Stability Constants and Antimicrobial Studies of Metal(II) Complexes with Cinnamaldehyde-(2-hydroxy benzylidene)hydrazide

Abstract

Synthesis and structural features of some bidentate Schiff base complexes of the type [M(NNO)₂] [where M = Cu²⁺, Ni²⁺, Co²⁺, Mn²⁺ and NNO = cinnamaldehyde-(2-hydroxy benzylidene)hydrazide] are reported. The ligand was derived by the condensation of cinnamaldehyde hydrazone with salicyaldehyde. These metal complexes were characterized by elemental analysis, molar conductance, magnetic momentum measurements, IR, ¹H NMR spectral data. An octahedral geometry was proposed for all metal complexes. Stability constants of these metal complexes were determined using a potentiometric method at constant ionic strength (0.1 m) at different temperature (25, 30, 35 ºC) in 50 % v/v ethanol-water mixture by calculating the values of η_A, η and P_L, has been found that ligand forms complexes in 1:2 ratio. Antimicrobial activities of ligand and its metal complexes were evaluated against strains- E. coli, Klebsiella, Enterococci and S. aureus. It has been found that metal complexes have higher activity than the parent ligand and their bio-potency are discussed.