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Vinodkumar, C. R.; Nair, M. R. Gopinathan; Radhakrishnan, P. K.

doi:10.1023/a:1010120909987

Cited by 55 publications

(15 citation statements)

References 16 publications

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“…From the obtained data, the following remarks can be made: The ∆S * values for the complexes are found to be negative. This indicates that the activated complex is more ordered than the reactants and/or the reactions are slow The negative values of ∆H * mean that the decomposition processes are exothermic. The positive values of ∆G * for the investigated complexes reveal increases significant for the subsequently decomposition stages due to the increasing values of T∆S * from one step to another which override the values of ∆H *.…”

Section: Resultsmentioning

confidence: 88%

Ni(II) and Cu(II) complexes with ONNO asymmetric tetradentate Schiff base ligand: synthesis, spectroscopic characterization, theoretical calculations, DNA interaction and antimicrobial studies

Abdel‐Rahman

Abu‐Dief

Moustafa

et al. 2016

Applied Organom Chemis

137

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A novel Schiff base, namely Z‐3‐((2‐((E)‐(2‐hydroxynaphthyl)methylene)amino)‐5‐nitrophenylimino)‐1,3‐dihydroindin‐2‐one, was synthesized from the condensation of 2‐hydroxy‐1‐naphthaldehyde and isatin with 4‐nitro‐o‐phenylenediamine. It was structurally characterized on the basis of 1H NMR, 13C NMR and infrared spectra and elemental analyses. In addition, Ni(II) and Cu(II) complexes of the Schiff base ligand were prepared. The nature of bonding and the stereochemistry of the investigated complexes were elucidated using several techniques, including elemental analysis (C, H, N), Fourier transform infrared and electronic spectroscopies and molar conductivity. The thermal behaviours of the complexes were studied and kinetic–thermodynamic parameters were determined using the Coats–Redfern method. Density functional theory calculations at the B3LYP/6‐311G++ (d, p) level of theory were carried out to explain the equilibrium geometry of the ligand. The optimized geometry parameters of the complexes were evaluated using LANL2DZ basis set. The total energy of highest occupied and lowest unoccupied molecular orbitals, Mullikan atomic charges, dipole moment and orientation are discussed. Moreover, the interaction of the metal complexes with calf thymus DNA (CT‐DNA) was explored using electronic spectra, viscosity measurements and gel electrophoresis. The experimental evidence indicated that the two complexes could strongly bind to CT‐DNA via an intercalation mechanism. The intrinsic binding constants of the investigated Ni(II) and Cu(II) complexes with CT‐DNA were 1.02 × 106 and 2.15 × 106 M−1, respectively, which are higher than that of the standard ethidium bromide. Furthermore, the bio‐efficacy of the ligand and its complexes was examined in vitro against the growth of bacteria and fungi to evaluate the antimicrobial potential. Based on the obtained results, the prepared complexes have promise for use as drugs. Copyright © 2016 John Wiley & Sons, Ltd.

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Section: Resultsmentioning

confidence: 88%

Ni(II) and Cu(II) complexes with ONNO asymmetric tetradentate Schiff base ligand: synthesis, spectroscopic characterization, theoretical calculations, DNA interaction and antimicrobial studies

Abdel‐Rahman

Abu‐Dief

Moustafa

et al. 2016

Applied Organom Chemis

137

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“…∆S* values for complexes were found to be positive. This reveals that the activated complex is less ordered than the reactants and/or the reactions are fast . ∆G* values increase in a sufficiently great or important way for the subsequently decomposition stages due to increasing T∆S* values of one step to another which override ∆H*values.…”

Section: Resultsmentioning

confidence: 99%

Characterization and thermal studies of nano‐synthesized Mn(II), Co(II), Ni(II) and Cu(II) complexes with adipohydrazone ligand as new promising antimicrobial and antitumor agents

