

Chiral Schiff base complexes containing azo-groups, bis(N-R-1-cyclohexylethyl-4-phenyldiazenylsalicydenaminato) nickel(II), copper(II) and zinc(II) complexes, and without azo-groups, bis(N-R-1-cyclohexylethyl-3,5-dichlorosalicydenaminato) nickel(II), copper(II) and zinc(II) complexes, affording a distorted square planar trans-[MN₂O₂] coordination geometry were prepared. Organic/inorganic hybrid materials in polymethylmethacrylate (PMMA) spincoat films of the complexes (both the azobenzene (AZ) containing type and the latter complexes of the AZ separated type) were assembled for a comparison of polarized UV light induced molecular arrangement caused by the Weigert effect. Investigation of the parameters for the optical anisotropy of the metal complexes as well as AZ suggested that the degree of increasing optical anisotropy of the containing type was higher than that of the separated type based on π-π^∗ (of which a characteristic band appeared around 380 nm) and n-π^∗ bands of polarized absorption electronic spectra. In the AZ containing type, the rigid nickel(II) or zinc(II) complexes easily increase the optical anisotropy compared to the flexible copper(II) complexes. In the AZ separated type, interestingly, enhancement of some CD bands suggests the role of chiral dopants of some complexes without azo-groups for AZ.     

Complexes of Co(II), Ni(II) and Cu(II) with lapachol

Complexes of naturally occurring hydroxynaphtho-quinone, lapachol (2-hydroxy-3(3-methyl-2-buthenyl)-1,4-naphthoquinone = HL) with Co(II), Ni(II) and Cu(II) have been prepared by reaction of the corresponding acetates with the ligand (HL) in ethanol. The molecular and crystal structures were determined for [CoL₂(EtOH)₂] (1), [NiL₂(EtOH)₂] (2), and [CuL₂(py)₂] (3). In all cases the deprotonated lapachol behaves as chelating bidentate ligand. The complexes were also characterized by elemental analyses, cyclic voltammetry, and FAB-MS.     

SYNTHESIS OF 1,2-DIHYDROXYIMINO-l-PHENYL-3,7-DIAZA-9,10-O-BENZALOCTANE AND ITS COMPLEXES WITH Co(II), Cu(II) AND Ni(II)

Abstract

A novel dioxime, 1,2 dihydroxyimino-3,7-diaza-9,10-O-benzaloctane (LH₂) was prepared by reaction of l,2-0-benzylidene-4-aza-7-aminoheptane and anti-phenylchloroglyoxime in absolute ethanol. Mononuclear complexes with a metal-ligand ratio of 1:2 were prepared with Co(II), Cu(II) and Ni(II). To elucidate the structures of the ligand and complexes, elemental analyses, IR, ¹H NMR and ¹³C NMR spectral data and magnetic susceptibility measurements have been examined.     

Synthesis and Characterization of A Vic-Dioxime Derivative and Investigation of its Complexes with Ni(II), Co(II), Cu(II) and UO2(VI) Metals

In this study, 1,2-dihdroxyimino-3,7-di-aza-9,10-O-iso-propylidene decane (LH₂ ) was synthesized starting from 1,2-O-iso-propylidene-4-aza-7-aminoheptane (RNH₂ ) and anti-chloroglyoxime. Complexes of this ligand with Ni(II), Co(II), Cu(II) and UO₂(VI) salts were prepared. Structures of the ligand and its complexes are proposed based on elemental analyses, IR, ¹³C and ¹H NMR spectra magnetic susceptibility measurements and thermogravimetric analyses (TGA).     

Studies on mononuclear chelates derived from substituted Schiff-base ligands (part 6): synthesis and characterization of a new 3-ethoxysalicyliden- p -aminoacetophenoneoxime and its complexes with cobalt(II), nickel(II), copper(II) and zinc(II)

Schiff-base complexes of cobalt(II), nickel(II), copper(II) and, zinc(II) with 3-ethoxysalicyliden-p-aminoacetophenoneoxime (HL) were prepared and characterized on the basis of elemental analyses, IR, ¹H- and ¹³C-NMR, electronic spectra, magnetic susceptibility measurements, molar conductivity and thermogravimetric analyses (TGA). A tetrahedral geometry has been assigned to the complexes.     

REPARATION AND CHARACTERIZATION OF NEW SUPROFEN COMPLEXES OF Fe(III), Co(II) AND Ni(II)

Abstract

The preparation and properties of new complexes containing the biometals Fe(III), Co(II) and Ni(II) coordinated to the anti-inflammatory drug Suprofen are reported. The elemental analyses, together with the magnetic and thermal behavior and electronic, IR and Raman spectra, indicated the following stoichiometries for the latter two complexes: [M(Sup)₂(H₂O)₄]. For the Fe(III) complex, the generation of a dinuclear species may be proposed on the basis of ⁵⁷Fe Mössbauer measurements.     

