Synthesis, spectroscopic determination, and antimicrobial studies of Schiff base derived from 4-phenylthiosemicarbazide with 2-acetylpyridine and its Co(II) and Ni(II) complexes

Abstract

Condensation of 4-phenylthiosemicarbazide with 2-acetylpyridine in (1:1 molar ratio) eth
anol produced Schiff base (2)-N-phenyl-2-[1-(pyridin-2-yl)ethylidene]hydrazine-1-carboth
ioamide (Acetylpyridine-4-phenylthiosemicarbazone). Interaction of the Schiff base with 
each of Co(II) and Ni(II) metal salts in (2:1 molar ratio) ethanol produced the Schiff base 
metal(II) complexes. The Schiff base and its Co(II) and Ni(II) complexes were characterized 
based on melting point/decomposition temperature, solubility, magnetic susceptibility, 
infrared spectra, molar conductance measurements, elemental, and gravimetric analyses. 
The Co(II) and Ni(II) metal complexes show moderate values of decomposition tempera
tures The Schiff base and the complexes were soluble in some common organic solvents. 
Infrared spectral data of the Schiff base and its complexes, indicated coordination of the 
Schiff base to the metal(II) ion via azomethine nitrogen. The effective magnetic moment of 
the Co(II) and Ni(II) complexes suggested an octahedral geometry. The molar conductance 
values of the complexes show that the complexes are electrolytes. The results of the ele
mental analysis of the ligand and its complexes are in good agreement with the calculated 
values, suggesting a 1:2 (metal-ligand) ratio. Antimicrobial screenings of the ligand and its 
complexes were conducted against Gram-positive (Staphylococcus aureus) and two Gram
negative (Salmonella typhii, and Escherichia coli) bacteria species. Also, three fungi mainly 
(Candida albicans, Mucus indicus, and Aspergillus flavus) were used. The results showed 
that both the ligand and the complexes are active against the species used.