Synthesis, spectral and thermo-kinetics explorations of Schiff-base derived metal complexes

2020 ◽  
Vol 18 (1) ◽  
pp. 1304-1315
Author(s):  
Naushad Ahmad ◽  
Manawwer Alam ◽  
Rizwan Wahab ◽  
Mukhtar Ahmed ◽  
Ashfaq Ahmad
Keyword(s):  
Schiff Base ◽  
Metal Complexes ◽  
Thermal Analyses ◽  
Nitrogen Atmosphere ◽  
Molar Conductance ◽  
Spectral Parameters ◽  
Exponential Factor ◽  
One Step ◽  
Ft Ir ◽  
Thermodynamic Equations

AbstractSchiff-base ligand, 2,6-bis(benzimino)-4-phenyl-1,3,5-triazine (L), and its transition metal complexes of Co(ii), Ni(ii), and Cu(ii) were synthesized by refluxing the reaction mixture and its analytical, spectral, and thermogravimetric characteristics were explored by various techniques: AAS, FT-IR, UV-vis, TG-DTG, CHNS/O, and VSM. It was observed that all the metal containing complexes are non-electrolytic, mononuclear, and paramagnetic in nature, confirmed by the molar conductance and magnetic susceptibility measurements. Optical spectral data were used to investigate the geometrical and spectral parameters of [Co(L)(ac)2], [Ni(L)(ac)2], [Cu(L)(ac)2], [Cu(L)(acac)2], and [Cu(L)(fmc)2] complexes. Simultaneous thermal analyses (TG-DTG) in nitrogen atmosphere reveal that the ligand decomposes in one step, [Co(L)(ac)2], [Ni(L)(ac)2], and [Cu(L) (ac)2] complexes are decomposed in three steps, whereas [Cu(L)(acac)2] and [Cu(L) (fmc)2] are decomposed in five and two steps, respectively. In addition, activation energy (Ea) and pre-exponential factor (ln A) were evaluated by TG-DTG decomposition steps of compounds using the Coats–Redfern formula. Enthalpy (∆H), entropy (∆S), and Gibbs free energy (∆G) of the as-prepared metal complexes were also speculated by various thermodynamic equations.

scholarly journals Synthesis, characterization, thermal, theoretical and antimicrobial studies of Schiff base ligand and its Co(II) and Cu(II) complexes

2020 ◽  
Vol 85 (2) ◽  
pp. 215-225 ◽  
Author(s):  
Palaniswamy Venkittapuram ◽  
Mahalakshmi Dhandapani ◽  
Jonekirubavathy Suyambulingam ◽  
Chitra Subramanian
Keyword(s):  
Schiff Base ◽  
Metal Complexes ◽  
Schiff Base Ligand ◽  
Bacterial Species ◽  
Thermal Analyses ◽  
Fungal Species ◽  
Basis Sets ◽  
Chloride Salt ◽  
Antimicrobial Studies ◽  
Ft Ir

A Schiff base ligand L was synthesized by condensation of 1,2-diaminoethane with creatinine. The reaction of the ligand with metal chloride salt gives Co(II) and Cu(II) complexes. The synthesized ligand and its metal complexes were characterized by elemental analysis, FT-IR, NMR, UV?Vis, conductivity and magnetic susceptibility measurements as well as thermal analyses. Based on spectral data, tetrahedral geometries have been proposed for the Co(II) and Cu(II) complexes. The molar conductivity data show that the complexes are non-electrolytic in nature. In DFT studies, the geometry of the Schiff base ligand and its Co(II) and Cu(II) complexes were fully optimized using the B3LYP functional together with 6-31g(d,p) and LANL2DZ basis sets. The ligand and its metal complexes were tested against four bacterial species and two fungal species. The results revealed that the metal complexes are more potent against the microbes than the parent ligand.

scholarly journals Synthesis, Characterization and Antibacterial Activity of Schiff Base, 4-Chloro-2-{(E)-[(4-Fluorophenyl)imino]methyl}phenol Metal (II) Complexes

