Antimicrobial activity of aniline‐formaldehyde resin modified by adding piperazine moiety and its metal polychelates

Aniline‐formaldehyde resin modified by adding piperazine (AFP) was prepared in alkaline medium, and its metal polychelates have also been prepared with Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) metal ions. The synthesized compounds were characterized by elemental, spectral (UV–Vis, IR, ¹H‐NMR and ¹³C‐NMR), thermogravimetric analysis (TGA), and magnetic moment measurements. The percentage of metal in all of the polychelates was found to be consistent with 1:1 (metal/resin) stoichiometry. The thermal behaviors of these coordination polymers were studied by TGA in a nitrogen atmosphere up to 750°C. The TGA results revealed that all the metal polychelates had higher thermal‐resistance property compared to the common resin (AFP). The magnetic moment measurements and UV–Vis spectra confirmed the geometry of the central metal ion in all the polychelates. All the synthesized metal polychelates showed excellent antibacterial activities against the selected bacteria. The antibacterial activities were determined using the shaking flask method, where 25 mg/ml concentrations of each compound were tested against 10⁵ CFU/ml bacteria solutions. The number of viable bacteria was calculated by using the spread plate method, where 100 µl of the incubated antibacterial agent in bacteria solutions was spread on agar plates, and the number of bacteria was counted after 24 hr of incubation period at 37°C. Copyright © 2008 John Wiley & Sons, Ltd.     

Synthesis,spectral, and antibacterial screening studies of chelating polymers of bisphenol-A–formaldehyde resin bearing barbituric acid

A new polymeric ligand was synthesized by the reaction of bisphenol-A and formaldehyde in the basic medium, followed by condensation polymerization with barbituric acid in the acidic medium. Polymer metal complexes were prepared by reaction of this resin with Mn(II), Co(II), Ni(II), Cu(II), and Zn(II). The polymeric resin and its metal polychelates were characterized by elemental analysis, FT-IR, ¹³C-NMR, and ¹H-NMR spectra. The geometry of the polymer metal complexes was evaluated by electronic spectra (UV-Vis) and magnetic moment measurement. Thermal stabilities show an increased thermal stability of the metal polychelates compared to the ligand. The antibacterial activities of all the synthesized polymers were investigated against Bacillus subtilis, Staphylococcus aureus, and Escherichia coli, showing good antibacterial activities against these bacteria. Cu(II) polychelate showed highest biocidal activity.     

Synthesis, Thermal, Electrical and Catalytic Studies of Some Transition Metal Polychelates of Bis-bidentate Schiff Base

Polychelates of Mn（Ⅱ）, Fe（Ⅱ）, Co（Ⅱ）, Ni（Ⅱ）, Cu（Ⅱ）, Zn（Ⅱ） and Cd（Ⅱ） with the bis salen-type ligand derived from 4,4＇-bis[（salicylaldehyde-5）azo]biphenyl and 1,4-diaminobutane have been synthesized. All the polychelalls have been characllrized by elemental analysis, magnetic susceptibility measurements, IR, electronic spectra and thennogravirncuic studies. All the complexes isolated in solid stall are dark coloured and insoluble in water and common organic solvents. The ligand behaves as a bis-bidentall molecule coordinating through the phenolic oxygen and azomethine nitrogen atoms. The thermal decomposition of these metal complexes was investigated by thermogravimetric analysis and data have been analyzed for kinetic parameters using Broido equation. The solid-state electrical conductivity of the ligand and its polychelalls in the form of compressed pellet was studied in the temperaturc range from 313 to 413 K All the polychelalls were found to show semiconducting nature. The Mn（Ⅱ）, Fe（Ⅱ）, Co（Ⅱ） and Ni（Ⅱ） polychelalls have been assessed for the catalytic epoxidation of styrene.     

