Fatma Karipcin

Structural, antimicrobial and computational characterization of 1-benzoyl-3-(5-chloro-2-hydroxyphenyl)thiourea.

A new thiourea derivative, 1-benzoyl-3-(5-chloro-2-hydroxyphenyl)thiourea (bcht) has been synthesized from the reaction of 2-amino-4-chlorophenol with benzoyl isothiocyanate. The title compound has been characterized by elemental analyses, FT-IR, (13)C, (1)H NMR spectroscopy and the single crystal X-ray diffraction analysis. The structure of bcht derived from X-ray diffraction of a single crystal has been presented. The structural and spectroscopic data of the molecule in the ground state were calculated by using density functional method using 6-311++G(d,p) basis set. The complete assignments of all vibrational modes were performed on the basis of the total energy distributions (TED). Isotropic chemical shifts ((13)C NMR and (1)H NMR) were calculated using the gauge-invariant atomic orbital (GIAO) method. Theoretical calculations of bond parameters, harmonic vibration frequencies and nuclear magnetic resonance are in good agreement with experimental results. The UV absorption spectra of the compound that dissolved in ACN and MeOH were recorded. Bcht was also screened for antimicrobial activity against pathogenic bacteria and fungi.

Synthesis, Characterization, Thermal Behavior, and DNA-Cleaving Studies of Cyano-Bridged Nickel(II)Copper(II) Complexes of 4-(Pyridin-2-ylazenyl)resorcinol

We present here the syntheses of a mononuclear CuII complex and two polynuclear CuIINiII complexes of the azenyl ligand, 4‐(pyridin‐2‐ylazenyl)resorcinol (HL; 1). The reaction of HL (1) and copper(II) perchlorate with KCN gave a mononuclear complex [CuL(CN)] (4). Using 4, one pentanuclear complex, [{CuL(NC)}4Ni](ClO4)2 (5) and one trinuclear complex, [{CuL(CN)}2NiL]ClO4 (6), were prepared and characterized by elemental analyses, magnetic susceptibility, molar conductance, IR, and thermal analysis. Stoichiometric and spectral results of the mononuclear CuII complex indicated that the metal/ligand/CN ratio was 1 : 1 : 1, and the ligand behaved as a tridentate ligand forming neutral metal chelates through the pyridinyl and azenyl N‐, and resorcinol O‐atom. The interaction between the compounds (the ligand 1, its NiII and CuII complexes without CN, i.e., 2 and 3, and its complexes with CN, 4–6) and DNA has also been investigated by agarose gel electrophoresis. The pentanuclear Cu4Ni complex (5) with H2O2 as a co‐oxidant exhibited the strongest DNA‐cleaving activity.

MONO-, TRINUCLEAR NICKEL(II) AND COPPER(II) DIOXIME COMPLEXES: SYNTHESIS, CHARACTERIZATION, CATECHOLASE AND CATALASE-LIKE ACTIVITIES, DNA CLEAVAGE STUDIES

The synthesis and molecular structures of six new mono- and trinuclear complexes [M1L 2 {M2(phen)} 2 ](ClO 4 ) 2 [phen = 1,10-phenanthroline, H 2 L = dioxime ligand, M1, M2 =Ni(II) and Cu(II)] of the ligand, 4-(4-methylphenylamino)biphenylglyoxime are reported. Structural assignments are supported by a combination of FT-IR, elemental analyses, ICP-OES, magnetic susceptibility and molar conductivity studies. Furthermore these complexes were each tested for their ability to catalyze the oxidation of catechol substrates to quinone with dioxygen at 25oC and disproportionation of hydrogen peroxide in the presence of the added base imidazole. The catalytic results indicated that the heterotrinuclear Cu(II)Ni(II)Cu(II) complex (5) shows greater catecholase activity. On the other hand the trinuclear complexes display efficiency in disproportion reactions of hydrogen peroxide producing water and dioxygen in catalase-like activity and homotrinuclear Cu(II) (6) complex is more active towards catalytic decomposition of hydrogen peroxide. The interaction between these compounds with DNA has also been investigated by agarose gel electrophoresis, the trinuclear copper(II) complexes (5, 6) with H 2 O 2 as a cooxidant exhibited the strongest cleaving activity.