2020 ◽  
Vol 2020 ◽  
pp. 1-8 ◽  
Author(s):  
F. K. Ommenya ◽  
E. A. Nyawade ◽  
D. M. Andala ◽  
J. Kinyua
Keyword(s):  
Antibacterial Activity ◽  
Schiff Base ◽  
Metal Complexes ◽  
Elemental Analysis ◽  
Schiff Base Ligand ◽  
Condensation Reaction ◽  
Molar Conductance ◽  
Diffusion Method ◽  
Elemental Analysis Data ◽  
Ft Ir

A new series of Mn (II), Co (II), Ni (II), Cu (II), and Zn (II) complexes of the Schiff base ligand, 4-chloro-2-{(E)-[(4-fluorophenyl)imino]methyl}phenol (C13H9ClFNO), was synthesized in a methanolic medium. The Schiff base was derived from the condensation reaction of 5-chlorosalicylaldehyde and 4-fluoroaniline at room temperature. Elemental analysis, FT-IR, UV-Vis, and NMR spectral data, molar conductance measurements, and melting points were used to characterize the Schiff base and the metal complexes. From the elemental analysis data, the metal complexes formed had the general formulae [M(L)2(H2O)2], where L = Schiff base ligand (C13H9ClFNO) and M = Mn, Co, Ni, Cu, and Zn. On the basis of FT-IR, electronic spectra, and NMR data, “O” and “N” donor atoms of the Schiff base ligand participated in coordination with the metal (II) ions, and thus, a six coordinated octahedral geometry for all these complexes was proposed. Molar conductance studies on the complexes indicated they were nonelectrolytic in nature. The Schiff base ligand and its metal (II) complexes were tested in vitro to evaluate their bactericidal activity against Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) and Gram-positive bacteria (Bacillus subtilis and Staphylococcus typhi) using the disc diffusion method. The antibacterial evaluation results revealed that the metal (II) complexes exhibited higher antibacterial activity than the free Schiff base ligand.

scholarly journals Synthesis, Spectral and Antimicrobial Studies of Some Co(II), Ni(II) and Cu(II) Complexes Containing 2-Thiophenecarboxaldehyde Moiety

2012 ◽  
Vol 9 (3) ◽  
pp. 1113-1121 ◽  
Author(s):  
A. P. Mishra ◽  
A. Tiwari ◽  
S. K. Gupta ◽  
Rajendra Jain
Keyword(s):  
Schiff Base ◽  
Metal Complexes ◽  
Antimicrobial Agents ◽  
Analytical Data ◽  
Molar Conductance ◽  
E Coli ◽  
Antimicrobial Studies ◽  
Degradation Pattern ◽  
Ft Ir ◽  
Schiff Base Metal Complexes

Some new Schiff base metal complexes of Co(II), Ni(II) and Cu(II) derived from 3-chloro-4-fluoroaniline (HL1) and 4-fluoroaniline (HL2) with 2-thiophenecarboxaldehyde have been synthesized and characterized by elemental analysis, FT-IR, FAB-mass, molar conductance, electronic spectra, ESR and magnetic susceptibility. The complexes exhibit coordination number 4 or 6. The complexes are colored and stable in air. Analytical data revealed that all the complexes exhibited 1:2 (metal: ligand) ratio. FAB-mass data show degradation pattern of the complexes. The Schiff base and metal complexes show a good activity against the bacteria;B. subtilis,E. coliandS. aureusand fungiA. niger,A. flavusandC. albicans. The antimicrobial results also indicate that the metal complexes are better antimicrobial agents as compared to the Schiff bases.

scholarly journals Spectral Investigation andIn VitroAntibacterial Evaluation of NiIIand CuIIComplexes of Schiff Base Derived from Amoxicillin andα-Formylthiophene (αft)

