Structural, spectral, thermal and biological studies on 2-oxo-N′-((4-oxo-4H-chromen-3-yl)methylene)-2-(phenylamino)acetohydrazide (H2L) and its metal complexes

A new series of metal complexes formed by the reaction of 2-oxo-N′-((4-oxo-4H-chromen-3-yl)methylene)-2-(phenylamino)acetohydrazide(H2L) and Cu(II), Co(II), Ni(II), Cd(II), Zn(II), Hg(II) and U(VI)O22+ ions. The isolated complexes have been characterized by elemental analyses, spectral (IR, UV–visible and 1H NMR) as well as magnetic and thermal measurements. The data revealed that the ligand acts as neutral ON or ONO as well as mononegative ONO. On the basis of magnetic and electronic spectral data an octahedral geometry for the Co(II), Cu(II) and U(VI)O2 complexes, a tetrahedral structure for the Ni(II), Cd(II), Zn(II) and Hg(II) complexes have been proposed. The bond length, bond angle, HOMO, LUMO, dipole moment and charges on the atoms have been calculated to confirm the geometry of the ligand and the investigated complexes. Also, kinetic parameters were determined for each thermal degradation stage of some complexes using Coats–Redfern and Horowitz-Metzger methods. Moreover, the ligand and its complexes were screened against Bacillus thuringiensis (Bt) as Gram positive bacteria and Pseudomonas aeuroginosa (Pa) Gram negative bacteria using the inhibitory zone diameter.

► Preparation of ligand and its metal complexes. ► Characterization of prepared complexes. ► Spectral, thermal, magnetic and ESR studies. ► Animicrobial study.