Synthesis, spectral, photoluminescence, DFT studies and bioassay of new Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) complexes of 1-ethyl-4-hydroxy-3-(nitroacetyl) quinolin-2(1H)-one

Abstract

The complexation between 1-ethyl-4-hydroxy-3-(nitroacetyl)quinolin-2(1H)-one, H2L with iron(III), cobalt(II), nickel(II), copper(II) and zinc(II) has been accomplished. The structure of the resulting complexes has been elucidated through elemental analyses, FT-IR,1H NMR, electronic, mass spectra, powder XRD, and ESR spectral analyses, as well as magnetic susceptibility, molar conductance measurements and thermal analyses. The analytical and spectroscopic data show complexes of the general formula [(L)MX(H2O)m(EtOH)n]·yZ; where: M = Fe, Ni, Cu or Zn; X = NO3− or nil, m = 3 or 4, n = 1 or nil and Z = EtOH or H2O and y = 0.5, 1 or 2 and [(L)2Co (H2O)(EtOH)]·½ EtOH. The lower values of molar conductance indicate the non-electrolytic nature of these complexes, suggesting that the ligand behaves as a dibasic bidentate in all complexes except Co(II) complex, in which the ligand acts as monobasic bidentate. The shape of ESR spectrum of copper(II)complex revealed octahedral geometry. The XRD patterns for the ligand and its metal complexes indicate crystalline nature with nano particle sizes. Structural parameters of the ligand and its metal complexes were calculated on the basis of DFT level using Gaussian 09 and the data correlated with the experimental results. The photoluminescence (PL) properties of the ligand and its metal complexes were investigated the dispersion of the ligand‏ into silica matrix has been successfully used in developing latent fingerprint sensor on non-porous surfaces. The antimicrobial activity of the ligand and its complexes was studied against E. coli, P. vulgaris, S. aureus, K. pnemonia and C. albicans.These compounds were evaluated for their cytotoxic effect on Ehrlish Ascities Carcinoma cells lines (EAC). Among the tested compounds, Co(II) and Ni(II)- complexes exhibited more potent activity with an IC50 value of 12.5 and 15 μg/ml respectively, comparable to cisplatin.