KINETICS OF FORMATION AND STABILITY CONSTANTS OF MONO AND BIS l-TYROSINE COMPLEXES OF Cu(II), Co(II), AND Ni(II)

Abstract

The kinetics and stability constants of l-tyrosine complexation with copper(II), cobalt(II) and nickel(II) have been studied in aqueous solution at 25° and ionic strength 0.1 M. The reactions are of the type M(HL)^(3-n)+ _n-1 + HL- ? M(HL)^(2-n)+_n(k_n, forward rate constant; k_-n, reverse rate constant); where M=Cu, Co or Ni, HL^? refers to the anionic form of the ligand in which the hydroxyl group is protonated, and n=1 or 2. The stability constants (K_n=k_n/k_-n) of the mono and bis complexes of Cu²⁺, Co²⁺ and Ni²⁺ with l-tyrosine, determined by potentiometric pH titration are: Cu²⁺, log K₁=7.90 ± 0.02, log K₂=7.27 ± 0.03; Co²⁺, log K₁=4.05 ± 0.02, log K₂=3.78 ± 0.04; Ni²⁺, log K₁=5.14 ± 0.02, log K₂=4.41 ± 0.01. Kinetic measurements were made using the temperature-jump relaxation technique. The rate constants are: Cu²⁺, k₁=(1.1 ± 0.1) × 10⁹ M ^?1 sec^?1, k_-1=(14 ± 3) sec^?1, k₂=(3.1 ± 0.6) × 10⁸ M ^?1 sec^?1, k^?2=(16 ± 4) sec^?1; Co²⁺, k₁=(1.3 ± 0.2) × 10⁶ M ^?1 sec^?1, k_-1=(1.1 ± 0.2) × 10² sec^?1, k₂=(1.5 ± 0.2) × 10⁶ M ^?1 sec^?1, k_-2=(2.5 ± 0.6) × 10² sec^?1; Ni²⁺, k₁=(1.4 ± 0.2) × 10⁴ M ^?1 sec^?1, k_-1=(0.10 ± 0.02) sec^?1, k₂=(2.4 ± 0.3) × 10⁴ M ^?1 sec^?1, k_-2=(0.94 ± 0.17) sec^?1. It is concluded that l-tyrosine substitution reactions are normal. The presence of the phenyl hydroxyl group in l-tyrosine has no primary detectable influence on the forward rate constant, while its influence on the reverse rate constant is partially attributed to substituent effects on the basicity of the amine terminus.     

Cu(II), Zn(II), AND Pb(II) STABILITY CONSTANTS OF CYCLAM AMPHIPHILES

Abstract

1-Hexadecyl-1,4,8,11-tetraazacyclotetradecane (hexadecyl cyclam) and 1-(3,7,11,15-tetramethyl) hexadecyl-1,4,8,11-tetraazacyclotetradecane (tetramethylhexadecyl cyclam) have been synthesized and their deprotonation and ligand-metal formation constants, K, determined for Cu(II), Zn(II) and Pb(II). The coupling of a long hydrocarbon chain to a ring nitrogen decreased the general ability of the cyclam ring to complex with metal ions. The greatest effect appeared to be for Cu(II) decreasing from a pK of 27 for cyclam to about 17. The titrations were fitted by HYPERQUAD and the concentrations of the intermediate complexes obtained as a function of pH. Metal-ligand complexes LMH₂ ⁴⁺, LMH₂₊ and LM₂₊ can coexist through a wide pH range. We have also calculated a composite metal-binding constant, K′, to reflect more accurately the overall ability of these ligands to bind a metal at any particular pH. K′, which is 14.6 for (hexadecyl cyclam)-Cu(II), is constructed from the concentrations of all the metal-chelated species at pH = 7. Generally, K′ is much lower than K.     

POTENTIOMETRIC,POLAROGRAPHIC AND SPECTROSCOPIC STUDIES OF THE Cu(II)-D-GLUCOSAMINE-D-LACTOBIONIC ACID TERNARY SYSTEMS

Abstract

Our recent work on Cu(II) and VO(IV) interactions with lactobionic acid have shown^1,2 that this sugar acid has an unusually high ability to coordinate both metal ions. The carboxyl group is not a very effective donor for cupric ions^3,4 and metal interations with the set of the protonated hydroxyl groups should have considerable effects on complex stability. This high stability of the lactobionic acid complexes can lead to the involvement of this ligand in formation of ternary complexes with ligands such as aminosugars.^3–6 Both ligands are important chelating agents for Cu(II) ions in medicine, agriculture and food chemistry.^7–9 Since ternary complexes may play an important role in natural systems we have decided to follow complex formation in solutions containing lactobionic acid and one an aminosugar, D-glucosamine. The anchoring group in D(+)-glucosamine (2-amino-2-deoxy-D-glucose) is an amino group which is much more effective donor than carboxylate which acts as an anchor in sugar acids. Thus in our study we have used excess lactobionic acid to promote the formation of ternary complexes as major species in the solutions studied.     

