Composition ML2 Research Articles

Synthesis, structure, and photoluminescence of Zn(II) and Cd(II) complexes with N-[2-(diethylaminoalkyliminomethyl)-phenyl]-4-methylbenzenesulfonamides

Zn(II) and Cd(II) complexes based on N-[2-(diethylaminoalkyliminomethyl)-phenyl]-4-methylbenzenesulfonamide (HL) of composition ML2 and MHLCl2 were synthesized. The structures of the complexes were established by elemental analysis, IR, 1H NMR, UV spectroscopy, X-ray absorption spectroscopy (EXAFS), and X-ray crystallography. The complexes demonstrate photoluminescent properties in the blue-violet region of the spectrum with the maxima of the PL bands at 426–448 nm and quantum yields of 0.2–0.34.

СИНТЕЗ, СТРОЕНИЕ И СВОЙСТВА КОМПЛЕКСНЫХ СОЕДИНЕНИЙ КОБАЛЬТА(II) C ПРОИЗВОДНЫМИ БЕНЗОКСАЗИНОВ

In this work, coordination compounds of Co (II) with derivatives of dihydro-4H-3,1-benzoxazines were synthesized by a chemical method and their composition, structure, and physicochemical properties were studied. ... According to the data of elemental analysis and analysis for metal, the obtained complex compounds have the composition ML2, where M is metal, L are ligands: 2- [2-hydroxyphenyl] -4,4-diphenyl-1,2-dihydro-4H-3,1benzoxazine (L1), 2- [2-hydroxy-5-nitrophenyl] -4,4-diphenyl-1 , 2-dihydro-4H-3,1-benzoxazine (L2), 2- [2hydroxynaphthyl] -4,4-diphenyl-1,2-dihydro-4H-3,1-benzoxazine (L3), 2- [ 2-hydroxynaphthyl] -4,4-diethyl-1,2dihydro-4H-3,1-benzoxazine (L4). The structure and properties of the obtained complex compounds were studied by IR spectroscopy. According to IR spectroscopy data, it was found that in all complex compounds, the ligand participates in the open azomethine form; coordination with the metal atom involves two oxygen atoms and a nitrogen atom of the azomethine fragment of the ligand. It was found that the ligand in the complex performs a tridentate chelate-bridging function. The structure of complex compounds of cobalt with derivatives of benzoxazines is proposed.

Metal Chelates of Tridentate (NNO) 1,2,4-Triazine Schiff Base: Synthesis, Physico-chemical Investigation and Pharmacological Screening

Present work portray the synthesis of four new tridentate Schiff base ligand transition metal chelates having 1,2,4-triazine and 1,4-Naphthoquinone as a potential drug candidate, with composition ML2, where M=Co(II), Ni(II), Cu(II) and Zn(II); L = 4-(2-(5,6-diphenyl-1,2,4-triazin-3-yl)hydrazono)-3-hydroxynaphthalene-1(4H)-one (DTN). Credible structure of the synthesized compounds was investigated using different techniques like elemental analysis, molar conductance, mass spectra, magnetic susceptibility, UV–Visible, IR, NMR and TGA. The results were unfailing with tridentate nature of the ligand and octahedral geometry of metal chelates. Thermal scrutiny of the synthesized complexes exemplified absence of coordinated water molecules, decomposition patterns of the complexes and their stabilities. Furthermore, redox behaviour of the synthesized compounds was examined by cyclic voltammetry in DMSO solution. Antimicrobial screening tests played a pivotal role in displaying the presence of metal ion in the ligand system. Chemical nuclease activity was investigated to study the DNA cleavage activities of the synthesized compounds and effectual cleavage was revealed by Co(II) and Cu(II) metal chelates of DTN.

