Spectroscopic characterization of Cu(II), Ni(II), Co(II) complexes, and nano copper complex bearing a new S, O, N-donor chelating ligand. 3D modeling studies, antimicrobial, antitumor, and catalytic activities

Abstract

A new tridentate hydrazone ligand (HL), its Co(II), Ni(II), Cu(II) complexes (in 1:1, 1:2 molar ratios of metal to ligand), and the mixed-ligand Co(II), Ni(II), Cu(II) complexes of the ligand HL, with 8-HQ in 1:1:1 (M:L:8-HQ) stoichiometry, in addition to a nano Cu(II) complex have been synthesized and characterized using physical, analytical and spectral methods. Octahedral geometry was assigned for all investigated complexes except Cu(II) complex 1 which exhibited square planar arrangement. The TGA results suggested the thermal stability of the current complexes. The XRD data indicated that the particles of Cu(II) complex 2 were situated in nano-scale range. Furthemore, the SEM and TEM images of the nano Cu(II) complex 2 showed spherical and sheet-shaped particles with an average size of 48 nm. The geometries of the metal complexes were optimized with respect to the energy taking the 6-311G(p,d) basis set in Gaussian 09 W program in gaseous phase by DFT. The data obtained revealed that all metal complexes are more reactive than the free ligand HL, and the Cu(II) complex 1 has the highest chemical reactivity. The antimicrobial activity study illustrated enhancement in activity of the free ligand upon complex formation., and the Cu(II) complex 1 may be considered as promising antibacterial agent, and as promising antifungal agent. The results of antitumor activity study revealed an inhibition of HepG-2 cell growth for the ligand HL, with enhancement in activity upon complexation, and the Cu(II) complex 1 exhibited the highest cytotoxic activity. The phenoxazinone synthase activity study indicated the ability of both Cu(II) complexes 1 and 2 to catalyze the oxidative dehydrogenation of 2-aminophenol (OAPH) to 2-aminophenoxazine-3-one (APX) under atmospheric conditions and at room temperature.