 |
ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 55, Number 6
JKCSEZ 55(6)
December 20, 2011 |
|
| |
Title |
Synthesis and Spectroscopic Characterization of Manganese(II), Iron(III) and Cobalt(III) Complexes of Macrocyclic Ligand. Potential of Cobalt(III) Complex in Biological Activity
|
Author |
Abdou S El Tabl*, Mohamad M E Shakdofa, Ahmed M A El Seidy |
Keywords |
Macrocyclic complexes, Spectral studies, magnetism,60Co-γ-rays on metal complexes and DNA
|
Abstract |
A new series of manganese(II), iron(III) and cobalt(III) complexes of 14-membered macrocyclic ligand, (3,6, 10,13,16,19-hexaazabicyclo[6.6.6]icosane-1,8-diamine) have been prepared and characterized by elemental analyses, IR, UVVIS, 1H- and 13C- NMR spectra, magnetic susceptibilities, conductivities, and ESR measurements. Molar conductance measurements in DMF solution indicate that the complexes are electrolytes. The ESR spectrum for cobalt(III) complex in CD3OD+10%D2O after exposure to 60Co-γ-rays at 77 K using a 0.2217 M rad h-1 vicrad source showed g⊥>g||>ge, indicating that, the unpaired electron site is mainly present in the dz2 orbital with covalent bond character. In this case, the ligand hyperfine tensors are nearly collinear with γ-tensors, so there is no major tendency to bend. Therefore, little extra delocalization via the ring lobe of the dz2 orbital occurs. However, the ESR spectrum in solid state after exposure to 60Co-γ-rays at 77 K showed g||>g⊥>ge, indicating that, the unpaired electron site is mainly present in the dx2-y2 ground state as the resulting spectrum contains a large number of randomly oriented molecules provided that, the principle directions of g and A tensors. Manganese (II) complex 2, [H12LMn]Cl4.2H2O, showed six isotropic lines characteristic to an unpaired electron interacting with a nucleus of spin 5/2, however, iron(III) complex 3, [H12LFe]Cl5.H2O, showed spectrum of a high spin 57Fe (I=1/2), d5 configuration. The geometry of these complexes was supported by elemental analyses, IR, electronic and ESR spectral studies. Complex 1 showed exploitation in reducing the amount of electron adducts formed in DNA during irradiation with low radiation products.
|
Page |
919 - 925 |
Full Text |
PDF
|
|
|
