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Synthesis, Spectrophotometric and Biological
Activity of Nickel (II) and Copper (II) Complexes
with Schiff Base Derived from Acetylacetone and
Histidine.
H. N. Aliyu and A. S. Mohammed
Department of Chemistry Bayero University, P. M. B.
3011, Kano, Nigeria
*Corresponding Author E-mail:
hnuhu2000@yahoo.com
Accepted
18 June, 2012
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The reaction of the mixture of ethanolic solution of
acetylacetone and aqueous solution of histidine
yielded a Schiff base. The interaction of the Schiff
base in hot aqueous-methanol mixture and a metal
(II) chloride in ethanol gave the metal (II) Schiff
base complex. The complexes were characterized by
molar conductance measurement, infrared,
potentiometry, decomposition temperatures,
solubility and in vitro antimicrobial analysis. The
Schiff base is yellow, has melting point of 244oC
and percentage yield of 66%. The nickel (II) and
copper (II) complexes are green, have decomposition
temperatures of 166 and 160oC, and
percentage yield of 64.65 and 71.78%, respectively.
The Schiff base and the complexes are soluble in
water, DMSO and DMF, but are slightly soluble in
most organic solvents. Molar conductance measurement
of the complexes showed that they are
non-electrolyte. The infrared spectra of the Schiff
base showed a band at 1550 cm-1 assigned
to v(C=N) vibrational modes. Similar band
appeared in the spectra of the complex, but in the
lower frequency, confirming coordination of the
Schiff base to the respective metal (II) ions. The
bands in the spectra of the complex within 460 – 480
and at 625 - 630cm-1 are attributable to
v(M-N) and v(M-O) stretching
vibrations, respectively. The potentiometric
analysis of nickel (II) and copper (II) complex
compounds established 1:2, metal-ligand ratio. The
stability constant of the complexes determined are
6.29x 1018 and 1.59x1020. The
Schiff base showed no activity against Escheria
coli spp, Staphylococcus aureus,
Aspergillus niger and Candida Albican,
however, the complex compounds showed significant
activity against the organisms.
Keywords:
Acetylacetone, histidine, spectroscopy, conductance,
nickel (II), copper (II), complex, stability
constant, potentiometry and infrared.
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