scholarly journals Formation constant of lanthanide metal ion with substituted thiazole Schiff base in mixed solvent media and thermodynamic parameter

2020 ◽  
Vol 8 (2) ◽  
pp. 07-10
Author(s):  
BN Muthal
Keyword(s):  
Schiff Base ◽  
Thermodynamic Parameter ◽  
Metal Ion ◽  
Formation Constant ◽  
Mixed Solvent ◽  
Lanthanide Metal

Efficient Preconcentration of Cu2+, Zn2+ and Fe3+ with an Agarose-Schiff Base Sorbent

2007 ◽  
Vol 72 (7) ◽  
pp. 908-916 ◽  
Author(s):  
Payman Hashemi ◽  
Hatam Hassanvand ◽  
Hossain Naeimi
Keyword(s):  
Schiff Base ◽  
Metal Ions ◽  
Metal Ion ◽  
Good Accuracy ◽  
Kinetic Studies ◽  
Sample Volume ◽  
Effects Of Ph ◽  
Glass Column ◽  
High Concentrations ◽  
Ph Range

Sorption and preconcentration of Cu2+, Zn2+ and Fe3+ on a salen-type Schiff base, 2,2'- [ethane-1,2-diylbis(nitrilomethylidyne)]bis(2-methylphenol), chemically immobilized on a highly crosslinked agarose support, were studied. Kinetic studies showed higher sorption rates of Cu2+ and Fe3+ in comparison with Zn2+. Half-times (t1/2) of 31, 106 and 58 s were obtained for sorption of Cu2+, Zn2+ and Fe3+ by the sorbent, respectively. Effects of pH, eluent concentration and volume, ionic strength, buffer concentration, sample volume and interferences on the recovery of the metal ions were investigated. A 5-ml portion of 0.4 M HCl solution was sufficient for quantitative elution of the metal ions from 0.5 ml of the sorbent packed in a 6.5 mm i.d. glass column. Quantitative recoveries were obtained in a pH range 5.5-6.5 for all the analytes. The volumes to be concentrated exceeding 500 ml, ionic strengths as high as 0.5 mol l-1, and acetate buffer concentrations up to 0.3 mol l-1 for Zn2+ and 0.4 mol l-1 for Cu2+ and Fe3+ did not have any significant effect on the recoveries. The system tolerated relatively high concentrations of diverse ions. Preconcentration factors up to 100 and detection limits of 0.31, 0.16 and 1.73 μg l-1 were obtained for Cu2+, Zn2+ and Fe3+, respectively, for their determination by a flame AAS instrument. The method was successfully applied to the metal ion determinations in several river water samples with good accuracy.

scholarly journals Characterization of the two 5-aminolaevulinic acid binding sites, the A- and P-sites, of 5-aminolaevulinic acid dehydratase from Escherichia coli

1995 ◽  
Vol 305 (1) ◽  
pp. 151-158 ◽  
Author(s):  
P Spencer ◽  
P M Jordan
Keyword(s):  
Schiff Base ◽  
Binding Sites ◽  
Metal Ion ◽  
Substrate Binding ◽  
Aminolaevulinic Acid ◽  
Acid Dehydratase ◽  
Carboxylate Groups ◽  
Catalytic Metal ◽  
A Site ◽  
Aminolaevulinic Acid Dehydratase

Experiments are described in which the individual properties of the two 5-aminolaevulinic acid (ALA) binding sites, the A-site and the P-site, of 5-aminolaevulinic acid dehydratase (ALAD) have been investigated. The ALA binding affinity at the A-site is greatly enhanced (at least 10-fold) on the binding of the catalytic metal ion (bound at the alpha-site). The nature of the catalytic metal ion, Mg2+ or Zn2+, also gave major variations in the substrate Km, P-site affinity for ALA, the effect of potassium and phosphate ions and the pH-dependence of substrate binding. Modification of the P-site by reaction of the enzyme-substrate Schiff base with NaBH4 and analysis of the reduced adduct by electro-spray mass spectrometry indicated a maximum of 1 mol of substrate incorporated/mol of subunit, correlating with a linear loss of enzyme activity. The reduced Schiff-base adduct was used to investigate substrate binding at the A-site by using rate-of-dialysis analysis. The affinity for ALA at the A-site of Mg alpha Zn beta ALAD was found to determine the Km for the reaction and was pH-dependent, with its affinity increasing from 1 mM at pH 6 to 70 microM at pH 8.5. The affinity of ALA at the P-site of Zn alpha An beta ALAD is proposed to limit the Km at pH values above 7, since the measured Kd for ALA at the A-site in 45 microM Tris, pH 8, was well below the observed Km (600 microM) under the same conditions. The amino group of the ALA molecule bound at the P-site was identified as a critical binding component for the A-site, explaining why ALA binding to ALAD is ordered, with the P-site ALA binding first. Structural requirements for ALA binding at the A- and P-sites have been identified: the P-site requires the carbonyl and carboxylate groups, whereas the A-site requires the amino, carbonyl and carboxylate groups of the substrate.

