Metallothionein Induction by Cd(II) and Zn(II)

Blood may contain high proportion of the toxic and essential metals.Blood is responsiblefor the transport of ion of such metals.The organs such as the kidney,liver and placentaare exposed to a large proportion of the metals which enter the blood and may b…     

The Thermal Analysis of Binary Zn(II)–Sr(II) Cyclo-tetraphosphates

Binary Zn(II)–Sr(II) cyclo-tetraphosphates have been synthesised as new binary compounds. The synthesis is based on a thermal procedure making use of the reversible transformation of cyclo- tetraphosphates to higher linear phosphates. With respect to the proposed application of these products as special inorganic pigments some properties (thermal stability, structural parameters, anticorrosion activity) have been determined. This revised version was published online in August 2006 with corrections to the Cover Date.     

Ion-Exchange Processes M(II) → Fe(III) and Fe(III) → M(II) in Metal Hexacyanoferrate(II) Gelatin-Immobilized Matrices (M = Mn,Co, Ni,Cu, Zn,Cd)

Ion-exchange reactions M²⁺ Fe³⁺ and Fe³⁺ M²⁺ (M = Mn, Co, Ni, Cu, Zn, Cd) were studied in metal(II) hexacyanoferrate(II) gelatin-immobilized matrices M₂[Fe(CN)₆] in contact with aqueous FeCl₃ solutions and Fe₄[Fe(CN)₆]₃ in contact with aqueous MCl₂ solutions. It was shown that in both cases, M²⁺ was replaced by Fe³⁺ and Fe³⁺ was replaced by M²⁺ to some extent, but no complete replacement was observed in the M₂[Fe(CN)₆]–FeCl₃ or Fe₄[Fe(CN)₆]₃–MCl₂ systems under study. No electrophilic substitution Fe³⁺ Mn²⁺ was found to occur in any noticeable degree during the contact of Fe₄[Fe(CN)₆]₃ with aqueous MnCl₂ solutions even when this contact occurred for 1 h and longer.     

Coordination reactions of 3,3′-bis(dipyrrolylmethene) with Co(II), Cu(II), and Zn(II) acetylacetonates, valinates, and dipyrrolylmethenates

Using spectrophotometry we found that ligand exchange in the systems of H₂L-[MX₂]-DMF, where M denotes Co²⁺, Cu²⁺, and Zn²⁺; X means Acac^?, Val^?, dpm^?; Hdpm^? is hexamethyldipyrrolylmethene, H₂L is bis(2,4,7,8,9-pentamethyldipyrrolylmethene-3-yl)methane, proceeds through successive stages of formation of hetero- and homoleptic binuclear complexes. Conventional sensitivity of the spectrophotometric determination of Co²⁺, Cu²⁺, and Zn²⁺ reaches 10^?9 M.     

Crystal Structures and Characterizations of Bis(pyrrolidinedithiocarbamato) Cu(II) and Zn(II) Complexes

ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅａｂｉｌｉｔｙｏｆｄｉｔｈｉｏｃａｒｂａｍａｔｅ(ｄｔｃ)ｂｉｎｄｉｎｇｔｏｍｅｔａｌｓｈａｓｂｅｅｎｋｎｏｗｎｆｏｒｍａｎｙｙｅａｒｓ .Ｉｔｆｏｒｍｓｃｈｅｌａｔｅｓｗｉｔｈｖｉｒｔｕ ａｌｌｙａｌｌｔｒａｎｓｉｔｉｏｎｍｅｔａｌｓ.1Ｔｈｅｂｉｄｅｎｔａｔｅａｎｉｏｎｉｓａｌｓｏｗｅｌｌｋｎｏｗｎａｓａｂｒｉｄｇｅｂｅｔｗｅｅｎｔｗｏｔｒａｎｓｉｔｉｏｎｍｅｔａｌｃｅｎｔｅｒｓ.2 Ｗａ ｔｅｒ ｓｏｌｕｂｌｅｄｉａｌｋｙｌｄｉｔｈｉｏｃａｒｂａｍａｔｅｃｏｍｐｌｅｘｅｓ…     