2-甲基-5-(2-吡啶基)-1,3,4-噁二唑Cu(II),Cd(II)配合物的合成,晶体结构和表征

以2-甲基-5-（2-吡啶基）-1,3,4-噁二唑（L）为配体合成了[Cu₂L₂（μ-Cl）₂Cl₂]（1）和[CdL₂（NO₃）₂]（2）,测定了X射线单晶结构,用红外光谱、紫外光谱、荧光及热重分析进行了表征。配体L和配合物2属于单斜晶系,配合物1属于三斜晶系。L,1和2的空间群分别为P2₁/c,P1和C2/c。配合物1是通过2个氯原子（Cl1,Cl1ⁱ）桥联形成的双桥双核Cu(II)配合物,具有畸变四方锥构型[CuCl₃N₂]。配合物2具有畸变八面体构型[CdN₄O₂]。     

CHROMOTROPIC CHANGES OF Cu(II) AND Ni(II) COMPLEXES WITH N2O2 AND N3O2 SCHIFF-BASE LIGANDS IN THE SOLID PHASE

Abstract

Four new Schiff-base ligands have been prepared from the condensation of 3-formyl-4-hy-droxy-1,8-naphthyridin-2-one with different diamines and a triamine, H₂L_a-H₂L_d. Two series of Ni(II) and Cu(II) complexes with the four ligands were also prepared. The ligands and their metal complexes were characterized by chemical analyses, IR, Far-IR, electronic, ESR and mass spectra as well as magnetic measurements and X-ray diffraction patterns.

Different products for Ni(II) and Cu(II) were obtained in similar reactions with the same metal salt, depending on the nature of the ligand. Different geometries were also obtained depending on the counter anion of metal salt. Thus, violet square-planar Cu(II) complexes were obtained with Cu(OAc)₂. H₂O and green octahedral ones with CuCl₂. 2H₂O, except the reaction with ligand H₂L_d which gave only an octahedral product whether the anion was acetate, chloride or perchlorate. Electronic and ESR spectra were used to differentiate between the two geometries of the Cu(II) complexes. The green octahedral Cu(II) complexes undergo irreversible thermochromism to the violet square-planar complexes except the copper complex of the ligand H₂L_d which did not not show any color change and retained its octahedral geometry. Based on the magnetic moments and thermal analyses, only one Ni(II) complex of the Schiffbase ligand H₂L_c undergoes reversible thermochromism from green (octahedral) to red (squareplanar). The reverse change of the thermal product (red) to the parent complex (green) proceeded on exposure to atmospheric air for a few minutes. On the other hand, Ni(II) complexes of ligands H₂L_a and H₂L_b have stable square-planar geometry and all efforts to add other ligands such as H₂O or pyridine to these complexes failed to yield other products. The corresponding Cu(II) complexes were easily transformed to their octahedral geometry by adding H₂O or pyridine and heating.     

Synthesis and X-ray crystallographic studies of Ni (II) and Cu (II) complexes of [5-(4-pyridyl)-1,3,4] oxadiazole-2-thione/thiol formed by transformation of N-(pyridine-4-carbonyl)-hydrazine carbodithioate in the presence of ethylenediamine

The reaction of [M(H₂L)₂] [M = Ni(II) Cu(II)] (K⁺H₂L⁻ = N-(pyridine-4-carbonyl)-hydrazine carbodithioate) with excess of ethylenediamine (en) gave mixed ligand complexes [Ni(en)₂(4-pytone)₂] (4-pytone = 5-(4-pyridyl)-1,3,4-oxadiazole-2-thione), and [Cu(en)₂](4-pytol)₂·H₂O (4-pytol = 5-(4-pyridyl)-1,3,4-oxadiazole-2-thiol). The metal complexes have been characterized with the aid of elemental analyses, IR, magnetic susceptibility and single crystal X-ray studies. Complexes (1) and (2) crystallize in monoclinic system, space group P_{1 21}/n₁ and C₂/c, respectively. The ligand after cyclization is present in the deprotonated thiol form in the Cu(II) complex where it is ionically bonded through sulfur. In the Ni(II) complex (1) bonding of the ligand take place through oxadiazole nitrogen and the ligand exists as the thione form.     

