Geometrical structures, thermal properties and spectroscopic studies of Schiff base complexes: Correlation between ionic radius of metal complexes and DNA binding

A novel series of transition metal complexes of Cu(II), Co(II), Ni(II), Mn(II) and Cd(II) were prepared from Schiff base derived from 4-aminoantipyrine and quinoline-2-carbaldehyde to give 4-((quinolin-2-yl)methyleneamino)-1,2-dihydro-2,3-dimethyl-1-phenylpyrazol-5-one (QMP). The structural features...

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Bibliographic Details
Published in:	Journal of molecular liquids Vol. 240; pp. 752 - 776
Main Authors:	Morgan, Sh.M., El-Sonbati, A.Z., Eissa, H.R.
Format:	Journal Article
Language:	English
Published:	Elsevier B.V 01-08-2017
Subjects:	Antimicrobial activity Geometrical structures Molecular docking Schiff base metal complexes Thermal analysis Thermodynamics parameters Geometrical structures Antimicrobial activity Thermal analysis Thermodynamics parameters Molecular docking Schiff base metal complexes
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Summary:	A novel series of transition metal complexes of Cu(II), Co(II), Ni(II), Mn(II) and Cd(II) were prepared from Schiff base derived from 4-aminoantipyrine and quinoline-2-carbaldehyde to give 4-((quinolin-2-yl)methyleneamino)-1,2-dihydro-2,3-dimethyl-1-phenylpyrazol-5-one (QMP). The structural features were derived from elemental analysis, mass spectroscopy, X-ray, IR, 1H NMR, electronic spectra, molar conductance magnetic susceptibility and thermogravimetric studies. On the basis of the studies the coordination sites were proven to be through oxygen of the ring CO and nitrogen of the azomethine (HCN) group. The thermodynamic parameters were calculated using Coats–Redfern and Horowitz–Metzger methods. From the values of the thermal activation energy of decomposition (Ea) of Schiff base (QMP) and its metal complexes (1–5), it was found that the Ea value for the complex (3) is higher compared to the other complexes. The Gibbs free energy of decomposition (ΔG⁎) for Schiff base (QMP) and its metal complexes is positive value which indicates that the processes are non-spontaneous. The interaction between Schiff base (QMP) and its metal complexes and calf thymus DNA shows hypochromism effect coupled with obvious bathochromic shift. From the values of binding constant (Kb) we noted that the highest value of Kb is belong complex (3) and these indicated that the Ni(II) is highly binding with CT-DNA and these due to the lower ionic radius. Furthermore, quantum chemical parameters of Schiff base and its complexes were calculated and discussed. The antimicrobial activity of Schiff base (QMP) and its M(II) complexes were studied and compared with the standard antibacterial and antifungal drugs. X-ray diffraction pattern of powder form and optimized structure of Schiff base. [Display omitted] •A series of M(II) complexes of Schiff base were prepared and characterized.•Quantum chemical parameters and kinetic parameters were calculated and discussed.•The XRD studies show that the ligand and its complexes have polycrystalline with crystal structure.
ISSN:	0167-7322 1873-3166
DOI:	10.1016/j.molliq.2017.05.114