Synthesis, spectral and antimicrobial activity studies of o-aminoacetophenone o-hydroxybenzoylhydrazone complexes

Coordination compounds of Mn-II, Co-II, Ni-II, Cu-II, Zn-II, Cd-II and Hg-I I ions with o-aminoacetophenone o-hydroxybenzoylhydrazone (AAOHBH) were syn thesized and characterized by elemental analyses, molar conductivity, magne tic moments (at ca. 25 degrees C) and spectral (i.r., u.v., n.m.r. and m.s. ) studies. The i.r. spectra show that the ligand acts in a monovalent biden tate, neutral bidentate and/or neutral tridentate fashion, depending on the metal salt used and the reaction medium. Tetrahedral structures are propos ed for both Co-II and Ni-II complexes and square planar for Cu-II complexes on the basis of magnetic and spectral evidence. The complex formation in s olution was investigated potentiometrically and spectrophotometrically. Spe ctral studies in solution show that the ligand can be used for the microdet ermination of Co-II ion within a metal concentration up to 46.3 p.p.m. The electrical conductivity of AAOHBH and its metal complexes was determined. T he tendency of AAOHBH to form complexes with Co-II, Ni-II, (CuI)-I-I, Cd-II and Hg-II ions in 50% aqueous-dioxane was studied by pH measurements. The antimicrobiol activity of AAOHBH and its complexes derived from Co-II, Ni-II and Cu-II illustrates that the Ni-II complex seems to be inert toward s Escherichia coli and Bacillus subtilis. The antimicrobial activity of the Cu-II complex was higher against E. coli and lower against B. subtilis tha n the corresponding organic ligand. The Co-II complex has the same activity as the organic ligand against E. coli.