Oxime-functionalized cryogel disks for catalase immobilization

Catalase is a protective enzyme against oxidative stress and converts hydrogen peroxide into water and molecular oxygen. In the current study, catalase immobilization was applied onto the oxime-functionalized cryogel disks. Cryogel disks were produced by free radical polymerization. After cutting as circular disks, oxime ligand (4-biphenylchloroglyoxime, BPCGO) was attached and oxime-functionalized cryogel disks were obtained. After optimization of several immobilization parameters such as pH, initial catalase concentration, temperature and ionic strength, maximum catalase load was detected as 261.7 ± 11.2mg/g for cryogel disk at pH5.0. Activity studies indicated that immobilization enhanced the enzyme activity in basic pH region, the temperature range of 15-35°C and at ionic strengths between 0.2 and 1.0M NaCl. Km was detected as 9.9 and 11.0mM and Vmax was 357.1 and 769.2μmol min-1 for free and immobilized catalase, respectively. kcat and Km/kcat values showed that immobilization enhanced the catalytic efficiency. Storage stability experiments demonstrated that immobilization increased the usability period. Furthermore, catalase desorption was achieved by 1.0M NaSCN at pH8.0 successfully and catalase adsorption capacity of oxime-functionalized cryogel disk was decreased by 9.9% at the end of 5 adsorption-desorption cycle.

Preparation and characterization of magnetic polysulfone/thiourea microcapsules and their application for Cr(III) removal

In this study, novel magnetic polysulfone microcapsules based on N-Benzoyl-N’-(4-methylphenyl) thiourea (TTU) were prepared with the phase inversion method. Characterization of the microcapsules was performed by using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and thermogravimetric analysis (TGA) techniques. The investigation of the adsorption properties of prepared microcapsules for the Cr(III) ion in the aqueous solution were evaluated. The parameters affecting the adsorption such as pH, contact time, amount of adsorbents (microcapsules), temperature and concentration were examined. Langmuir and Freundlich adsorption isotherms were studied to investigate the suitability of adsorption mechanism. The adsorption behavior of Cr(III) ions was found to be appropriate for the Langmuir isotherm. Cr(III) ion adsorption is spontaneous and exothermic and the adsorption process is more suitable to pseudo second order kinetic model according to the thermodynamic and kinetic analysis of the experimental data. Besides, real wastewater sample was used in order to highlight the effects of background water chemistry. Tannery wastewater was used for the removal of Cr(III) ions. Cr(III) ions were effectively removed by 87.54%.

Synthesis, characterization and electrochemical behavior of a new diimine-dioxime compound and its application in developing Hg(II)-selective membrane electrode

In this work, a new diimine-dioxime compound (N,N′-bis[1-biphenyl-2-hydroxyimino-2-(4-chloroanilino)-1-ethylidene]-1,4-phenylenediamine) was synthesized and characterized by a combination of elemental analyses, FT-IR, 1H- and 13C-NMR spectra. The extraction ability of the new compound has been examined in chloroform by using several transition metal picrates such as Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Pb(II), Cd(II) and Hg(II). It has been observed that diimine-dioxime compound shows a high affinity to Hg(II) ion. The electrochemical measurements of the compound were performed by cyclic voltammetry in acetonitrile solution at room temperature, and two irreversible oxidation waves were observed. A Hg(II)-selective electrode based on the diimine-dioxime compound has been developed. The electrode showed linear responses with Nernstian slopes of 33 ± 1 mV per decade over a wide concentration range (1.0 × 10−2–8.0 × 10−6 M). The limit of detection was 2.4 × 10−6 M. The electrode has a response time about 10–15 s and it did not show a considerable divergence in its potential response over a period of 1 month. The proposed electrode revealed selectivity towards Hg(II) ion in the presence of various cations. The electrode could be used over a wide pH range of 4.0–9.0. The electrode can be successfully used as an indicator electrode for potentiometric titration of Hg(II) with EDTA.

Synthesis, characterization, and sorption properties of silica gel-immobilized Schiff base derivatives

AbstractIn this study, two Schiff base ligands were synthesized and characterized by Elemental analysis, infrared spectroscopy and nuclear magnetic resonance, respectively. The silica gel surface was, respectively immobilized with Schiff base derivatives, 4-(4-(4-[1-methyl-3-oxobutidenamino]fenil] fenilimino)-2-pentanon (BAA) and 4-{5-[1-methyl-3-oxobutylideneamino]-1-naphthylimino}-2-pentanone (NAA), after surface modification by 3-aminopropyltrimethoxysilane (APTS) to prepare new adsorbents. Characterization of the surface modification was confirmed through elemental analysis, thermogravimetry and scanning electron microscopy. The immobilized silica gels (Si–APTS–BAA and Si–APTS–NAA) were used for sorption of Cu(II) ion in aqueous solution. The influence of the pH, amount of adsorbent, ion concentration, time, and temperature was investigated. The characteristics of the sorption process were evaluated by using the Langmuir and Freundlich sorption isotherms. The sorption of Cu(II) metal ion onto modified...