Studies on Inclusion Complexes of β-Cyclodextrin with Some Metal Complexes of Isatinylsemicarbazone and Isatinylthiosemicarbazone

The complexes of Co(II), Ni(II), Zn(II) and Cd(II) with isatinylsemicarbazone (IstscabH) and isatinylthiosemicarbazone (IsttscabH) of composition ML2·2H2O [M = Co(II) or Ni(II) and LH = IstscabH or IsttscabH] and ML2 [M = Zn(II) or Cd(II) and LH = IstscabH or IsttscabH] have been synthesized and their antibacterial activity has been investigated. Their inclusion complexes with β-cyclodextrin (β-CD) having composition [ML2(β-CD)·2H2O] or M(C60H88N8O39S2)], [M = Co(II) or Ni(II) and LH = IstscabH or IsttscabH] and [ML2(β-CD) or M(C60H84N6O-37S2)], [M = Zn(II) or Cd(II) and LH = IstscabH or IsttscabH] have also been isolated in solid states. All the synthesized metal complexes have been characterized by analytical data, molar conductance, magnetic susceptibility, electronic and infrared spectral studies. The tetrahedral geometry for Zn(II) and Cd(II) and octahederal geometry for Co(II) and Ni(II) have been assigned on the basis of magnetic susceptibility, UV electronic transitions and IR spectral bands assignments. The structures are retained in inclusion products. A biological activity of Schiff bases, their metal complexes and inclusion products for bacteria Escherichia. coli, Bacillus subtilis and Staphylococcus aureus have been screened and activity explained.

3-(2-ПІРИДИЛ)-5-(2-ГІДРОКСІФЕНІЛ)-1,2,4-ТРІАЗОЛ ЯК РЕАГЕНТ ДЛЯ ФЛУОРИМЕТРИЧНОГО ВИЗНАЧЕННЯ МІКРОКІЛЬКОСТЕЙ ЦИНКУ

The development of new fluorescent reagents for determination of trace amounts of zinc in biological samples is an actual issue. Efficient reagents should characterized by high hydrophobicity, low sensitivity to media acidity and intense fluorescence in the long-wavelength region of the spectrum. Therefore, the using of a rigid π-conjugated molecule of 3-(2-pyridyl)-5-(2-hydroxyphenyl)-1,2,4-triazole as a fluorescent probe for the determination of zinc micro-quantities in biological samples is considered as a rational choice. 3-(2-pyridyl)-5-(2-hydroxyphenyl)-1,2,4-triazole is a highly hydrophobic ligand (logP=3.0±0.1). Dissociation of the protonated nitrogen atom in the pyridine cycle of the ligand occurs at pH = 4, рКа1= 3.98±0.05. The pKa2 value is equal to 8.74 ± 0.03 and corresponds to the dissociation of the N-H group of the triazole fragment. The absorption spectrum of the ligand solution in DMSO is characterized by two bands with maximum at 272 nm and 320 nm due to intraligand π-π * transitions. The values of the molar absorption coefficient for these bands are 1.18·104 l·mol-1·cm-1 and 1.36·104 l·mol-1·cm-1, respectively. Two bands at 402 nm and 535 nm are also observed on the fluorescence spectra of the ligand. The high fluorescence intensity in the long-wavelength region of the spectrum indicates the promising use of this ligand as an analytical reagent at a creation of new fluoresce techniques. 3-(2-pyridyl)-5-(2-hydroxyphenyl)-1,2,4-triazole as chelating ligand can form two complex compounds in DMSO solution with composition ML and ML2. Complex formation is accompanied by the appearance of a third absorption band in the visible regions of the spectrum at 440 nm (ε440≈ 6,5·103 l·mol-1·cm-1) due to LMCT transitions. In addition, the complex formation leads to fluorescence quenching. Developed fluorescent techniques for determination of zinc quantities in a sample of hair and in a tablet of vitamins "Duovit" are characterized by satisfactory precision and accuracy. The range of zinc concentrations determining in the hair sample is 71–286 μg/g, Sr=0.033 (n=3, P=0.95). The zinc content that was found in the "Duovit" tablet is well correlated with the declared content. This indicates the good selectivity of ligand in relation to the accompanying microelements.

