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.     

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.     

Transition metal polymeric chelates: Spectral, magnetic, thermal behaviour of polymeric chelates of poly(resacetophenone diyl ethylene)s with Ni(II), Cu(II), Mn(II), Zn(II) and Co(II)

Polymeric chelates of the type [ML₂]_n where M = Ni(II), Cu(II), Zn(II) or Co(II), L = poly(resacetophenone diyl ethylene)s, andn= degree of polymerization, have been synthesized. Their structures have been elucidated on the basis of analytical, magnetic, electronic and IR spectral studies. Electronic spectra in conjunction with magnetic moments are in accord with an octahedral environment around the central metal ion in all polymeric chelates except Cu(II) and Zn(II) polymeric chelates which have been shown to possess square planar and tetrahedral geometries, respectively. IR spectral studies further suggest that the metal ions are coordinated through the oxygens of the carbonyl and the phenolic hydroxyl groups. All the chelates are paramagnetic except Zn(II), which is found to be diamagnetic.     

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,Characterization, Thermal and Antimicrobial Activity of Poly[(2‐Hydroxy‐4‐methoxy benzophenone)propylene] and its Polychelates with Lanthanides(III)

The polymeric ligand (resin) was prepared from 2‐hydroxy‐4‐methoxy‐benzophenone with propylene glycol in the presence of polyphosphoric acid as a catalyst at 160°C for 13 h. The poly[(2‐hydroxy‐4‐methoxybenzophe‐none) propylene] H(HMBP‐PG) form 1:2 metal:ligand chelates with La(III), Pr(III), Nd(III), Sm(III), Gd(III), Tb(III) and Dy(III). The polymeric ligand and its polychelates were characterized on the basis of elemental analyses, electronic spectra, magnetic susceptibilities, IR‐spectroscopy, NMR, and thermogravimetric analyses. The molecular weight was determined using Number Average Molecular Weight (Mn) by a Vapor Pressure Osmometry (VPO) method. All the polychelates are paramagnetic in nature. The resin and their polychelates were tested for antimicrobial activity against E. coli, B. substilis, S. aureus (bacteria) and S. cerevisiae (yeast). It is found that the synthesized polychelates can be used as antibacterial agents.     

Metal chelates of ampicillin versus amoxicillin: synthesis,structural investigation,and biological studies

Solid chelates derived from some alkaline earth and transition metal complexes with ampicillin (Hamp, a) and amoxicillin (Hamox, b) were synthesized and characterized using elemental analysis, molar conductivity, IR, magnetic susceptibility, and thermogravimetric studies. Both drugs behave as tetradentate ligands coordinating to metal through amino, imino, and carboxylate as well as through β-lactamic carbonyl. All chelates have octahedral geometry except Cu(II) complexes which have square planar structure and uranium has pentagonal bipyramidal coordination. ¹H- and ¹³C-NMR of the Zn(II) and UO₂(VI) chelates are compared with the free ligands. The antimicrobial activity of the prepared chelates was determined.     

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.     

Nitroxoline Azo Dye Complexes as Effective Heterogeneous Catalysts for Color Removal and Degradation of Some Organic Textile Dyes

A new azo dye ligand of sulfadiazine with 5‐nitro‐8‐hydroxyquinoline (H₂L) and its Cu(II), Mn(II), Co(II), and Ni(II) complexes have been synthesized and characterized using CHN, ¹H NMR, EI‐mass, inductive coupled plasma, molar conductance, IR, thermogravimetric analysis, magnetic moment measurements, and UV–vis spectra. On the basis of spectral studies and analytical data, the azo dye acts as a monobasic bidentate ligand coordinating to the metal ions via deprotonated OH and azo nitrogen atom. The spectral data showed that the synthesized complexes have octahedral geometry. The application of the obtained chelates in the oxidative decomposition of three different textile dyes (i.e., AB92, AB40, and AB129) in the presence of H₂O₂ as an oxidant has been studied. The obtained results indicated that the reactivity of catalysts toward the decolorization of AB40 showed the following order: Cu complex > Ni complex > Co complex > Mn complex; the reactions obey the first‐order reaction mechanism, and the rate constants were determined.     

Polymer complexes. LV. Spectroscopic,thermal studies,and coordination of metal ions N-[3-(5-amino-1,2,4-triazolo)] acrylamide polymer complexes

Novel polymeric complexes with a potentially bidentate ligand formed by amidation of 3,5-diamino-1,2,4-triazole with acryloyl chloride were synthesized and characterized on the basis of elemental analyses, IR, ¹H-NMR, UV-Vis, magnetic susceptibility measurements, molar conductance, and thermal analyses. The molar conductance data reveal that all the polymer complexes are non-electrolytes. Spectral studies reveal that the free ligand coordinates bidentate to the metal ion through the oxygen of the carbonyl and azomethine of the heterocyclic ring. Elemental analyses of the polychelates indicate the metal to ligand ratio of 1?:?1/1?:?2. On the basis of electronic spectral data and magnetic susceptibility measurements, suitable geometry has been proposed for each polymeric complex. The electron spin resonance spectral data of the Cu(II) complex showed that the metal–ligand bonds have considerable covalent character. The thermal behavior of these chelates shows that the polymer complexes lose coordinated water in the first step immediately followed by decomposition of the anions and ligand molecules in a subsequent step.     