Chromogenic ‘naked eye’ and fluorogenic ‘turn on’ sensor for mercury metal ion using thiophene-based Schiff base

RSC Advances ◽  
2015 ◽  
Vol 5 (81) ◽  
pp. 65731-65738 ◽  
Author(s):  
Divya Singhal ◽  
Neha Gupta ◽  
Ashok Kumar Singh
Keyword(s):  
Schiff Base ◽  
Binding Affinity ◽  
Metal Ion ◽  
Limit Of Detection ◽  
Electrochemical Behaviour ◽  
Naked Eye ◽  
Turn On

2-((3-Methylthiophen-2-yl)methyleneamino)benzenethiol (Probe 1) is selective for Hg2+. The binding affinity of Hg2+ with Probe 1 was confirmed by DFT and electrochemical behaviour. The limit of detection was 20 μM with 2 : 1 stoichiometry of 1 + Hg2+ complex.

scholarly journals Ni(II) Dimers of NNO Donor Tridentate Reduced Schiff Base Ligands as Alkali Metal Ion Capturing Agents: Syntheses, Crystal Structures and Magnetic Properties

2018 ◽  
Vol 4 (4) ◽  
pp. 51 ◽  
Author(s):  
Monotosh Mondal ◽  
Maharudra Chakraborty ◽  
Michael G. B. Drew ◽  
Ashutosh Ghosh
Keyword(s):  
Schiff Base ◽  
Metal Ion ◽  
Magnetic Measurements ◽  
Dft Method ◽  
Distorted Octahedral Geometry ◽  
Schiff Base Ligands ◽  
Reduced Schiff Base ◽  
Ferromagnetic Interactions ◽  
Experimental Values ◽  
Reduced Schiff Base Ligands

Three trinuclear Ni(II)-Na(I) complexes,[Ni2(L1)2NaCl3(H2O)]·H2O (1), [Ni2(L2)2NaCl3(H2O)] (2), and [Ni2(L3)2NaCl3(OC4H10)] (3) have been synthesized using three different NNO donor tridentate reduced Schiff base ligands, HL1= 2-[(3-methylamino-propylamino)-methyl]-phenol, HL2= 2-[(3-methylamino-propylamino)-methyl]-4-chloro-phenol, and HL3= 2-[(3-methylamino-propylamino)-methyl]-6-methoxy-phenol that had been structurally characterized. Among these complexes, 1 and 2 are isostructural in which dinuclearNi(II) units act as metalloligands to bind Na(I) ions via phenoxido and chlorido bridges. The Na(I) atom is five-coordinated, and the Ni(II) atom possesses hexacordinated distorted octahedral geometry. In contrast, in complex 3, two -OMe groups from the dinuclear Ni(II) unit also coordinate to Na(I) to make its geometry heptacordinated pentagonal bipyramidal. The magnetic measurements of complexes 1–3 indicate ferromagnetic interactions between dimeric Ni(II) units with J = 3.97 cm−1, 4.66 cm−1, and 5.50 cm−1for 1–3, respectively, as is expected from their low phenoxido bridging angles (89.32°, 89.39°, and 87.32° for 1–3, respectively). The J values have been calculated by broken symmetry DFT method and found to be in good agreement with the experimental values.

Mix and match: templating chiral Schiff base ligands to suit the needs of the metal ion

2010 ◽  
Vol 39 (22) ◽  
pp. 5332 ◽  
Author(s):  
Edwin C. Constable ◽  
Guoqi Zhang ◽  
Catherine E. Housecroft ◽  
Jennifer A. Zampese
Keyword(s):  
Schiff Base ◽  
Metal Ion ◽  
Schiff Base Ligands ◽  
Chiral Schiff Base ◽  
Mix And Match

scholarly journals Synthesis and characterization of N, O-donor Schiff base capped ZnS NPs as a sensor for fluorescence selective detection of Fe 3+, Cr 2+ and Cd 2+ ions

2018 ◽  
Vol 4 (4) ◽  
pp. 151-162
Author(s):  
Dasari Ayodhya ◽  
Guttena Veerabhadram
Keyword(s):  
Schiff Base ◽  
Quantum Confinement ◽  
Metal Ion ◽  
Quantum Confinement Effect ◽  
Precipitation Method ◽  
Donor Ligand ◽  
Zinc Sulfide Nanoparticles ◽  
Co Precipitation ◽  
Selective Sensor