New Tridentate Schiff Base, Product of Condensation of 4-Methyl-7-hydroxy-8-formylcoumarin and N-Aminomercaptotriazole: Synthesis, Structure, and Complex Formation

A new Schiff base was prepared by the reaction of 4-methyl-7-hydroxy-8-formylcoumarin with N-aminomercaptotriazole. In solution and in solid phase the compound was shown to exist in the thione form. The compound reacts with Cu(II), Ni(II), Zn(II) and Cd(II) ions depending on the metal salt to give complexes of composition ML2 or MHLX, where HL is monodeprotonated form of the ligand. Cu(II) and Ni(II) complexes were studied by spectral and magnetochemical methods. The Zn(II) and Cd(II) complexes exhibit fluorescence.

Synthesis and structure of enaminoketones of pyrazole containing 2-thione(selenone)benzimidazolyl fragments and their zinc and cadmium complexes

New ligand systems based on 4-formyl-5-hydroxypyrazole and 1-aminobenzimidazole derivatives are synthesized. The obtained enamines and their Zn2+ and Cd2+ metal complexes of composition ML2 were investigated using the IR, heteronuclear (1H, 13C, 15N, 77Se, 113Cd) and two-dimensional NMR spectroscopy (COSY, HSQC, HMBC). The data of physicochemical investigations and quantum-chemical calculations showed that the ligands exist in the ketoamine tautomeric form. Quantum-chemical simulation of Zn(II) and Cd(II) complexes showed that the zinc complexes adopt the pseudo-tetrahedral and the cadmium complexes pseudo-octahedral configuration.

Chemical and electrochemical synthesis, molecular structures, DFT calculations and optical properties of metal-chelates of 8-(2-tosylaminobenzilideneimino)quinoline

Bis-chelate complexes with composition ML2 (M2+=Co, Ni, Cd and Zn) were synthesized on the basis of potential tridentate N, N, O donor Schiff base ligand – 8-(2-tosylaminobenzilideneimino)quinoline (HL) by both chemical (CS) and electrochemical synthesis (ES). CS of zinc complexes leads to obtaining the compounds with composition ZnLCOOCH3. Structure and properties of the prepared compounds have been studied by means of elemental analysis, IR, 1H NMR spectroscopy as well as quantum-chemical computations. Electronic spectra of UV–Vis absorption and photoluminescence for cadmium and zinc complexes were studied in acetonitrile solution. Crystal structure of zinc and cadmium complexes was determined by X-ray analysis. In the zinc complex ZnN6 coordination site was realized due to involving the nitrogen atom of quinoline fragment in coordination to the metal ion. Meanwhile due to X-ray analysis data cadmium complex possesses CdN6O surroundings with additional coordination of oxygen atom of tosylamino group from one of the ligand. Cobalt and zinc complexes were assigned to have the octahedral structures on the basis of the physical chemical measurements.

Synthesis and Characterization of Co (II), Ni (II) and Cu (II) Complexes With Ethyl -α- Isonitrosoacetoacetate(HEINA)

Ethyl-α-Isonitrosoacetoacetate has been prepared by reacting Ethyl acetoacetate and sodium nitrite. Co (II), Ni (II) and Cu (II) Complexes have been prepared by reacting metal acetate with this ligand Ethyl-αIsonitrosoacetoacetate. All these complexes are dark in colour. They have been characterized by elemental analysis, magnetic measurements and spectral studies. The complexes were found to have composition ML2, where L = Ethyl-α-Isonitrosoacetoacetate and M = Cu (II), Ni (II) and Co (II). On the basis of elemental and spectral studies six coordinated octahedral geometry assign for Co (II), Ni (II) and square plane for Cu (II) complexes. Key-words: Magnetic susceptibility, cobalt, nickel, copper, ethyl-α-isonitrosoacetoacetate

Nickel(II) and copper(II) complexes with an asymmetric bidentate Schiff-base ligand derived from furfurylamine

New asymmetric bidentate Schiff-base ligand (5-bromo-2-hydroxybenzyl-2-furylmethyl)imine, (HL), and its nickel(II) and copper(II) complexes with the general composition ML2 (M = Ni (1 )a nd Cu (2)), were prepared. The ligand and the metal complexes were characterized by elemental analysis, FT-IR, and UV-Vis spectroscopy. In addition, 1 H-NMR and X-ray powder diffraction (XRD) were employed for characterization of ligand and metal complexes, respectively. Thermogravimetric analysis (TGA) of the ligand and metal complexes revealed the thermal stability and decomposition pattern of the species.