Synthesis,characterization and anti-microbial studies of a newly developed polymeric Schiff base and its metal-polychelates

A new polymeric Schiff base containing formaldehyde and piperazine moieties has been synthesized by condensation of salicylaldimine, formaldehyde and piperazine in alkaline medium; its metal polychelates have also been synthesized with Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) acetate. The synthesized Schiff base and its metal polychelates were characterized by elemental, spectral (IR, ¹H NMR, UV-visible) and thermogravimetric analysis (TGA). Electronic spectra and magnetic moments indicate that Mn(II), Co(II) and Ni(II) polychelates show octahedral geometry, while Cu(II) and Zn(II) polychelates show square planar and tetrahedral geometry, respectively. All compounds show excellent anti-bacterial as well as anti-fungal activity against three bacteria and two fungi. The anti-microbial activities were determined by using agar well diffusion method, with 50 µg mL^?1 and 100 µg mL^?1 concentration of each compound tested against the microbes.     

Synthesis, magnetic, spectral, and antimicrobial studies of Cu(II), Ni(II) Co(II), Fe(III), and UO2(II) complexes of a new Schiff base hydrazone derived from 7-chloro-4-hydrazinoquinoline

A new hydrazone ligand, HL, was prepared by the reaction of 7-chloro-4-hydrazinoquinoline with o-hydroxybenzaldehyde. The ligand behaves as monoprotic bidentate. This was accounted for as the ligand contains a phenolic group and its hydrogen atom is reluctant to be replaced by a metal ion. The ligand reacted with Cu(II), Ni(II), Co(II), Fe(III), and UO2(II) ions to yield mononuclear complexes. In the case of Fe(III) ion two complexes, mono- and binuclear complexes, were obtained in the absence and presence of LiOH, respectively. Also, mixed ligand complexes were obtained from the reaction of the metal cations Cu(II), Ni(II) and Fe(III) with the ligand (HL) and 8-hydroxyquinoline (8-OHqu) in the presence of LiOH, in the molar ratio 1:1:1:1. It is clear that 8-OHqu behaves as monoprotic bidentate ligand in such mixed ligand complexes. The ligand, HL, and its metal complexes were characterized by elemental analyses, IR, UV-vis, mass, and 1H NMR spectra, as well as magnetic moment, conductance measurements, and thermal analyses. All complexes have octahedral configurations except Cu(II) complex which has an extra square-planar geometry, while Ni(II) mixed complex has also formed a tetrahedral configuration and UO2(II) complex which formed a favorable pentagonal biprymidial geometry. Magnetic moment of the binuclear Fe(III) complex is quite low compared to calculated value for two iron ions complex and thus shows antiferromagnetic interactions between the two adjacent ferric ions. The HL and metal complexes were tested against one stain Gram positive bacteria (Staphylococcus aureus), Gram negative bacteria (Escherichia coli), and fungi (Candida albicans). The tested compounds exhibited higher antibacterial acivities.     

Synthesis and spectroscopic studies of homo-binuclear, alkoxo bridged homo- and hetero-tetranuclear metal complexes of a bis-N2O4 Schiff base ligand derived from ethanolamine and macroacyclic tetranaphthaldehyde

Three new homo-binuclear Ni(II), Cu(II), Zn(II) complexes (2-4), homo-tetranuclear Cu(II) complex (5), and hetero-tetranuclear Cu(II)-Ni(II) complex (6) of a macroacyclic potentially bis-hexadentate N2O4 Schiff base have been synthesized. The imino-alcohol ligand, H4L was obtained by the condensation of ethanolamine with 2,2'-[2,3-bis(1-formyl-2-naphthyloxymethyl)-but-2-ene-1,4-diyldioxy]bis(naphthalene-1-carbaldehyde). The structures of both the Schiff base and its complexes have been proposed by elemental analyses, spectroscopic data i.e. IR, 1H and 13C NMR, UV-vis, electrospray ionisation mass spectra, molar conductivities and magnetic susceptibility measurements. The ligand has two similar compartments to bind first primary two metal ions, and acts bi- or tetra-negative, bis-tetradentate forming five membered chelate ring. However, secondary two metal ions (either Cu2+ or Ni2+) are ligated with dianionic oxygen atoms of the alcohol groups and are linked to the 1,10-phenanthroline-nitrogen atoms in the tetranuclear complexes (5 and 6).     