We report the simple synthesis of zinc sulfide nanoparticles (ZnSNPs) by a co-precipitation method using Schiff base, (2-[(4-methoxy-phenylimino)-methyl]-4-nitro phenol) as a capping agent. Here, Schiff base is also used as N, O-donor ligand to control the morphology of NPs and fluorescence interactions. The formation of ZnSNPs and their optical, structural, thermal properties and morphologies were studied by means of UV–vis DRS, fluorescence, FTIR, XRD, SEM, TEM, zeta potential and TGA. The optical properties and quantum confinement effect of the products were confirmed by means of spectroscopic measurements. XRD and TEM image shows that the synthesized ZnSNPs have cubic structures with a diameter of about less than 10 nm. The prepared ZnSNPs exhibited as a selective probe detection of Fe3+, Cr2+ and Cd2+ ions by fluorometrically and the emission band which disappears in the presence of increasing concentrations of Fe3+, Cr2+ and Cd2+ ions. Based on the fluorescence quenching of the NPs in the presence of metal ion of interest, the feasibility of their determinations was examined according to the Stern-Volmer equation. Our work suggested that Schiff base capped ZnSNPs could be a potential selective sensor in the detection of heavy metal ions.

scholarly journals Nickel(II)-Based Building Blocks with Schiff Base Derivatives: Experimental Insights and DFT Calculations

Molecules ◽  
2021 ◽  
Vol 26 (17) ◽  
pp. 5316
Author(s):  
Néstor Novoa ◽  
Carolina Manzur ◽  
Thierry Roisnel ◽  
Samia Kahlal ◽  
Jean-Yves Saillard ◽  
...  
Keyword(s):  
Schiff Base ◽  
General Formula ◽  
Metal Ion ◽  
Density Functional ◽  
Building Blocks ◽  
Switching Behavior ◽  
Planar Geometry ◽  
Centrosymmetric Dimer ◽  
Square Planar ◽  
Tridentate Schiff Base

We have recently reported a series of neutral square planar tridentate Schiff base (L) complexes of the general formula [(L)M(py)], showing relatively high first-order hyperpolarizabilities and NLO redox switching behavior. In the present study, new members of this family of compounds have been prepared with the objective to investigate their potential as building blocks in the on-demand construction of D-π-A push–pull systems. Namely, ternary nickel(II) building blocks of general formula [(LA/D)Ni(4-pyX)] (4–7), where LA/D stands for an electron accepting or donating dianionic O,N,O-tridentate Schiff base ligand resulting from the monocondensation of 2-aminophenol or its 4-substituted nitro derivative and β-diketones R-C(=O)CH2C(=O)CH3 (R = methyl, anisyl, ferrocenyl), and 4-pyX is 4-iodopyridine or 4-ethynylpyridine, were synthesized and isolated in 60–78% yields. Unexpectedly, the Sonogashira cross-coupling reaction between the 4-iodopyridine derivative 6 and 4-ethynylpyridine led to the formation of the bis(4-pyridyl) acetylene bridged centrosymmetric dimer [{(LD)Ni}2(µ2-py-C≡C-py)] (8). Complexes 4–8 were characterized by elemental analysis, FT-IR and NMR spectroscopy, single crystal X-ray diffraction and computational methods. In each compound, the four-coordinate Ni(II) metal ion adopts a square planar geometry with two nitrogen and two oxygen atoms as donors occupying trans positions. In 8, the Ni…Ni separation is of 13.62(14) Å. Experimental results were proved and explained theoretically exploiting Density Functional Theory calculations.

scholarly journals Synthesis and Spectral Analysis of Some Metal Ions Complexes with Mixed Ligands of Schiff Base and 1, 10-Phenanthroline

2017 ◽  
Vol 14 (1) ◽  
pp. 135-147
Author(s):  
Baghdad Science Journal
Keyword(s):  
Schiff Base ◽  
Metal Ions ◽  
Metal Complexes ◽  
Mass Spectrometer ◽  
Schiff Base Ligand ◽  
Metal Ion ◽  
Molecular Structures ◽  
Spectroscopic Techniques ◽  
Metal Ion Complexes ◽  
Free Schiff Base

The free Schiff base ligand (HL1) is prepared by being mixed with the co-ligand 1, 10-phenanthroline (L2). The product then is reacted with metal ions: (Cr+3, Fe+3, Co+2, Ni+2, Cu+2 and Cd+2) to get new metal ion complexes. The ligand is prepared and its metal ion complexes are characterized by physic-chemical spectroscopic techniques such as: FT-IR, UV-Vis, spectra, mass spectrometer, molar conductivity, magnetic moment, metal content, chloride content and microanalysis (C.H.N) techniques. The results show the formation of the free Schiff base ligand (HL1). The fragments of the prepared free Schiff base ligand are identified by the mass spectrometer technique. All the analysis of ligand and its metal complexes are in good agreement with the theoretical values indicating the purity of Schiff base ligand and the metal complexes. From the above data, the molecular structures for all the metal complexes are proposed to be octahedral

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