A Zn(II) 5-Aminoisophthalate Coordination Polymer

The title compound, [Zn(AIP)(4,4-bipy)0.5(H2O)]n·0.75nH2O 1, was synthesized via the hydrothermal reaction of Zn(OAc)2 with 5-aminoisophthalic acid (H2AIP) and characterized by elemental analysis and infrared spectra. The complex crystallizes in monoclinic system, space group P21/c with a = 12.672(1), b = 7.6557(4), c = 16.181(1) , β = 109.187(2)o, V = 1482.6(2) 3, Z = 1, C52H52N8O23Zn4, Mr = 1418.58, Dc = 1.589 g/cm3, F(000) = 724 and μ(MoKα) = 1.685mm-1. The final R = 0.0702 and wR = 0.1524 for 1847 observed reflections with I > 2σ(I), and R = 0.0873 and wR = 0.1664 for all data. X-ray diffraction studies reveal that the title compound has an interesting 2D microporous architecture with guest water molecules inside the channel.     

Synthesis and characterisation of Co(II), Ni(II), Zn(II) and Cd(II) complexes with 5-bromo-N,N′-bis-(salicylidene)-o-tolidine

New complexes of type [M(HL)(CH₃COO)(OH₂)_m]·nH₂O (where M:Co, m = 2, n = 2; M:Ni, m = 2, n = 1.5; M:Zn, m = 0, n = 2.5 and M:Cd, m = 0, n = 0; H₂L:5-bromo-N,N′-bis-(salicylidene)-o-tolidine) have been synthesized and characterized by microanalytical, IR, UV–Vis-NIR and magnetic data. Electronic spectra of Co(II) and Ni(II) complexes are characteristic for an octahedral stereochemistry. The IR spectra indicate a chelate coordination mode for mono-deprotonated Schiff base and a bidentate one for acetate ion. The thermal transformations are complex according to TG and DTA curves including dehydration, acetate decomposition and oxidative degradation of the Schiff base. The final product of decomposition is the most stable metallic oxide.     

Effect of alkyl group on the structure of heterodinuclear Zn(II)–Cu(II) and Zn(II)–Ni(II) complexes derived from unsymmetrical phenol-based dicompartmental macro-acyclic ligands

A series of mono- and heterodinuclear macro-acyclic complexes of [ZnLCu(II)]²⁺ and [ZnLNi(II)]²⁺ were synthesized by a stepwise procedure. The phenol-based macro-acyclic dicompartmental ligands (L^2?) possess contagious hexadentate (N₄O₂) and tetradentate (N₂O₂) coordination sites, where in the mononuclear complexes [ZnL(H⁺)₂]²⁺ the latter site containing two alkyl-imine donor groups (ethyl or isopropyl) is attached to the azomethine moieties. The alkyl group(s) is eliminated upon introduction of the second metal (II) ion into N₂O₂ coordination site as a result of steric crowding of the alkyl groups along with the lack of flexibility associated with the imine groups. When the second metal ion is Cu(II) and R = isopropyl, the both of them are eliminated but when R = Et only one ethyl group is removed. However, in case of Ni(II) as the second metal ion, the both alkyl groups are eliminated regardless of the nature of the alkyl group. The origins of the structural variations are discussed. The prepared complexes were characterized by elemental analysis, molar conductance measurements, X-ray crystallography, IR, NMR and UV–Vis spectroscopies.     

Synthesis,crystal structures,and properties of two heterometallic Cu(II)–M(II) (M = Zn,Ni) oxamidato-bridged coordination complexes

Two heterometallic coordination complexes, {[Cu(aeop)Zn(H₂O)₃]₂?·?3H₂O} _n (1) and [Cu(aeop)Ni(H₂O)₄]?·?4H₂O (2) (H₄aeop?=?N-(2-aminoterephthalic acid)-N′-(1,3-propanediamine)oxamidate), have been synthesized and characterized by elemental analyses, IR, UV spectroscopy, thermogravimetric analysis, and X-ray crystal diffraction. Complex 1 features a 1-D chain constructed from neutral tetranuclear units. Complex 2 is a neutral binuclear complex. Through intermolecular hydrogen-bonding interactions, 2 gives a 3-D network structure. The variable temperature magnetic susceptibility measurements (2–300?K) of 2 show a pronounced antiferromagnetic interaction between the copper(II) and nickel(II), and the exchange integral J is equal to ?42.7?cm^?1.     