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Narendra Kumar Chaudhary ◽  
Parashuram Mishra
Keyword(s):  
Schiff Base ◽  
Metal Complexes ◽  
Pathogenic Bacteria ◽  
Sensitivity Study ◽  
Molar Conductance ◽  
Planar Geometry ◽  
Field Calculation ◽  
Orthorhombic Crystal ◽  
Standard Drug ◽  
Ft Ir

Two new metal complexes of general formula M(Haαft)2[M =NiIIandCuII] of asymmetrical Schiff base ligand (HL = Haαft) derived from amoxicillin andα-formylthiophene have been prepared and characterized by various physicochemical and spectral techniques. Molar conductance measurement indicates nonelectrolytic nature of the metal complexes. FT-IR spectral study reveals the ligation of metal ions at two different nitrogen [NN] donor sites of Haαft. FT-IR and electronic absorption spectral evidences suggest distorted tetrahedral and square planar geometry forCuIIandNiIIcomplexes, respectively. The structure optimization by molecular mechanics (MM) force field calculation through ArgusLab 4.0.1 version software also supports the concerned geometry of the complexes. The cell dimensions as suggested by XRPD study,a(6.753 Å),b(13.904 Å),c(20.122 Å),α(142.76°),β(106.580°), andγ(72.4343°) forCuIIanda(24.2547 Å),b(6.6371 Å),c(5.5047 Å) (α=β=γ= 90°) forNiIIcomplexes, are in good agreement with their triclinic and orthorhombic crystal systems. Particle size calculation by Scherrer’s formula indicates nanocrystalline nature of the complexes. The antibacterial sensitivity study suggests promising activities of Haαft (Ligand) and M(Haαft)2complexes against four clinical pathogenic bacteria, namely,E. coli,P. vulgaris,P. aeruginosa, andS. aureus, though being less active than the standard drug amikacin.

scholarly journals Synthesis, Characterization and Antimicrobial Studies of N1-[(1E)-1-(2-Hydroxyphenyl) ethylidene]-2-oxo-2H-chromene-3-carbohydrazide and its Metal Complexes

2009 ◽  
Vol 6 (3) ◽  
pp. 615-624 ◽  
Author(s):  
K. Siddappa ◽  
K. Mallikarjun ◽  
Tukaram Reddy ◽  
M. Mallikarjun ◽  
C. V. Reddy ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Magnetic Susceptibility ◽  
Schiff Base ◽  
Metal Complexes ◽  
Molar Conductance ◽  
Tetrahedral Geometry ◽  
H Nmr ◽  
Antimicrobial Studies ◽  
Mononuclear Complexes ◽  
Uv Visible

A new complexes of the type ML, MʹL and M″L [where M=Cu(II), Co(II), Ni(II) and Mn(II), Mʹ=Fe(III) and M″=Zn(II), Cd(II) and Hg(II) and L=N1-[(1E)-1-(2-hydroxyphenyl)ethylidene]-2-oxo-2H-chromene- 3-carbohydrazide (HL)] Schiff base have been synthesized and characterized by elemental analysis, magnetic susceptibility, molar conductance, IR,1H NMR, UV-Visible and ESR data. The studies indicate the HL acts as doubly monodentate bridge for metal ions and form mononuclear complexes. The complexes Ni(II), Co(II), Cu(II) Mn(II) and Fe(III) complexes are found to be octahedral, where as Zn(II), Cd(II) and Hg(II) complexes are four coordinated with tetrahedral geometry. The synthesized ligand and its metal complexes were screened for their antimicrobial activity.

scholarly journals Polydentate Schiff Base Ligands and Their La(III) Complexes: Synthesis, Characterization, Antibacterial, Thermal, and Electrochemical Properties

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Ali E. Şabik ◽  
Muharrem Karabörk ◽  
Gökhan Ceyhan ◽  
Mehmet Tümer ◽  
Metin Dığrak
Keyword(s):  
Antimicrobial Activity ◽  
Schiff Base ◽  
Electrochemical Properties ◽  
Antimicrobial Activities ◽  
Nitrogen Atmosphere ◽  
Spectroscopic Methods ◽  
Schiff Base Ligands ◽  
One Step ◽  
The One ◽  
Reversible Transfer