Synthesis and Characterization of Transition Metal Complexes with

The Schiff bases namely MIMFMA, MIMTMA and MIPMA have been prepared by reacting 3-amino-5-methyl isoxazole with 5-methyl furan-2-carboxyaldehyde, 5-methyl thiphene-2-carboxaldehyde and pyridine-2-carboxaldehyde. The Cu(II), Ni(II), Co(II), Zn(II) and VO(IV) have been prepared by reacting metal chlorides with those Schiff bases in an alchololic medium. The complexes are electrolytes in DMSO. These have been characterized by using elemental analysis, IR, UV-VIS, 1H, 13C, mass spectra, magnetic susceptibility, conductance measurements and thermo gravimetric studies. The complexes were found to have composition ML2. On basis of elemental and spectral studies, six coordinated geometry is assigned for these complexes. The Schiff bases act as neutral and bidentate and coordinate through the azomethine nitrogen and furfural oxygen, thiophene sulphur and pyridine nitrogen, respectively. The synthesized ligands and their metal complexes were screened against bacteria and fungi. The activity data show that the metal complexes are more potent than the parent Schiff bases. Keywords; Schiff bases; Transition metal complexes; Spectral studies; Antimicrobial studies. © 2010 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved. DOI: 10.3329/jsr.v2i1.2732 J. Sci. Res. 2 (1), 114-126 (2010)

Synthesis, Characterization and Biological Activities of Cu(II), Co(II), Ni(II), Mn(II) and Fe(III) Complexes with Schiff Base Derived from 3‐(4‐Chlorophenoxymethyl)‐4‐amino‐5‐mercapto‐1,2,4‐triazole

Coordination complexes of Cu(II),Co(II), Ni(II), Mn(II) and Fe(III)with Schiff bases derived from 3‐(4‐chlorophenoxymethyl)‐4‐amino‐5‐mercapto‐1, 2, 4‐triazole and substituted aldehydes have been synthesized. The complexes were characterized by elemental analysis, conductivity measurements, magnetic susceptibility data, electronic, IR, ESR and 1H NMR spectral data. On the basis spectroscopic studies, the Schiff base is monobasic bidentate ligand having the composition ML2(2H2O) Where M = Cu(II), Co(II), Ni(II) ,Mn(II), ML2(H2O)Cl Where M = Fe(III). Various physicochemical data suggest a six coordinated octahedral geometry for Cu(II),Co(II), Ni(II), Mn(II) and Fe(III) complexes. The antibacterial activities of ligand and its complexes were screened by cup plate method.

Extraction of cobalt (II) and nickel (II) by a solvent impregnated resin containing bis(2,4,4-trimethylpentyl)monothiophosphinic acid

In the present work, studies have been conducted on the equilibrium distribution of cobalt (II) and nickel (II) between aqueous hydrochloric solution and macromolecular resin impregnated with bis(2,4,4-trimethylpentyl)monothiophosphinic acid (Cyanex302, HL). Effects of extraction time, pH values, metal ion concentration, and temperature were investigated. Analysis of the results shows that the extraction of the two metal ions can be explained assuming the formation of metal complexes in the resin phase with a general composition ML2. An extraction reaction is proposed and the equilibrium constants of the complexes were determined. The Freundlich isotherm and thermodynamic quantities, i.e., ΔG, ΔH and ΔS were also obtained. Both of the extraction reactions of cobalt (II) and nickel (II) are endothermic ones. The efficiency of the resin in the separation of cobalt (II) and nickel (II) is provided according to the separation factors. Under the experimental conditions employed, pH50 values for cobalt (II) and nickel (II) are 3.76, 5.01, respectively. The logarithmic value of separation factor was calculated as 2.50.