Interaction of Co(II), Ni(II), Cu(II), and Zn(II) with N,N′-(aldose)2-thiocarbohydrazide: synthesis,electrochemistry, and spectral characterization

Complexes of Co(II), Ni(II), Cu(II), and Zn(II) with N,N′-(aldose)₂–thiocarbohydrazide (LH₂) were synthesized, isolated as solid products and characterized by analytical means as well as by spectral techniques, FTIR, ¹H NMR, EPR, UV spectroscopy, and CD. All the metal ions formed M[LH]X complexes. Molar conductance values in DMF indicate non-electrolytic complexes. In DMSO with tetramethylammonium chloride supporting electrolyte, the copper complex displays irreversible cyclic voltammetric responses with E _p near ?0.621 and 0.461 V versus Ag/AgCl at scan rate of 0.1 V s^?1. Probable structures for the complexes are proposed.     

Trinuclear Cu(II) and Zn(II) complexes bridged by μ3-carbonato anion

The trinuclear Cu(II) and Zn(II) complexes [(CuTPA),(μ₃-CO,)] (C10₄)₄(1) and [(ZnTPA),(μ₃-C0₃)](C10₄)₄ (2) (TPA = tri(pyridylmethy1)amine) have been synthesized. X-ray structure analysis of the two complexes proves that CO₃ ^2- anion has an unusual triply bridging ligand, bridging three CuTPA and ZnTPA units respectively, and assembles new trinuclear complexes. The CO₃ ²- comes from atmospheric CO₂. The structure of each trinuclear unit consists of three copper or zinc atoms in a five-coordinate triangular hipyramidal environment. The [(CuTPA)₃(μ₃-C0₃) ](C10₄), compound shows a very weak antifemmagnetic coupling. Project supported by the National Natural Science Foundation of China (Grant No.29771021).     

Synthesis,characterization, spectral studies and antifungal activity of Mn(II), Fe(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes with 3,3′-bis[N,N,di(carboxymethyl)-aminomethyl]- o -cresol sulphonphthalein

Mn(II), Fe(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes of the type Na₄[ML(H₂O)₂] of the ligand, 3,3′-bis[N,N-di(carboxymethyl)-aminomethyl]-o-cresol sulphonphthalein (Xylenol Orange, Na₄H₂L), have been synthesized and characterized by different physico-chemical (elemental analyses, solubility, electrolytic conductances, magnetic susceptibility measurements) and spectral (u.v.-vis, i.r., e.s.r., and powder X-ray diffraction) techniques for their structure determination. The data suggest 1?:?1 (M?:?L) compositions and octahedral geometries around M(II) except for Cu(II). Antifungal activity of the complexes measured against ten fungi show significant activity against Alternaria brassicicola, Alternaria solanai, Cercospora species and Helminthosporium oryzae and moderate antifungal activity against Curvularia species, Curvularia lunata, Curvularia penniseti, Colletotrichum capsici, Aspergillus niger, Aspergillus flavus Erysiphae pisi and Fusarium udum fungi.     

Electrophilic Substitution Mn(II) → M(II) (M = Co,Ni, Cu,Zn, Cd) in Gelatin-Immobilized Mn2[Fe(CN)6]

Reactions of electrophilic substitution Mn(II) M(II) (M = Co, Ni, Cu, Zn, Cd) are studied in gelatin-immobilized Mn(II) hexacyanoferrate(II) systems brought in contact with aqueous solutions of metal chlorides MCl₂. As the result of this contact, Mn(II) is replaced by Co(II), Ni(II), Cu(II), Zn(II), or Cd(II) to give heteronuclear metal hexacyanoferrates(II) (MHCF) of Mn(II) and two-charged ions. Neither of the systems under study showed a complete substitution of Mn(II) or the formation of the respective mononuclear hexacyanoferrate(II) M₂[Fe(CN)₆]. When any of the above gelatin-immobilized MHCF was brought in contact with an aqueous solution of MnCl₂, no electrophilic substitution M(II) Mn(II) was observed even for a long contact time.     