Gaber

Khedr

Elsharkawy

2017

Applied Organom Chemis

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New seven complexes of N 1 ,N 6 -bis((2-hydroxynaphthalin-1-yl)methinyl)) adipohydrazone (H 2 L) with MnCl 2 •4H 2 O, CoCl 2 •6H 2 O, NiCl 2 •6H 2 O, CuCl 2 •2H 2 O, Cu(NO 3 ) 2 •3H 2 O, CuSO 4 •5H 2 O, and Cu(OAc) 2 •2H 2 O have beenprepared and characterized by the aid of elemental and thermal analyses, spectra (FT-IR, 1 H NMR, MS, UV-Vis, ESR, X-ray powder diffraction), molar conductance and magnetic moment measurements. The XRD results unambiguously confirmed the nano-sized particles of the complexes. The results showed that H 2 L behaves as dibasic tetra-dentate ligand towards the metal ions of interest. The low molar conductance values revealed the non-electrolytic nature for the chelates. The magnetic moment data, UV-Vis and ESR spectra denoted the formation of octahedral geometries for Mn(II) and Ni(II) complexes, whereas Co(II), Cu(II) complexes exhibited tetrahedral arrangement. The activation parameters for the thermal decomposition stages were calculated from TGA curves using Coats-Redfern and Horowitz-Metzger methods. The obtained data were confirmed by 3-D molecular modeling of the ligand and some complexes. The investigated compounds were screened for their antimicrobial activities against different types of organisms and antitumor activities towards human liver Carcinoma (HEPG2) cell to access their potential chemotherapeutic use. The free ligand (H 2 L) exhibited a weak inhibition of cell viability with IC 50 of 11.80 μg/ml, complexes 4, 6 and 7 showed a moderate activity with IC 50 of 5.56, 7.71 and 5.67 μg/ml, whereas complexes 1, 2, 3, and 5 displayed a strong anticancer activity with IC 50 of 4.65, 3.97, 3.30 and 4.84 μg/ml, compared with IC 50 value of 4.73 μg/ml for the doxorubicin (standard cytotoxin drug).

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“…In many cases the change of E or A with β is not monotonous. In spite of the last almost 20 years of observations, in recent papers [19][20][21][22][23] values of kinetic parameters obtained through the analysis of only one α = α(T ) curve, recorded at a given heating rate, are reported.…”

Section: Introductionmentioning

confidence: 99%

Some methodological problems concerning nonisothermal kinetic analysis of heterogeneous solid–gas reactions

Budrugeac

Segal

2001

Int J of Chemical Kinetics

140

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Isoconversional methods, those using only one curve α = α(T ) (α is the conversion degree and T is the temperature), and invariant kinetic parameter method were applied to estimate the kinetic parameters from the following nonisothermal data: (1) simulated TG curves for a single reaction; (2) TG curves for thermal degradation of PVC; and (3) TG curves for the dehydration of CaC 2 O 4 ·H 2 O. The results obtained by applying various methods for the same system are compared and discussed. Finally, a procedure of kinetic analysis is suggested. Its application could lead to kinetic parameter values that can be used to predict either α = α(t) curves for other heating rates or α = α(T ) curves for isothermal conditions.

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Untitled

Cited by 55 publications

References 16 publications

Ni(II) and Cu(II) complexes with ONNO asymmetric tetradentate Schiff base ligand: synthesis, spectroscopic characterization, theoretical calculations, DNA interaction and antimicrobial studies

Ni(II) and Cu(II) complexes with ONNO asymmetric tetradentate Schiff base ligand: synthesis, spectroscopic characterization, theoretical calculations, DNA interaction and antimicrobial studies

Characterization and thermal studies of nano‐synthesized Mn(II), Co(II), Ni(II) and Cu(II) complexes with adipohydrazone ligand as new promising antimicrobial and antitumor agents

Some methodological problems concerning nonisothermal kinetic analysis of heterogeneous solid–gas reactions

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