Synthesis and Characterization of Novel Organocobaloximes as Potential Catecholase and Antimicrobial Activity Agents

An asymmetric, potentially bidentate dioxime ligand (H2L) was formed by condensation of 4‐biphenylchloroglyoxime and napthyl‐1‐amine. Two equivalents of H2L were reacted with CoCl2 · 6H2O under appropriate conditions with deprotonation of the dioxime ligand. A series of new organocobaloxime derivatives of the type [CoR(HL)2Py], [CoRL2PyB2F4], and [CoRL2Py(Cu(phen))2] (H2L = 4‐(napthyl‐1‐amino)biphenylglyoxime; phen = 1,10‐phenathroline; R = izopropyl and benzyl; Py = pyridine) were synthesized. The products were characterized by elemental analysis, molar conductance, FT‐IR, 1H NMR, and magnetic susceptibility measurements. Catecholase‐like activity properties of all complexes were also studied. All complexes are catalysts for the oxidation of 3,5‐di‐tert‐butylcatechol to 3,5‐di‐tert‐butyl‐1,2‐benzoquinone in methanol. Antimicrobial activity studies of H2L and the six complexes were carried out on standard strains (human pathogenic) of bacteria (Staphylococcus aureus, methicillin‐resistant S. aureus (MRSA), Bacillus cereus, Enterococcus faecalis, Streptococcus pneumoniae, Listeria monocytogenes, Bacillus subtilis, Escherichia coli, Pseudominas aeruginosa, Salmonella typhi) and the yeast Candida albicans. The compounds showed a significant inhibition of the growth of the Gram‐positive bacteria tested. Among the tested microorganisms, S. aureus was the most sensitive strain, especially to H2L and its complexes.

Synthesis, Characterization, Electrochemical Behavior, and Biological Studies of 1-p-Diphenylmethane-2-hydroxyimino-2-(arylamino)-1-ethanone Copper(II) and Ruthenium(III) Complexes

New copper and ruthenium mononuclear complexes of the type [ML2(H2O)X] [X = H2O for M = Cu(II) and X = Cl for M = Ru(III)] have been prepared from 1-p-diphenyl- methane-2-hydroxyimino-2-(4-chloroanilino)-1-ethanone (HL1) and 1-p-diphenylmethane-2-hydroxyimino-2-(4-toluidino)-1-etha- none (HL2). The complexes were characterized by elemental analyses, magnetic susceptibility, molar conductance, IR, thermal analysis, and cyclic voltammetry. Stoichiometric and spectral results of the metal complexes indicated that the metal:ligand ratios in the complexes were found to be 1:2 and the ligands behave as a bidentate ligand forming neutral metal chelates through the carbonyl and oxime oxygen. The electrochemical behavior of the ligands and their complexes were obtained by cyclic voltammetry. The interaction between these complexes with DNA has also been investigated by agarose gel electrophoresis. The copper(II) complexes (3 and 4) with H2O2 as a co-oxidant exhibited strongest cleaving activity. Moreover, catalytic activities of the complexes for the disproportionation of hydrogen peroxide were also investigated in the presence of imidazole.

4,4'-(DIPHENYLMETHANE-4,4'-DIYLDINITRILO)DIPENTAN-2-ONE AND 4,4'-(DIPHENYLETHER-4,4'-DIYLDINITRILO)DIPENTAN-2-ONE LIGANDS AND THEIR Ni(II), Cu(II) COMPLEXES: SYNTHESIS, CHARACTERIZATION, DNA CLEAVAGE STUDIES

The synthesis of two new ligands 4,4’-(diphenylmethane-4,4’-diyldinitrilo)dipentan-2-one (H 2 L1) and 4,4’-(diphenylether-4,4’-diyldinitrilo)dipentan-2one (H 2 L2) is reported. The ligands have two acetylacetone subunits separated by diphenylmethane or diphenylether group. The ligands form stable dinuclear complexes with Ni(II) and Cu(II) ions. Ligands and their complexes were characterized by elemental analysis, m.p., IR, molar conductivity and magnetic moment measurements. The interaction between these compounds with DNA has also been investigated by agarose gel electrophoresis, we found that the nickel(II) and copper(II) complexes can cleave supercoiled pBR322 DNA to nicked and linear forms. The copper(II) complexes with H 2 O 2 as a cooxidant exhibited the strongest cleaving activity. The free ligands were also characterized by 1H NMR spectra. The IR of the free ligands and their complexes are compared and discussed. The extraction ability of the ligands have been examined by the liquid–liquid extraction of selected transition metal [Mn2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Hg2+ and Pb2+] cations. The ligands show strong binding ability toward mercury(II) ion.