Synthesis and Characterization of Ti(III), Cr(III), Mn(III) and Fe(III) Complexes Incorporating Tridentate Ono Donar Hydrazone Ligands

Abstract

New complexes of the Ti(III), Cr(III), Mn(III) and Fe(III) with hydrazones, derived from the condensation of 4-nitrobenzoylhydrazide with either 2-hydroxy-5-chloroacetophenone or 2-hydroxy-5-methylacetophenone, have been synthesized and characterized by elemental analyses, magnetic moment, electronic and infrared spectra and thermogravimetric analysis. Both ligands coordinated with metal ions in a tridentate dinegative fashion through their deprotonated phenolic-0, deprotonated enolic-O and imine nitrogen atoms. The thermal decomposition of ligands and complexes has been studied using non-isothermal thermogravimetry. Kinetic parameters such as activation energy, frequency factor, free energy change and entropy change of decomposition of complexes have been determined by employing the methods of Coats-Redfern and Horowitz-Metzger. The antibacterial and antifungal activities of the ligands and their complexes have been assessed by screening the compounds against £. coli, S. abong, S. aureus, P. arugineosa, B. subtilis, A. niger and C. albicans respectively. The measurements of the electrical conductivity of ligands and their metal complexes were carried out in the temperature range 308 -410 K in their compressed pellet form .The electrical activation energy values of the complexes were calculated from Arrhenius plots and lie in the range 0.368-0.759 eV. The complexes show a low value of conductance at room temperature; however their conductivities 225 Brought to you by | Western University Authenticated Download Date | 6/8/15 9:48 AM Vol. 29, No. 4, 2009 Synthesis and Characterization of Ti(III), Cr(lII), Mn(lll) increase as the temperature increases above 335K, indicating their semiconducting behaviour.

Synthesis of (E)-4-Methyl-2-((Phenethylimino (Phenyl)methyl)phenol and Its Transition Metal Complexes, Characterization and Electrical Conductivity Study of Complexes

“…In the low-temperature range, a slow increase in electrical conductivity and high-temperature range rapid increase with temperature has been observed. The activation energy (E a ) of HMBPE metal complexes obtained from plots was found in the range 0.106-0.311 eV and decrease in order Cu(II) > Cd(II) > Co(II) > Zn(II) > Mn(II) > Ni(II) 56,57 . Activation energy is the direct measure of the band gap of semiconductors, lowers the activation energy, the lower will be the band gap.…”