Synthesis, characterization, theoretical calculations and catalase-like activity of mixed ligand complexes derived from alanine and 2-acetylpyridine

Mixed ligand complexes [M(2-AP)(Ala)Clx · mH2O]nH2O, where (M = CoII, NiII, CrIII and FeIII, 2-AP = 2-acetylpyridine, Ala = alanine, x = 2–3, m = 0–1 and n = 3–5] are synthesized and characterized by elemental analysis, FTIR, UV/Vis., MS, TG, measurements and semi-empirical calculations ZINDO/1 and PM3. The results suggest an octahedral geometry for all isolated complexes. FTIR spectra show that alanine coordinates to the metal ions as a neutral unidentate through the amino nitrogen where 2-acetylpyridine coordinates to the metal ion in a bidentate manner through carbonyl oxygen and pyridyl nitrogen. Semi-empirical calculations have been used to study the molecular geometry and the harmonic vibrational spectra with the purpose to assist the experimental assignment of the complexes. The Fe complex showed significant activity as a catalase-like model.