Metal chelates of 1-acetylpyridinium chloride-4-phenyl-3-thiosemicarbazide

The metal chelates of 1-acetylpyridinium chloride-4-phenyl-3-thiosemicarbazide [(APTS)]⁺Cl^? of the type [M(APTS)X₂]⁺ Cl^? (M = Co(II), Ni(II), Cu(II), Zn(II) or Cd(II); X = Cl, Br or $\text{1}\text{2}$SO₄) have been prepared and characterized on the basis of elemental analysis, molar conductance, IR, electronic spectra and magnetic studies. IR spectral studies showed that the ligand coordinates via thioketo and NLH groups. Magnetic and spectral studies suggest a tetrahedral structure for Ni(II), pseudo-tetrahedral for Co(II) and square planar and/or distorted tetrahedral for Cu(II) chelates.     

Comparative Sites for Coordination of Naphthoquinones and its Derivatives: Studies on the Synthesis of a Series of 1,4-Naphthoquinone Derivatives and Their Ni(II) Complexes

Abstract

New derivatives (5–8) of 5-amino-8-hydroxy-1,4-naphthoquinone (1) have been synthesized and characterized by IR, UV-Vis, ¹H NMR, mass spectra and CNH. These new ligands and the 5-amino-8-hydroxy-l,4-naphthoquinone (1), the 5-amino-6-bromo-8-hydroxy-1,4-naphtho-quinone (2), the 5-acetylamino-8-hydroxy-1,4-naphthoquinone (3) and the 5-dodecanoylamino-8-hydroxy-1,4-naphthoquinone (4), were complexed with Ni(II) giving the chelates (1a–8a). The structure and site of coordination of these complexes are discussed in relation to their spectroscopic data and thermal analysis.     

Spectral,Antimicrobial, and Thermal Studies of Some Transition Metal Complexes Derived from Bidentate Ligands Containing N and S Donor Atoms

Abstract

Bidentate ligands have been synthesized by the reaction of 2,4-dichlorobenzaldehyde with 4-amino-5-mercapto-1,2,4-triazole and 4-amino-5-mercapto-3-propyl-1,2,4-triazole. The ligands react with acetates of Co(II), Ni(II), Cu(II), and Zn(II) to yield 1:2 [metal:ligand] complexes. The newly synthesized compounds were characterized by elemental analyses, spectral (UV-Vis, IR, ¹H NMR, fluorescence, ESR) studies, thermal techniques, and magnetic measurements. Thermal studies of the complexes showed a multistep decomposition pattern. A square planar geometry for Cu(II) and octahedral geometry for Co(II), Ni(II), and Zn(II) complexes have been proposed. The synthesized complexes exhibit enhanced antimicrobial activity against Staphylococcus aureus, Bacillus subtilis, Aspergillus niger, and A. flavus compared to parent ligands. However, tested compounds did not exhibit any activity against Escherichia coli and Pseudomonas aeruginosa.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

Thermal and electrical studies of some polychelates

Polychelates of Mn(II), Fe(II), Co(II), Ni(II), and Cu(II) with 4,4′-dihydroxy-3,3′-diacetylbiphenyl-dithioxamide (DDBDO) have been prepared. Their structures were determined by visible reflectance spectroscopy and magnetic measurements in conjunction with thermogravimetric and IR measurements. Elemental analysis indicates a 1∶1 metal-ligand stoichiometry and the association of water molecules with the central metal. The decomposition temperature of the chelates is in the order Ni(II)>Fe(II)>Co(II)>Mn(II)>Cu(II). Thermal activation energies (E _a ), calculated with the help of Freeman-Carroll and Sharp-Wentworth methods, are in agreement with each other. The polychelates were found to be semiconductive, and the activation energy obtained from semiconducting behavior follows the order Co(II)>Ni(II)>Fe(II)>Cu(II)>Mn(II). The probable structure, such as six coordinated octahedral for Mn(II) and Fe(II) polychelates and four coordinated square planar for Co(II), Ni(II), and Cu(II) polychelates, have been suggested.     

