Co(II), Cd(II), Hg(II) and U(VI)O2 complexes of o-hydroxyacetophenone[N-(3-hydroxy-2-naphthoyl)] hydrazone: Physicochemical study, thermal studies and antimicrobial activity

Abstract The o -Hydroxy acetophenone [ N -(3-hydroxy-2-naphthoyl)] hydrazone (H 2 o -HAHNH) has been prepared and its structure is confirmed by elemental analysis, IR, 1 H NMR and 13 C NMR spectroscopy. It has been used to produce diverse complexes with Co(II), Cd(II), Hg(II) and U(VI)O 2 ions. The isolated complexes have been investigated by elemental analysis, magnetic measurements, molar conductivity, thermal (TG, DTG) and spectral ( 1 H NMR, 13 C NMR, IR, UV–visible, MS) studies. Infrared spectra suggested H 2 o -HAHNH acts as a bidentate and/or tridentate ligand. The electronic spectrum of [Co(H o -HAHNH) 2 ] complex as well as its magnetic moments suggesting octahedral geometry around Co(II) center. The TG analyses suggest high stability for most complexes followed by thermal decomposition in different steps. Moreover, the kinetic and thermodynamic parameters ( Ea , A , Δ H ∗ , Δ S ∗ and Δ G ∗ ) for the different decomposition steps of the [Co(H o -HAHNH) 2 ] and [Cd(H o -HAHNH) 2 ] complexes were calculated using the Coats–Redfern and Horowitz–Metzger methods. Moreover, the antibacterial and antifungal activities of the isolated compounds were studied using a wide spectrum of bacterial and fungal strains.