Complexes of Some 3d-Metal Salts with N,N-Dimethylhydrazide of 4-Nitrobenzoic Acid

The [M(HL)2(H2O)2]X2 complexes were synthesized (M = Mn(II), Co(II), Ni(II), Cu(II), Zn; X = CH3COO–, Cl–, BF4–) that incorporate bidentately coordinated molecules of N,N-dimethylhydrazide of 4-nitrobenzoic acid (HL). The latter molecules chelate the metal atom through the carbonyl O atom and the N atom of dimethylamino group. The square-planar complexes of Cu and Ni with deprotonated form of a ligand with composition ML2 were also isolated. The synthesized complexes were studied by IR, electronic and EPR spectroscopies, and by cyclic voltammetry.

Co(II), Ni(II) and Cu(II) Complexes with 1-(4-Hydroxyphenyl)-1H-1,2,4-Triazole

New complexes of Co(II), Ni(II), and Cu(II) with 1-(4-hydroxyphenyl)-1H-1,2,4-triazole (L) of the composition ML2(H2O)2(NO3)2 · nH2O (M = Co(II), n = 3; M = Ni(II), n = 0; M = Cu(II), n = 0) were synthesized and studied by photoelectron and IR spectroscopy, magnetochemistry, thermogravimetry, and X-ray powder diffraction analysis. The type of μeff(T) relationship suggests that paramagnetic centers in the Co(II) chloride and Cu(II) nitrate and bromide complexes are involved in antiferromagnetic exchange interactions. The exchange energy values were estimated by the molecular field method.

1,2-Bis(2-benzimidazolyl)-1,2-ethanediol, a chiral, tridentate, facially coordinating ligand

The ligand 1,2-bis(1H-benzimidazol-2-yl)-1,2-ethanediol, 1, and its methylated derivative 2 are readily synthesized from tartaric acid, and act as chiral, facially coordinating tridentate ligands, forming complexes of composition ML2 with octahedral transition metals. The copper(II) complexes show distorted 4 + 2 coordination with benzimidazoles occupying the equatorial sites and alcohol functions weakly binding in the axial sites. Nickel(II) complexes in three different states of protonation show regular octahedral geometry with the alcohols mutually cis. Deprotonation of the coordinated alcohol produces little structural change but the monodeprotonated complex forms a hydrogen bonded dimer. Magnetic measurements show the hydrogen bonded bridge to offer a pathway for weak antiferromagnetic coupling. UV-Visible spectroscopy shows the ligand to have a field intermediate between water and pyridine. The diastereoselectivity of complexation depends on the geometry: nickel(II) shows a weak preference for the homochiral complex, whereas copper(II) forms almost exclusively homochiral complexes.

CHARACTERIZATION AND EVALUATION OF LEVEXTREL EXTRACTION CHROMATOGRAPHIC RESINS FOR TRACE METAL SEPARATION SCHEMES IN AUTOMATIC WATER QUALITY CONTROL SYSTEMS.