Synthesis and In Vitro Anti-HIV Activity of Some New Schiff Base Ligands Derived from 5-Amino-4-phenyl-4H-1,2,4-triazole-3-thiol and Their Metal Complexes

New Schiff base ligands (6–9) derived from 5-amino-4-phenyl-4H-1,2,4-triazole-3-thiol 1 and substituted benzaldehydes (2–5) as well as their metal complexes with Cu(II), Fe(II), Au(III), and Mn(II) (12–17) have been synthesized. A new benzothiazole derivative (11) was prepared from coupling of 7 with N-(benzothiazol-2-yl)-2-chloroacetamide 10. Their spectral properties were investigated. The newly designed and synthesized Schiff base ligands and the metal complexes were assayed for anti-HIV-1 and HIV-2 activity by examination of their inhibition of HIV-induced cytopathogenicity in MT-4 cells. Compounds 11 and 16 were found to be the most active inhibitors in cell culture (EC₅₀ = 12.2 μg/mL (SI = 4) and > 2.11 μg/mL (SI = > 1), respectively) against HIV-1, whereas 11 showed inhibition against HIV-2 of EC₅₀ > 10.2 μg/mL with SI = 9, which provided a good lead for further optimization.     

钴(Ⅱ)、镍(Ⅱ)、铜(Ⅱ)、锌(Ⅱ)的双-N(2-羟基乙基)水杨醛亚胺螯合物的合成及其抗癌活性的初步试验

合成了-N(2-羟基乙基)水杨醛亚胺合钴(Ⅱ)、镍(Ⅱ)、铜(Ⅱ)和锌(Ⅱ)并为元素分析和红外光谱数据所表征。其中三种螯合物为新的席地夫碱金属配合物。用体外美兰法对Co(Ⅱ)、Ni(Ⅱ)和Cu(Ⅱ)配合物进行了抗癌活性试验。结果表明,这些螯合物对六种人体肿瘤具有抑瘤活性。     

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,characterization and applications of coordination polymers of Ln(III)

The resin was synthesized by condensation of 2‐hydroxy‐4‐ethoxybenzophenone with 1,4‐butane diol in presence of polyphosphoric acid as a catalyst at 155 °C for 10 h. The synthesized resin was used to get polychelates of 4f‐block elements. The resin and its polychelates were characterized on the basis of elemental analyses, electronic spectra, magnetic susceptibilities, FTIR, NMR and thermogravimetric analyses. Morphological study of resin and polychelates were carried out by scanning electron microscope. The number average molecular weight (M?_n) was determined using a vapor pressure osmometry method. The catalytic activity of selected polychelates was examined for organic synthesis. It is observed from the study that polychelates give excellent results. They were found to be efficient and effective catalysts and antimicrobial agents. Copyright © 2008 John Wiley & Sons, Ltd.     

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.     

Untersuchungen über Bildung von Komplexen von Arylaminoanthrachinonen mit zweiwertigen Ionen von Übergangsmetallen, 1. Mitt.: Komplexe von Alizarin-cyaningrün und Alizarin-reinblau B mit Fe(II), Mn(II), Co(II), Ni(II) und Cu(II)

The complexes of 1,4-di(4-methylanilino)-anthraquinone (alizarin cyanin green) and 1-amino-2-bromo-4(2-sulpho-4-methylanilino)anthraquinone (alizarin pure blue B) with Fe(II), Mn(II), Co(II), Ni(II) and Cu(II) have been investigated and characterized on the basis of elemental analysis, conductometric, electronic and infrared spectral studies. The values of logB ^* for the different complexes are determined. I. R. spectra of the ligands in the solid chelates indicate that the bonding sites in the chelates are the -imino-nitrogen and the oxygen of its neighbouring C=O group. The chelate formation leads to proton displacement.     

The Synthesis and Characterization of a Novel ( E,E )-Dioxime and its Mono- and Heterotrinuclear Complexes Containing an 18-Membered Dioxadithiadiazamacrocycle

The novel ( E , E )-dioxime, 5,6:17,18-dibenzo-11,12-(4'-nitrobenzo)-2,3-bis(hydroxyimino)-7,16-dithia-10,13-dioxa-1,4-diazacyclooctadecane) ( H 2 L ), has been synthesized from reaction of ( E , E )-dichloroglyoxime ( 1 ) with 2,3:14,15-dibenzo 8,9-(4'-nitrobenzo)-4,13-dithia-7,10-dioxa-1,16-diazahegzadecane ( 2 ). The mononuclear Co(III) complex ( 4 ) of this dioxime was prepared by oxidation of the cobalt (II) complex. The -capped Co(III) complex ( 5 ) was synthesized by using a precursor Co(III) complex and boron trifluoride dietherate. The heterotrinuclear complexes ( 6 ) and ( 7 ) were prepared by reaction of ( 5 ) with NiCl 2 ·6H 2 O and CdCl 2 ·H 2 O, respectively. In addition, the homotrinuclear Cu(II) complex ( 8 ), has also been prepared by the reaction of this dioxime with CuCl 2 ·H 2 O. The structures of the dioxime and its complexes were identified by using elemental analysis, 1 H- and 13 C-NMR, IR, and mass spectral data.