Bioactivity of some divalent M(II) complexes of penicillin based Schiff base ligand: Synthesis,spectroscopic characterization,and thermal study

A series of four novel metal complexes of Co(II), Ni(II), Cu(II) and Zn(II) were synthesized from Schiff base derived from amoxicillin (AMX) and picolinaldehyde (PC2). The ligand and metal complexes were fully characterized by physical and spectral techniques such as elemental microanalysis, conductivity, FT-IR, ¹H & ¹³C NMR, UV–vis, mass spectra, EPR, magnetic moment measurement, TGA/DTA, PXRD and antibacterial activity study. The spectroscopic study revealed 1:2 metal ligand ratio and coordination sites in the ligand for metal ions were evaluated by analysis of the spectral results. The surface morphology of the complexes was evaluated by SEM analysis. Molar conductivity implies non-electrolytic nature of the complexes. UV–vis. spectral study nicely supports octahedral geometry for Co(II) and Zn(II) complexes and tetrahedral geometry for Cu(II) complex. The kinetic parameters were extracted from Coats-Redfern equation. The PXRD study revealed nano-crystalline nature of Co(II), Ni(II) & Cu(II) complexes and amorphous nature of Zn(II) complex. The proposed geometry of the complexes was optimized by MM2 calculation supported in Cs-ChemOffice Ultra-11 program. The ligand and metal complexes were screened for antibacterial potency against four human pathogenic clinical strains of bacteria and the data revealed their promising antibacterial activity.     

基于香豆素Schiff碱双核Ni（Ⅱ）和立方烷型Cu4（μ3-O）4的四核Cu（Ⅱ）配合物的合成、晶体结构及光谱性质（英文）

合成了2个3-氨基-4-羟基香豆素类Schiff碱双核Ni?髤和立方烷型Cu4(μ3-O)4的四核Cu?髤配合物,[Ni(L1)(DMF)(H2O)]2(1)(H2L1=3-((5-溴-2-羟基-亚苄基)-氨基)-4-羟基-苯并吡喃-2-酮)和[Cu4(L2)4]·DMF·CH3OH·2H2O(2)(H2L2=4-羟基-3-((2-羟基-3-甲氧基-亚苄基)-氨基)-苯并吡喃-2-酮),并通过元素分析、红外光谱、紫外光谱、荧光光谱及X射线单晶衍射分析等手段进行了表征。X射线单晶衍射分析结果表明:配合物1具有双核结构,由2个金属离子和2个配体单元组成,配合物2具有立方烷型Cu4(μ3-O)4的四核结构,由4个金属离子和4个配体单元组成。配合物1是单斜晶系、C2/c空间群;配合物2是四方晶系,I41/a空间群,且中心金属Ni?髤和Cu?髤离子的空间构型均为六配位的扭曲的八面体。此外,配合物1通过分子间氢键、C-H…π及π…π作用形成1D超分子链结构,配合物2通过分子内氢键和π…π作用形成3D超分子结构。此外,研究了H2L1,H2L2及其相应的Ni?髤和Cu?髤配合物的荧光性质。     

Synthesis and studies on metal coordination with a novel carboxyamide ligand

Novel complexes of Co(II), Ni(II), Cu(II) and Pd(II) with the new ligand [N,N'-bis(2-carboxy-1-oxo-phenelenyl)ethylenediamine] (H2L) have been synthesized and characterized on the basis of elemental analyses, magnetic susceptibility, thermal, infrared, electronic, 1H NMR and EPR spectral studies. Infrared and 1H NMR spectra show that H2L acts as a binegative tetradentate ligand. Coordination occurs through deprotonated carboxylate oxygens and nondeprotonated amido nitrogens in all the complexes. Electronic spectral studies and magnetic moment values suggest N2O2 coordination around each metal centre with strong field square planar chromophores. The probable structures of the complexes have been assigned on the basis of spectral studies. The complex formation between M(II) [M(II) = Mn(II), Co(II), Ni(II), Cu(II) and Zn(II)] and (L2-) has also been studied potentiometrically in 75% aqueous DMF at 25 degrees C in 0.1 M NaClO4. The stability constants were found to follow the order: Mn(II) < Co(II) < Ni(II) < Cu(II) > Zn(II).     