Thermal, spectral and magnetic characterization of Co(II), Ni(II) AND Cu(II) 4-chloro-2-nitrobenzoates

Physico-chemical properties of 4-chloro-2-nitrobenzoates of Co(II), Ni(II), and Cu(II) were studied. The complexes were obtained as mono- and trihydrates with a metal ion to ligand ratio of 1:2. All analysed 4-chloro-2-nitrobenzoates are polycrystalline compounds with colours depending on the central ions: pink for Co(II), green for Ni(II), and blue for Cu(II) complexes. Their thermal decomposition was studied only in the range of 293–523 K, because it was found that on heating in air above 523 K 4-chloro-2-nitrobenzoates decompose explosively. Hydrated complexes lose crystallization water molecules in one step and anhydrous compounds are formed. The final products of their decomposition are the oxides of the respective transition metals. From the results it appears that during dehydration process no transformation of nitro group to nitrite takes place. The solubilities of analysed complexes in water at 293 K are of the order of 10^–4–10^–2 mol dm^–3. The magnetic moment values of Co²⁺, Ni²⁺ and Cu²⁺ ions in 4-chloro-2-nitrobenzoates experimentally determined at 76–303 K change from 3.89 to 4.82 μ_B for Co(II) complex, from 2.25 to 2.98 μ_B for Ni(II) 4-chloro-2-nitrobenzoate, and from 0.27 to 1.44 μ_B for Cu(II) complex. 4-chloro-2-nitrobenzoates of Co(II), and Ni(II) follow the Curie–Weiss law. Complex of Cu(II) forms dimer.     

Synthesis,structural studies and bio-activity of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes with p -amino acetophenone salicyloyl hydrazone

Complexes of the type [M(pash)Cl] and [M(Hpash)(H₂O)SO₄] (M=Mn(II), Co(II), Ni(II), Cu(II) and Zn(II); Hpash = p-amino acetophenone salicyloyl hydrazone) have been synthesized and characterized by elemental analyses, molar electrical conductance, magnetic moments, electronic, ESR and IR spectra, thermal studies and X-ray powder diffraction. All the complexes are insoluble in common organic solvents and are non-electrolytes. The magnetic moment values and electronic spectra indicate a square-planar geometry for Co(II), Ni(II) and Cu(II) chloride complexes and spin-free octahedral geometry for the sulfato complexes. The ligand coordinates through >C=N–,–NH₂ and a deprotonated enolate group in all the chloro complexes, and through >C=N–, >C=O and–NH₂ in the sulfato complexes. Thermal analyses (TGA and DTA) of [Cu(pash)Cl] show a multi-step exothermic decomposition pattern. ESR spectral parameters of Cu(II) complexes in solid state at room temperature suggest the presence of the unpaired electron in d _{x ² ? y ²} . X-ray powder diffraction parameters for [Cu(pash)Cl] and [Ni(Hpash)(H₂O)SO₄] correspond to tetragonal and orthorhombic crystal lattices, respectively. The complexes show a fair degree of antifungal activity against Aspergillus sp., Stemphylium sp. and Trichoderma sp. and moderate antibacterial activity against E. coli and Clostridium sp.     

THE INTERACTION OF 2-AMINO-2-HYDROXYMETHYL-1,3-PROPANEDIOL WITH COBALT(II) AND MANGANESE(II) IONS

Abstract

The stepwise complex formation between 2-amino-2-hydroxymethyl-1,3-propanediol (TRIS) with Co(II) and Mn(II) was studied by potentiometry at constant ionic strength 2.0 M (NaClO₄) and T = (25.0 ± 0.1)°C, from pH measurements. Data of average ligand number (Bjerrum's function) were obtained from such measurements followed by integration to obtain Leden's function, F ₀(L). Graphical treatment and matrix solution of simultaneous equations have shown two overall stability constants of mononuclear stepwise complexes for the Mn(II)/TRIS system (β₁ = (5.04 ± 0.02) M^?1 and β₂ = (5.4 ± 0.5) M^?2) and three for the Co(II)/TRIS system (β₁ = (1.67 ± 0.02) × 10² M^?1, β₂ = (7.01 ± 0.05) × 10³ M^?2 and β₃ = (2.4 ± 0.4) × 10⁴ M^?3). Slow spontaneous oxidation of Co(II) solutions by dissolved oxygen, accelerated by S(IV), occurs in a buffer solution TRIS/HTRIS⁺ 0.010/0.030 M, with a synergistic effect of Mn(II).