&lt;b&gt;Studies on some VO(IV), Ni(II) and Cu(II) complexes of non-symmetrical tetradentate Schiff-bases&lt;/b&gt;

Osowole, Aderoju A.

doi:10.4314/bcse.v22i2.61288

Cited by 5 publications

(4 citation statements)

References 19 publications

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“…3H 2 O prepared in situ, showed a band at 525 nm which may be assigned to 2 A 1g → 2 B 1g and is consistent with a square-planar [19,20] or a distorted tetragonal [21] geometry for this complex. The NiL.H 2 O showed two bands at 430 and 590 nm assigned as 1 A 1g → 1 B 1g and 1 A 1g → 1 A 2g attributed to the presence of this complex in the square-planar structure [12,20,22] . As for the cobalt complex CoL 2 .H 2 O, three bands were observed at 513, 635 and 677nm respectively assignable to the 4 T 1g (F)→ 4 A 2g (F) and 4 T 1g (F)→ 4 T 2g (F) [23] transitions in an octahedral structure.…”

Section: Electronic Absorption Spectrasupporting

confidence: 57%

Comparative Study Between N,n'-Bis (Acetylacetone)-O-Phenylenediamine and (Monoacetylacetone)-O-Phenylenediamine Schiff Base Complexes

Soayed

Refaat

2013

J. Chil. Chem. Soc.

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Co(II) , Ni(II) and Cu(II) complexes formed from the Sciff base [ (2Z,4Z)-4-[(2-aminophenyl)imino-]pent-2-en-2-ol] , were prepared in situ and characterized on the basis of elemental analyses, magnetism, UV-vis., IR and ESR spectra . Thermal analyses of the complexes were studied in order to confirm the proposed structures and determine their thermal stability . Comparison between geometries, ESR and thermal studies obtained from direct condensation and in situ preparation of complexes were discussed. The in situ data show that the Schiff base form complexes with 1:1 (metal : ligand) stoichiometry with Cu(II) and Ni(II) ions compared to 2:1 (metal : ligand) formed from direct condensation between schiff base and metal ions. However, the Co(II) in situ complex formed 1:2 (metal: ligand ) stoichiometry. Square-planar geometry was suggested for the Cu(II) and Ni(II) in situ complexes, while, octahedral geometry was suggested for the Co(II) complex. The ESR spectrum of the in situ Cu(II) complex was isotropic to suggest a geometry involving grossly misaligned tetragonal axes .The thermal behavior of the complexes showed good agreement with the formulae suggested from the analytical data . Thermal decomposition of the complexes took place in several stages. The order of stability was [Cu L.(H 2 The thermodynamic parameters , energy of activation ∆ E * a , enthalpy of activation ∆H * , order of reaction n and entropy of activation ∆S * of the complexes were calculated. All the reactions were found to be first order. The high values of activation energies reveal the high stability of these complexes.

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Section: Electronic Absorption Spectrasupporting

confidence: 57%

Comparative Study Between N,n'-Bis (Acetylacetone)-O-Phenylenediamine and (Monoacetylacetone)-O-Phenylenediamine Schiff Base Complexes

Soayed

Refaat

2013

J. Chil. Chem. Soc.

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“…A d 8 system can only exhibit the absence of an unpaired electron (a diamagnetic property) if a square planar geometry has been adopted by the complex; hence, a subzero moment is recorded [42,43]. A magnetic moment of 2.90-3.30 BM is expected for an octahedral geometry and 3.20-4.10 BM is expected for a tetrahedral geometry for a nickel complex [44,45]. NiMDBz had a moment of 0.38 BM, while NiEDBz had a magnetic moment of 0.47 BM.…”

Section: Magnetic and Conductivitymentioning

confidence: 99%

Synthesis, Biological, and Quantum Chemical Studies of Zn(II) and Ni(II) Mixed-Ligand Complexes Derived from N,N-Disubstituted Dithiocarbamate and Benzoic Acid