Novel polymeric chelates of 8-hydroxyquinoline-dimethylolacetone

A new chelating copolymer (HQDMA) has been synthesized through copolymerization of 8-hydroxyquinoline and dimethylolacetone monomers in the presence of base as a catalyst. This newly developed copolymer ligand (H₂L) has been used to prepare a series of five polymeric chelates (ML) by using Zn(II), Cu(II), Ni(II), Co(II) and Mn(II) metal ions. Both the parent ligand and its metal chelates have been systemically investigated in detail to elucidate the chemical structure and thermal behaviour by elemental analyses, spectral (IR and electronic) characterization, number-average molecular mass determination and thermogravimetric analysis (TG). In addition to these, magnetic susceptibility measurements have also been carried out for studying geometry and metal-ligand stoichiometry of polymeric chelates. The chemical structure of polychelates on the basis of elemental and IR characterization suggests that the bidentate ligand (H₂L) coordinates to metal ions through oxygen atom of the phenolic hydroxyl group by replacing hydrogen atom and nitrogen of the quinoline ring. The studies of magnetic moments and electronic spectra reveal that all polychelates with octahedral geometry are paramagnetic in nature except that of Zn(II) chelate, which is diamagnetic. The thermogravimetric analysis of parent ligand and its metal chelates have shown remarkable difference in mode of thermal decomposition and their thermal stabilities. The kinetic parameter, energy of activation (E _a) of thermal decomposition has also been estimated by Broido method.     

Synthesis,spectral and thermal properties of poly(2-hydroxy-4-methacryloyloxybenzaldehyde)-metal complexes

2-Hydroxy-4-methacryloyloxybenzaldehyde (2H4MBA), prepared from methacryloyl chloride and 2,4-dihydroxybenzaldehyde, was polymerized in methyl ethyl ketone at 70°C using benzoyl peroxide as a free radical initiator. Polychelates were obtained from N,N-dimethylformamide solutions of poly(2H4MBA) on addition of aqueous solutions of Cu(II)/Ni(II) ions. The polymers and polychelates were characterized by elemental analyses and spectral studies. The IR spectra of these polychelates suggest that metals are coordinated through the oxygen of the aldehyde group and oxygen of the phenolic—OH group. The electronic spectra, EPR, and magnetic moments of polychelates showed an octahedral and square planar structure for poly(2H4MBA)-Ni(II) and poly(2H4MBA)-Cu(II) complexes, respectively. X-ray diffraction studies reveal that the polychelates are highly crystalline. The thermal properties of polymer-metal complexes and their catalytic activity are discussed. © 1996 John Wiley & Sons, Inc.     

Synthesis,crystal structure,magnetic and spectroscopic properties of {[Cu(oxbe)(py)]2Ni(py)2}·2Dmf complex of dissymmetrical oxamidate

The trinuclear complex {[Cu(oxbe)(py)]₂Ni(py)₂}·2DMF has been prepared and characterized by elemental analysis, IR and electronic spectra and magnetic susceptibility, where H₃oxbe is the dissymmetrical ligand N-benzoato-N′-(2-aminoethyl) oxamido, py?=?pyridine, DMF?=?dimethylformamide. The molecular structure of this complex is centrosymmetrical and has an extended oxamido-bridged structure consisting of two pyramidal copper(II) and one octahedral nickel(II) ions. The central Ni(II) and two terminal Cu(II) ions are antiferromagnetically coupled, J?=???60.2?cm^?1.     

Synthesis and characterization of azo sulfaguanidine complexes and their application for corrosion inhibition of silicate glass

A new azo dye ligand of sulfaguanidine with 5‐nitro‐8‐hydroxyquinoline and its Mn(II), Ni(II), Co(II) and Cu(II) complexes were synthesized and characterized using elemental analysis, inductively coupled plasma, molar conductance, X‐ray powder diffraction, thermogravimetric analysis, magnetic moment measurements, and infrared, ¹H NMR, electron impact mass and UV–visible spectral studies. The spectral studies and analytical data revealed that the azo dye ligand acts as a monobasic bidentate ligand via deprotonated OH and nitrogen atom of the azo group. The data support the mononuclear formulation of all complexes, except Cu(II) complex that has a binuclear formulation with a 1:2 metal to ligand ratio. The complexes have tetrahedral structure except Ni(II) which has octahedral geometry. The molar conductance data reveal that all the metal complexes are non‐electrolytic in nature The average particle size of the ligand and its Mn(II), Ni(II), Co(II) and Cu(II) complexes is 0.12–0.91 nm. The effect of these compounds for improvement of chemical durability of silicate glass in 0.1 M HCl was studied. Window and soda‐lime silica glass were taken as samples for the durability experiments. The inhibition efficiency of the ligand and its complexes for corrosion of glass surfaces after dissolution experiments was evaluated quantitatively using the specific weight loss method and qualitatively using scanning electron microscopy. The inhibition efficiencies of the tested compounds follow the order Co(II) complex > Mn(II) complex > Ni(II) complex > H₃L > Cu(II) complex. The chemical durability improvement is 88.12–56.25% and 87.99–51.96% for window and soda‐lime silica glass, respectively. Copyright © 2016 John Wiley & Sons, Ltd.     