We synthesized the Schiff base ligands H2L1–H2L4 and their La(III) complexes and characterized them by the analytical and spectroscopic methods. We investigated their electrochemical and antimicrobial activity properties. The electrochemical properties of the ligands H2L1–H2L4 and their La(III) complexes were studied at the different scan rates (100 and 200 mV), different pH ranges (), and in the different solvents. The electrooxidation of the Schiff base ligands involves a reversible transfer of two electrons and two protons in solutions of pH up to 5.5, in agreement with the one-step two-electron mechanism. In solutions of pH higher than 5.5, the process of electrooxidation reaction of the Schiff base ligands and their La(III) complexes follows an ECi mechanism. The antimicrobial activities of the ligands and their complexes were studied. The thermal properties of the metal complexes were studied under nitrogen atmosphere in the range of temperature 20–1000°C.

scholarly journals Metal Complexes of a Novel Schiff Base Based on Penicillin: Characterization, Molecular Modeling, and Antibacterial Activity Study

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Narendra Kumar Chaudhary ◽  
Parashuram Mishra
Keyword(s):  
Thermal Stability ◽  
Antibacterial Activity ◽  
Schiff Base ◽  
Metal Complexes ◽  
Parent Drug ◽  
Molar Conductance ◽  
Kinetic Properties ◽  
Field Calculation ◽  
Tetrahedral Geometry

A novel Schiff base ligand of type HL was prepared by the condensation of amoxicillin trihydrate and nicotinaldehyde. The metal complexes of Co+2, Ni+2, Cu+2, and Zn+2 were characterized and investigated by physical and spectral techniques, namely, elemental analysis, melting point, conductivity, 1H NMR, IR, UV-Vis spectra, ESR, SEM, and mass spectrometry measurements. They were further analyzed by thermal technique (TGA/DTA) to gain better insight about the thermal stability and kinetic properties of the complexes. Thermal data revealed high thermal stability and nonspontaneous nature of the decomposition steps. The Coats-Redfern method was applied to extract thermodynamic parameters to explain the kinetic behavior. The molar conductance values were relatively low, showing their nonelectrolytic nature. The powder XRD pattern revealed amorphous nature except copper complex (1c) that crystallized in the triclinic crystal system. The EPR study strongly recommends the tetrahedral geometry of 1c. The structure optimization by MM force field calculation through ArgusLab 4.0.1 software program supports the concerned geometry of the complexes. The in vitro antibacterial activity of all the compounds, at their two different concentrations, was screened against four bacterial pathogens, namely, E. coli, P. vulgaris, K. pneumoniae, and S. aureus, and showed better activity compared to parent drug and control drug.

scholarly journals Microwave Synthesis, Spectral, Thermal and Antimicrobial Studies of Some Co(II), Ni(II) and Cu(II) Complexes Containing 2-Aminothiazole Moiety

2012 ◽  
Vol 9 (4) ◽  
pp. 1655-1666 ◽  
Author(s):  
A. P. Mishra ◽  
H. Purwar ◽  
Rajendra K. Jain ◽  
S. K. Gupta
Keyword(s):  
Electrical Conductivity ◽  
Schiff Base ◽  
Solid State ◽  
Metal Complexes ◽  
Analytical Data ◽  
Xrd Analysis ◽  
Lattice Parameter ◽  
Molar Conductance ◽  
Unit Cell ◽  
Antimicrobial Studies