Stimuli-responsive,thixotropic bicomponent hydrogel of melamine–Zn(II)-orotate complex

Zinc(II)-orotate complex (ZnOA) has been synthesised, and it is used to produce supramolecular complex with melamine (M) at 1:1 molar ratio. During sonication for 5–6 min, the supramolecular complex is transformed into a bi-component hydrogel (S-gel). The spectroscopic tools such as FTIR and UV–vis spectra suggest that the H-bonding interaction between M and ZnOA produces a supramolecular complex which further forms J-aggregates during gelation. The circular dichroism spectra indicate the change in ellipticity with temperature that arises from the molecular dissymmetry during stacking of the ZnOAM complexes. The microscopic images indicate that the hydrogel network is formed with short helical nano-fibres. The energy-minimised structure of ZnOAM complex exhibits a well-defined d value of 11.3 Å obtained from X-ray scattering of the xerogel. The frequency-dependent rheological experiment (storage modulus (G′) is greater than loss modulus (G″)) characterises it as a gel. The gel shows thixotropic and stimuli-responsive behaviour.     

Ring-opening polymerization of ε-caprolactone catalysed by (pyridyl)benzoazole Zn(II) and Cu(II) complexes

This paper describes the synthesis of (pyridyl)benzoazole Zn(II) and Cu(II) complexes and their applications as catalysts in ring-opening polymerization (ROP) of ε-caprolactone (ε-CL). Reactions of 2-(3-pyridyl)-1H-benzimidazole (L1), 2-(2-pyridyl)-1H-benzothiazole (L2) and 2-(2-pyridyl)-1H-benzimidazole (L3) with Zn(II) and Cu(II) acetates produced the corresponding complexes; [Zn₂(L1)₂(OAc)₄)] (1), [Cu₂(L1)₂(OAc)₄] (2), [Zn(L2)(OAc)₂)] (3), [Zn(L3)(OAc)₂)] (4) and [Cu(L3), (OAc)₂)] (5). Molecular structures of complexes 2 and 5a revealed that while L1 adopts a monodentate binding mode, through the pyridyl nitrogen atom, L3 exhibits a bidentate coordination mode. All the complexes formed active catalysts in the ROP of ε-CL to afford moderate molecular weight polymers. The kinetics of the ROP reactions of ε-CL were pseudo-first-order with respect to monomer and catalysts.     

Redox reactions of peroxo terpyridine complexes of Cu(II), Zn(II), and Cu(II)?Zn(II): A pulse radiolysis study

The reactions of e_aq⁻, CH₂OH·, (CH₃)₂COH·, CO, OH· and N₃· radicals with peroxo terpyridine complexes of Cu(II), Zn(II), and Cu(II) Zn(II) in aqueous solution were investigated by pulse radiolysis. The primary products from the reduction and oxidation of the macrocyclic complexes were assigned a radical nature by comparing their optical spectra with those of Cu(I), Zn(I), and Cu(III) species. Such metal–ligand radical products undergo disproportionation that does not lead to the formation of Cu(0) or colloidal copper. © 2000 John Wiley & Sons, Inc. Int J Chem Kinet 32: 92–98, 2000     

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.     

Electrophilic Substitution Co(II)→M(II) (M = Mn,Ni, Cu,Zn, Cd) in Co2[Fe(CN)6] Gelatin-Immobilized Matrices

Electrophilic substitutions Co(II) M(II) (M = Mn, Ni, Cu, Zn, Cd) in cobalt(II) hexacyanoferrate(II) gelatin-immobilized matrices in contact with aqueous solutions of corresponding chlorides MCl₂ were studied. As a result of this contact, Co(II) was shown to be replaced to some extent by Ni(II), Cu(II), Zn(II), or Cd(II) and to give heteronuclear cobalt(II) hexacyanoferrates(II) and two-charge ions. A complete substitution of Co(II) or the formation the respective mononuclear hexacyanoferrate(II) M₂[Fe(CN)₂] was observed in neither of the studied systems Co(II) M(II). No Co(II) Mn(II) substitution was observed, even though the immobilized matrix was in contact with a solution for a long time.     

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.     

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.