Title: BEHAVIOUR OF N-(2-HYDROXYBENZYLIDENE)PYRAZINE-2-CARBOXAMIDE IN COMPLEXATION TOWARDS FE(II), CO(II), NI(II) AND CU(II) IONS: SYNTHESIS, SPECTRAL CHARACTERIZATION, MAGNETIC AND ANTIMICROBIAL PROPERTIES
Author(s): Festus Chioma and Okocha Ogechi
The new bidentate Schiﬀ base, N-(2-hydroxybenzylidene) pyrazine-2-carboxamide was synthesised from pyrazine-2-carboxamide and 2-hydroxybenzaldehydein alcoholic media. The Schiff base was reacted with FeSO4.7H2O, Co(NO3)2.6H2O, Ni(NO3)2.6H2O, Cu(NO3)2.3H2O to give the corresponding complexes of Fe(II), Co(II), Ni(II) and Cu(II). The synthesised ligand and its metal(II) complexes were characterised by melting point, FTIR, Uv-vis, molar conductance and magnetic susceptibility measurements. The observed shifts in FTIR spectral bands of the complexes with regards to the metal free ligand corroborates coordination of the Schiﬀbase with the metal ions through the phenolic oxygen and imine nitrogen atoms. The low values of molar conductivity in dimethylsulphoxide (DMSO) confirmed the non-electrolytic nature of the complexes, while the proposed molecular formulas of [M(L)2(H2O)2]⋅nH2O and [M(L)2(H2O)2], indicative of six coordinate octahedral geometry for Fe(II) and Ni(II)complexes; and four coordinate tetrahedral/square planar geometries for Co(II) and Cu(II) were consistent with the data of the elemental, spectral, magnetic and percentage metal analyses. Also, analytical and spectral resultsconfirmed 2L:1M stoichiometryfor the complexes. The synthesised compounds were evaluated for antimicrobial activities and found to be active against the bacteria and fungi organisms.
Keywords: Antimicrobial agents, pyrazine-2-carboxamide, bidentate Schiff base, octahedral