Syntheses, Spectral Characterization, and Antimicrobial Studies on the Coordination Compounds of Metal Ions with Schiff Base Containing Both Aliphatic and Aromatic Hydrazide Moieties

An EtOH solution of 3-ketobutanehydrazide and salicylhydrazide on refluxing in equimolar ratio forms the corresponding Schiff base, LH 3 ( 1 ). The latter reacts with Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Zr(OH) 2 (IV), MoO 2 (VI), and UO 2 (VI) ions in equimolar ratio and forms the corresponding coordination compounds, [M(LH)(MeOH) 3 ] ( 2 , M = Mn, Co, Ni), [Cu(LH)] 2 ( 3 ), [M′(LH)(MeOH)] ( 4 , M′ = Zn, Cd), [Zr(OH) 2 (LH)(MeOH) 2 ] ( 5 ), [MoO 2 (LH)(MeOH)] ( 6 ), and [UO 2 (LH)(MeOH)] ( 7 ). The coordination compounds have been characterized on the basis of elemental analyses, molar conductance, spectral (IR, reflectance, 1 H NMR, ESR) studies, and magnetic susceptibility measurements. They are nonelectrolytes in DMSO. The coordination compounds, except 3 , are monomers in diphenyl. They are active against gram-positive bacteria ( S. aureus, B. subtilis ), gram-negative bacteria ( E. coli, P. aeruginosa ), and yeast ( S. cerevisiae, C. albicans ). 1 acts as a dibasic tridentate ONO donor ligand in 2–7 coordinating through its both enolic O and azomethine N atoms. The coordination compounds 2 and 3 are paramagnetic, while rest of the compounds are diamagnetic. A square-planar structure to 3 , a tetrahedral structure to 4 , an octahedral structure to 2 , 6 , and 7 , and a pentagonal bipyramidal structure to 5 are proposed.