ABSTRACT This paper presents the results of the selective removal of Zn(II) from Cu(II), Cd(II), Ni(II) and Pb(II) using ‘Extraction Chromatographic Resins’ Lewatit TP80T84, which contains dK2,4,4-trimethylpentyl)pbosphinic acid as active component. The extraction and selectivity patterns of the resin were obtained from the metal distribution coefficients as a fiinction of pH. Experimental data of Pb(II), Ni(II) and other natural water occurring metal ions, such as Ca(II), were analyzed graphically and numerically in order to describe the metal extraction reactions. Analysis of the results showed that the extraction of these metal ions can be explained assuming the formation of metal complexes in the resin phase with a general composition ML2(q 3HL)q, where q takes different values depending on the metal studied. Finally the efficiency of the resin in the selective removal of Zn(II) from the toxic heavy metal group Cu(T±), Cd(II), Ni(II) and Pb(II) were evaluated.of divalent metal ions (Zn(II), Cu(II), Cd(n), Ni(II), Pb(n)). Concerning the extraction selectivity of Lewatit TP80784 resins versus Zn(II), Cu(II)( Cd(n), Ca(n), Pb(n) and Ni(II), no differences have been found in comparison with the selectivity of this extractant in organic solvents (36). The results of the numerical treatment indicate that the extraction of Pb(n) and Ni(II) can be explained by assuming the formation of PbL2(HL2 and NiL2(HL)2. However, the extraction of Ca(II) can be explained assuming the formation of two species CaL2 and Ca(NO3)L|The analysis of the separation factors indicates that Lewatit TP80784 allows a quantitative separation of Zn(II) from Cd(II), Ni(II) and Pb(II) with ApHso greater that 2 and quasi-quantitative separations (90-95%) from Cu(II)|The results obtained in the extraction of Zn(IT), Cu(H), Cd(II), Ni(II), and Pb(n) from water samples in column experiments are very satisfactory, and the sytem will be used on-line in a multicomponent spectrophotometric method for the monitoring of low levels of toxic metal ions in surface waters.

SOLVENT IMPREGNATED RESINS CONTAINING DI(2-ETHYL-HEXYL)PHOSPHORIC ACID.II. STUDY OF THE DISTRIBUTION EQUILIBRIA OF Zn(II), Cu(II) AND Cd(II).

ABSTRACT The extraction of Zn(II), Cu(II) and Cd(II) from nitrate solutions at 0.1 M ionic strength by impregnated resins containing di(2-ethylhexyl)phosphoric acid has been studied at 25 °C. The distribution coefficient was determined as a function of both pH and extractant concentration in the resin phase. The data were analyzed graphically using the slope analysis method, and numerically using the program LETAGROP-DISTR. The composition of the extracted species in the resin phase has been determined. Analysis of the results showed that the extraction of these metal ions can be explained assuming the formation of metal complexes in the resin phase with a general composition ML2(HL) q where q takes different values depending on the metal. An extraction reaction is proposed and the extraction constants of these species are given. Finally, a comparison between the extraction of Zn(II), Cu(II) and Cd(II) by di(2-ethylhexyl)phosphoric acid into Amberlite XAD2 and the extraction using organic solvents has bee...

Study of the thermal dissociation of processes of nickel(II) and cobalt(II) β-diketonate adducts

Thermal dissociation processes ofβ-diketonate adducts with the composition ML2 · 2B (L = acetylacetone and its substituted derivatives;M = Ni, Co;B = H2O, BuNH2CH3OH, Py, NH3) were investigated. Kinetics of dissociation were studied in a flow reactor. For dehydration processes a compensation relationship is observed (lgA=E+b), demonstrating analogous mechanisms.A semi-quantitative series of the thermodynamic stabilities of the dihydrates is obtained from experimental data at quasi-equilibrium conditions (Q-derivatograph).

Co(II), Ni(II), Cu(II), Pd(II) and Pt(II) Complexes of Deprotonated Form of Thiosemicarbazones

Abstract Bis-chelates of Co(II), Ni(II), Cu(II), Pd(II) and Pt(II) with the thiol form of propiophenone or butyrophenone thiosemicarbazones have been synthesised and characterised by elemental analysis, magnetic moments, electronic and electron spin resonance spectral studies. All the complexes are found to have composition ML2, where M[dbnd]Co(II), Ni(II), Cu(II), Pd(II) or Pt(II) and L[dbnd]deprotonated thiosemicarbazones of propiophenone (PTSC) or butyrophenone (BTSC). The Co(II) and Cu(II) complexes are paramagnetic and may have polymeric octahedral and square planar geometries. The Ni(II), Pd(II) and Pt(II) complexes are diamagnetic and presumably have square planar geometry. Pyridine adducts (ML2.2Py) of Ni(II) and Cu(II) complexes have also been prepared and characterised.