Syntheses of Coordination Compounds of (±)-2-Amino-3-(4-Hydroxyphenyl)Propionic Acid, Mixed Ligand Complexes and Their Biological Activities

Coordination compounds of (±)-2-amino-3-(4-hydroxyphenyl) propionic acid and their mixed ligand complexes with 1,10-phenantroline were synthesized, characterized using electronic and infrared spectral analyses and magnetic susceptibility. The compounds were evaluated for antimicrobial and antioxidant activities. Four different assays were applied for evaluating antioxidant capacity of the compounds. The results obtained indicated a diametric square planar geometry for both cobalt (±)-2-amino-3-(4-hydroxyphenyl) propionic acid complex and its mixed ligand complex. It was suggested that for the binary cobalt(II) complex, the phenolic substituent coordinated with neighbouring central metal ions. However, for the ternary cobalt(II) complex it was suggested it was deprotonated. Octahedral geometry was proposed for both copper complexes. Square planar geometry was indicated for the nickel (±)-2-amino-3-(4-hydroxyphenyl) propionic acid complex and a mixture of square planar and octahedral geometry for the nickel mixed ligand complex. The cobalt mixed ligand complex elicited the highest activity for all the antioxidant assays. In most cases the binary complexes exhibited better antimicrobial activities relative to their ternary counterparts.