Physico-Chemical and SpectroscopicInvestigations of New Metallic Complexes withPhenylalanine as Ligand

摘要

The [Cu(L)_2]H_2O(1), [Co(L)_2H_2) and Zn(3) metallic complexeswith phenylalanine as ligand were synthesized in aqueous solution and characterized by meansof atomic absorption, elemental analysis, differential scanning calorimetry, FT—IR, UV—VIS andESR spectroscopies. The comparative analysis of the FT-IR spectra for the ligand and thecomplexes indicate the coordination of the metallic centre to the carboxylic oxygen atom and tothe nitrogen atom of the amino group. In the ligand spectrum the v_s(N-H) stretching vibrationappears splitted at 3078cm~(-1)and 3030cm~(-is shifted at 3320cm~(-3256cm~(-in the coppercomplex, at 3220cm~(-1)in the cobalt spectrum and at 3256cm~(-3334cm~(-for zinc complexproving the involvement of the — NH_2— group in the complex formation. The v_s(C=O) stretchingvibration emerge in the ligand spectrum at 1623cm' and appears to be shifted toward higherwave numbers with 4cm~(-1) and 10cm~(-1)for Cu and Co complexes with 9cm~(-toward lowerwave numbers for Zn complex. The niu π~ characteristic band in the UV spectra assigned to theC=O bond appear at 231= for phenylalanine and is shifted toward lower wave lengths in thecomplexes spectra proving the covalent nature of the metal-ligand bond. Powder ESR spectra atroom temperature are typically for monomeric species with pseudotetrahedral symmetry aroundthe copper ions and octahedral environment for the cobalt ion.