Ni(II), Cu(II), and Zn(II) dinuclear metal complexes with an aza-phenolic ligand: crystal structures,magnetic properties,and solution studies

The basicity behavior and ligational properties of the ligand 2-((bis(aminoethyl)amino)methyl)phenol (L) toward Ni(II), Cu(II), and Zn(II) ions were studied by means of potentiometric measurements in aqueous solution (298.1 +/- 0.1 K, l = 0.15 mol dm-3). The anionic L-H- species can be obtained in strong alkaline solution; this species behaves as tetraprotic base (log K1 = 11.06, log K2 = 9.85, log K3 = 8.46, log K4 = 2.38). L forms mono- and dinuclear complexes in aqueous solution with all the transition metal ions examined; the dinuclear species show a [M2(L-H)2]2+ stoichiometry in which the ligand/metal ratio is 2:2. The studies revealed that two mononuclear [ML-H]+ species self-assemble, giving the dinuclear complexes, which can be easily isolated from the aqueous solution due to their low solubility. This behavior is ascribed to the fact that L does not fulfill the coordination requirement of the ion in the mononuclear species and to the capacity of the phenolic oxygen, as phenolate, to bridge two metal ions. All three dinuclear species were characterized by determining their crystal structures, which showed similar coordination patterns, where all the single metal ions are substantially coordinated by three amine functions and two oxygen atoms of the phenolate moieties. The two metals in the dinuclear complexes are at short distance interacting together as shown by magnetic measurements performed with Ni(II) and Cu(II) complexes, which revealed an antiferromagnetic coupling between the two metal ions. The [Cu2(L-H)2]2+ cation shows a phase transition occurring by the temperature between 100 and 90 K; the characterization of the compounds existing at different temperatures was investigated using X-ray single-crystal diffraction, EPR, and magnetic measurements.     

Pyrazolate-based copper(II) and nickel(II) [2 x 2] grid complexes: protonation-dependent self-assembly, structures and properties

The pyrazole-based diamide ligand N,N'-bis(2-pyridylmethyl)pyrazole-3,5-dicarboxamide (H(3)L) has been structurally characterised and successfully employed in the preparation of [2 x 2] grid-type complexes. Thus, the reaction of H(3)L with Cu(ClO(4))2.6H(2)O or Ni(ClO(4))2.6H(2)O in the presence of added base (NaOH) affords the tetranuclear complexes [M(4)(HL(4))].8H(2)O (1: M = Cu, 2: M = Ni). Employment of a mixture of the two metal salts under otherwise identical reaction conditions leads to the formation of the mixed-metal species [Cu(x)Ni(4-x)(HL)(4)].8H(2)O (x相似文献   

Synthesis and characterization of metal(II) complexes of poly(3-nitrobenzylidene-1-naphthylamine-co-succinic anhydride)

The alternating copolymer poly(3-nitrobenzylidene-1-naphthylamine-co-succinic anhydride) was synthesized from the Schiff base, 3-nitrobenzylidene-1-naphthylamine and succinic anhydride using hydroquinone monomethyl ether under nitrogen atmosphere. The molecular weight of the copolymer was determined by gel permeation chromatography. The metal-polymer complexes were synthesized by the reaction of THF solution of the alternating copolymer with aqueous solution of Cu(II) and Ni(II) acetates. The elemental analysis of the metal-polymer complexes suggests that the metal to ligand ratio is 1:2. The IR spectral data indicate that the metal ions are coordinated through the oxygen of the keto and ester groups. The UV-Visible, magnetic moments and ESR studies indicate square planar geometry for Cu(II) and distorted octahedral geometry for Ni(II) complexes. XRD studies revealed that the copolymer and its Cu(II) complex are crystalline, while the Ni(II) complex is amorphous. The intrinsic viscosity of the copolymer, thermal properties of metal-polymer complexes and their catalytic activity are discussed.     

