Electrochemical Study of the Mixed Ligand Complexes of Co(II) and Ni(II) with Acetylsalicylic Acid and Nicotinamide

The interaction of acetylsalicylic acid (aspirin, aspH) and nicotinamide (NA) with Co(II) and Ni(II) ions was investigated using square-wave and cyclic voltammetry techniques. In the presence of Ni(II)/Co(II),nicotinamide gave new peaks at -0.85V and soh.12 V, corresponding to the reduction of Ni(II)-nicotinamide(log β_1:2 =5.97) and Co(II)-nicotinamide (log β_1:2 =5.19) complexes, respectively. In the presence of Ni(II)/Co(II), acetylsalicylic acid gave new peaks at -0.91V and -1.19 V, respectively, corresponding to the reductionof Ni(II)-salicylate (log β_1:2 =8.48) and Co(II)-salicylate (log β_1:2 =8.14) complexes. In the presence of nicotinamide, Ni(II)-salicylate and Co(II)-salicylate form mixed ligand complexes, reducing at -0.78V (log β_1:2:2 =9.68) and -1.14V (log β_1:2:2 =8.64), respectively.