Some new Schiff base metal complexes of Co(II), Ni(II) and Cu(II) derived from 4-chlorobenzylidene-2-aminothiazole (CAT) and 2-nitrobenzylidene-2-aminothiazole (NAT) have been synthesized by conventional as well as microwave methods. These compounds have been characterized by elemental analysis, FT-IR, FAB-mass, molar conductance, electronic spectra, ESR, magnetic susceptibility, thermal, electrical conductivity and XRD analysis. The complexes are coloured and stable in air. Analytical data revealed that all the complexes exhibited 1:2 (metal:ligand) ratio with coordination number 4 or 6. FAB-mass and thermal data show degradation pattern of the complexes. The thermal behavior of metal complexes shows that the hydrated complexes loses water molecules of hydration in the first step; followed by decomposition of ligand molecules in the subsequent steps. The crystal system, lattice parameter, unit cell volume and number of molecules in unit cell in the lattice of complexes have been determined by XRD analysis. XRD patterns indicate crystalline nature for the complexes. The solid state electrical conductivity of the metal complexes has also been measured. Solid state electrical conductivity studies reflect semiconducting nature of the complexes. The Schiff base and metal complexes show a good activity against the Gram-positive bacteria;Staphylococcus aureusand Gram-negative bacteria;Escherichia coliand fungiAspergillus nigerandCandida albicans.

scholarly journals Spectral, Magnetic and Biological Studie on Some Bivalent 3d Metal Complexes of Hydrazine Derived Schiff-Base Ligands

1997 ◽  
Vol 4 (2) ◽  
pp. 65-68 ◽  
Author(s):  
Zahid H. Chohan ◽  
Syed K. A. Sherazi
Keyword(s):  
Schiff Base ◽  
Metal Complexes ◽  
Elemental Analysis ◽  
Magnetic Moment ◽  
Bacterial Species ◽  
Biological Properties ◽  
Molar Conductance ◽  
Schiff Base Ligands ◽  
H Nmr ◽  
3D Metal Complexes

Metal(II) complexes of hydrazine derived Schiff-base ligands of the type M(L)2Cl2 where M = Co, Cu, Ni and Zn and L = L1 and L2 have been prepared and characterised by molar conductance, magnetic moment, elemental analysis and electronic, IR, H-NMR and C13 spectral data.The different modes of chelation of the ligands and their comparative biological properties against different bacterial species are reported.

scholarly journals Synthesis, Spectroscopy, Theoretical, and Electrochemical Studies of Zn(II), Cd(II), and Hg(II) Azide and Thiocyanate Complexes of a New Symmetric Schiff-Base Ligand

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Morteza Montazerozohori ◽  
Kimia Nozarian ◽  
Hamid Reza Ebrahimi
Keyword(s):  
Schiff Base ◽  
Metal Complexes ◽  
Schiff Base Ligand ◽  
Structural Parameters ◽  
Free Ligand ◽  
Basis Set ◽  
Cyclic Voltammograms ◽  
Hybrid Functional ◽  
Ft Ir ◽  
C Nmr

Synthesis of zinc(II)/cadmium(II)/mercury(II) thiocyanate and azide complexes of a new bidentate Schiff-base ligand (L) with general formula of MLX2(M = Zn(II), Cd(II), and Hg(II)) in ethanol solution at room temperature is reported. The ligand and metal complexes were characterized by using ultraviolet-visible (UV-visible), Fourier transform infrared (FT-IR),1H- and13C-NMR spectroscopy and physical characterization, CHN analysis, and molar conductivity.1H- and13C-NMR spectra have been studied in DMSO-d6. The reasonable shifts of FT-IR and NMR spectral signals of the complexes with respect to the free ligand confirm well coordination of Schiff-base ligand and anions in an inner sphere coordination space. The conductivity measurements as well as spectral data indicated that the complexes are nonelectrolyte. Theoretical optimization on the structure of ligand and its complexes was performed at the Becke’s three-parameter hybrid functional (B3) with the nonlocal correlation of Lee-Yang-Parr (LYP) level of theory with double-zeta valence (LANL2DZ) basis set using GAUSSIAN 03 suite of program, and then some theoretical structural parameters such as bond lengths, bond angles, and torsion angles were obtained. Finally, electrochemical behavior of ligand and its complexes was investigated. Cyclic voltammograms of metal complexes showed considerable changes with respect to free ligand.

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