Physicochemical characterization,thermal, and electrical conductivity studies of some transition metal complexes of bis-chelating Schiff base

Polychelates of Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), and VO(IV) with a new bis-chelating Schiff base derived from 5-acetyl-2,4-dihydroxyacetophenone and isonicotinic acidhydrazide have been synthesized. The resulting polychelates have been characterized by elemental analyses, IR and electronic spectral data, magnetic susceptibility measurements and thermogravimetric analysis. All the polychelates are dark coloured solids and insoluble in water and common organic solvents. Thermogravimetric analyses confirm coordination of water in complexes. Various kinetic and thermodynamic parameters have been evaluated from thermal data. The ligand acts as a bis-tridentate molecule coordinating through deprotonated phenolic/enolic oxygen atoms and azomethine nitrogen atoms. The solid-state conductivity of ligand and its polychelates have been measured in their compressed pellet form and all compounds were found to be semiconducting in nature.     

Transition metal complexes of isonicotinic acid (2-hydroxybenzylidene)hydrazide

A new series of transition metal complexes of Schiff base isonicotinic acid (2-hydroxybenzylidene)hydrazide, HL, have been synthesized. The Schiff base reacted with Cu(II), Ni(II), Co(II), Mn(II), Fe(III) and UO2(II) ions as monobasic tridentate ligand to yield mononuclear complexes of 1:2 (metal:ligand) except that of Cu(II) which form complex of 1:1 (metal:ligand). The ligand and its metal complexes were characterized by elemental analyses, IR, UV-vis, mass and 1H NMR spectra, as well as magnetic moment, conductance measurements, and thermal analyses. All complexes have octahedral configurations except Cu(II) complex which has an extra square planar geometry distorted towards tetrahedral. While, the UO2(II) complex has its favour hepta-coordination. The ligand and its metal complexes were tested against one strain Gram +ve bacteria (Staphylococcus aureus), Gram -ve bacteria (Escherichia coli), and Fungi (Candida albicans). The tested compounds exhibited higher antibacterial activities.     

Polymer-Metal Complexes: Synthesis and Characterization of Poly-(2-Hydroxy-4-acryloxyacetophenone-semicarbazone) Metal Complexes

Abstract

2-Hydroxy-4-acryloxyacetophenone (HAAP) was synthesized and polymerized in 2-butanone using benzoyl peroxide as initiator at 65 °CC. Poly(2-hydroxy-4-acryloxyacetophenone-semicarbazone) (HAAPS) was prepared from poly(HAAP) and semicarbazide hydrochloride and was characterized by IR and NMR spectral studies. The molecular weights of the polymer was determined by gel permeation chromatography. Cu(II) and Ni(II) chelates of poly(HAAPS) were synthesized. Thermogravimetric analysis of the polychelates have been carried out. Elemental analysis of the poly chelates suggest a metal to ligand ratio as 1:2. The polychelates were also characterized by infrared, electronic spectral studies, magnetic, and conductivity measurements.     

Synthesis,Spectroscopic and Electrochemical Studies of Novel Transition Metal Complexes with Quadridentate Schiff Base

A novel quadridentate, N₂O₂ type Schiff base, synthesized from 1,4‐bis‐(o‐aminophenoxy)butane and 2‐hydroxynaphthalin‐1‐carbaldehyde, forms stable complexes with transition metal ions such as Co(II), Cu(II) and Ni(II) in DMF. Microanalytical data, elemental analysis, magnetic measurements, UV‐visible and IR‐spectra as well as conductance measurements were used to confirm the structures. Electrochemical measurements show that metal complexes undergo quasi‐reversible one‐electron redox processes. The voltammetric results also revealed that the CuL complex has the highest electron transfer rate indicating that both the Cu(II) and Cu(I) forms appear in a similar planar configuration, so the electron transfer does not require larger reorganization of the complex.