Ekennia¹,

Onwudiwe

Osowole

et al. 2016

Journal of Chemistry

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Some mixed-ligand complexes of Zn(II) and Ni(II) derived from the sodium salt ofN-alkyl-N-phenyl dithiocarbamate and benzoic acid have been prepared. The complexes are represented as ZnMDBz, ZnEDBz, NiMDBz, and NiEDBz (MD:N-methyl-N-phenyl dithiocarbamate, ED:N-ethyl-N-phenyl dithiocarbamate, and Bz: benzoate); and their coordination behavior was characterized on the basis of elemental analyses, IR, electronic spectra, magnetic and conductivity measurements, and quantum chemical calculations. The magnetic moment measurement and electronic spectra were in agreement with the four proposed coordinate geometries for nickel and zinc complexes and were corroborated by the theoretical quantum chemical calculations. The quantum chemically derived thermodynamics parameters revealed that the formation ofN-methyl-N-phenyl dithiocarbamate complexes is more thermodynamically favourable than that of theN-ethyl-N-phenyl dithiocarbamate complexes. The bioefficacy of the mixed-ligand complexes examined against different microbes showed moderate to high activity against the test microbes. The anti-inflammatory and antioxidant studies of the metal complexes showed that the ethyl substituted dithiocarbamate complexes exhibited better anti-inflammatory and antioxidant properties than the methyl substituted dithiocarbamate complexes.

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“…d-d bands at 540, 670 nm which were assigned to spin allowed transitions of 3 A 2 (F) → 3 T 1 (F) and 3 A 2 (F) → 3 T 1 (P) [36] [37]. The magnetic moment of 0.83 BM indicated two unpaired electrons per nickel ion, further validates a square planar geometry [40].…”

Section: Electronic Spectra and Magnetic Momentmentioning

confidence: 80%

Syntheses, Characterization, Antimicrobial Activity and Extraction Studies of Tetraaza Macrocyclic/Linear Schiff Bases Derived from Benzene-1,4-Dicarboxaldehyde and Their Coordination Compounds

Aiyelabola¹,

Jordaan²,

Otto³

et al. 2021

ABC

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Non-template [2 + 2] condensation of benzene-1,4-dicarboxaldehyde with two diamines: ethane-1,2-diamine and propane-1,2-diamine was carried out to give Ligands 1 and 2. Additionally, template [1 + 2] condensation of benzene-1,4-dicarboxaldehyde with ethane-1,2-diamine and propane-1,2-diamine were also carried out to give Ligands 3 and 4. These were characterized using 1 H and 13 C NMR, UV-Vis and infra-red spectroscopy and mass spectrometry. Coordination compounds of each ligand were further synthesized using Ni(II) and Cu(II) ions. They were characterized by Uv-vis, infrared spectroscopy, mass spectrometry, magnetic susceptibility and energy dispersion X-ray spectroscopy EDX. The ligands and complexes were further analyzed for their antimicrobial activities and extraction efficiency. The results obtained suggested that tetraaza macrocyclic and linear compounds were obtained for [2 + 2] and [1 + 2] condensation reactions respectively. Coordination compounds of the macrocyclic ligand yielded octahedral geometry for Ni(II) and Cu(II) complexes of Ligand 1 and square planar geometry for Ni(II) and Cu(II) complexes of Ligand 2. On the other hand square planar geometry was proposed for coordination compounds of Ligand 3 and 4 exception for the Ni(II) complex of Ligand 3. All ligands coordinated to the metal ion in a tetradentate fashion. In some cases chelation enhanced the antimicrobial activity of some of the ligands. The results further showed that Ligands 1-4 effectively How to cite this paper: Aiyelabola, T.,

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<b>Studies on some VO(IV), Ni(II) and Cu(II) complexes of non-symmetrical tetradentate Schiff-bases</b>

Cited by 5 publications

References 19 publications

Comparative Study Between N,n'-Bis (Acetylacetone)-O-Phenylenediamine and (Monoacetylacetone)-O-Phenylenediamine Schiff Base Complexes

Comparative Study Between N,n'-Bis (Acetylacetone)-O-Phenylenediamine and (Monoacetylacetone)-O-Phenylenediamine Schiff Base Complexes

Synthesis, Biological, and Quantum Chemical Studies of Zn(II) and Ni(II) Mixed-Ligand Complexes Derived from N,N-Disubstituted Dithiocarbamate and Benzoic Acid

Syntheses, Characterization, Antimicrobial Activity and Extraction Studies of Tetraaza Macrocyclic/Linear Schiff Bases Derived from Benzene-1,4-Dicarboxaldehyde and Their Coordination Compounds

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