Abstract

Synthesis, characterization, thermal behavior and biological activity of some L-histidine metal complexes

Author(s): Abdullah Sulaiman Al-Ayed

The L-histidine forming complexes of with Cr(III), Fe(III),Mn(II), Co(II), Ni(II) and Cu(II) of the type 1:1 and 1:2 (M:L) have been synthesized and characterized bymeans of elemental analysis, molar conductance, IR spectra, thermal analysis, UV-Vis spectra, magnetic moment and ESR spectra. The low molar conductance values suggest the non-electrolytic nature of these complexes. Spectroscopic and other analytical studies revealed a square planar geometry for copper complexes and octahedral geometry for the other complexes. The thermal behavior of these complexes indicated that the hydrated complexes loss water of hydration in first step followed by the loss of coordinated water and chloride immediately. The activation thermodynamic parameters, such asÄE*, ÄH*, ÄS*, and ÄG* are calculated using Coats–Redfern method. Antimicrobial activity of L-histidine and its complexes has been tested against different microorganisms.