Synthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistry, 43:961–965, 2013
Copyright ꢀ Taylor & Francis Group, LLC
C
ISSN: 1553-3174 print / 1553-3182 online
DOI: 10.1080/15533174.2012.751609
Synthesis, Characterization, and Antibacterial Activity
of Nickel(II) Complexes With Schiff Bases
Yan Xiong
College of Chemical Engineering and Pharmacy, Jingchu University of Technology, Jingmen, P. R. China
Aldrich and were used without further purification. Nickel(II)
perchlorate hexahydrate was prepared by the reaction of
nickel(II) carbonate basic tetrahydrate with perchloric acid in
distilled water. The micro analyses of the carbon, hydrogen
and nitrogen were performed on a model-240 Perkin-Elmer
elemental analyzer (Jingchu University of Technology, China).
The metal contents of the complexes were analyzed by EDTA
titration[6] after decomposing the organic matter with a mixture
of HClO4, H2SO4, and HNO3 (1:1.5:2.5). IR spectra were
recorded on a FT-IR Nicolet 400D spectrophotometer (Jingchu
University of Technology, China) as KBr pellets. Molar
conductances of the complexes were determined in DMF (ca.
10−4 M) at room temperature using a Jenway Model 4070
conductivity meter (Jingchu University of Technology, China).
Caution! Azido complexes of transition metal atoms contain-
ing organic ligands and perchlorate salts are potentially explo-
sive. Only a small amount of material should be prepared, and
they should be handled with care.
Two new Schiff base ligands, 2-bromo-6-[(3-cyclohexylami
nopropylimino)methyl]phenol (L1) and 2-bromo-6-[(2-ethylami
noethylimino)methyl]phenol (L2), and their mononuclear nickel
(II) complexes, 2[Ni(L1)2(N3)2]·EtOH·H2O (1) and [Ni(L2)2(NCS)2]
(2), have been prepared and characterized on the basis of elemen-
tal analyses, IR spectra, and single-crystal X-ray diffraction. The
complexes are mononuclear. The preliminary biological tests show
that the complexes have effective antibacterial activity.
Supplemental materials are available for this article. Go to the
publisher’s online edition of Synthesis and Reactivity in Inorganic,
Metal-Organic, and Nano-Metal Chemistry to view the supplemen-
tal file.
Keywords antibacterial activity, azide, nickel complex, Schiff base,
thiocyanate
INTRODUCTION
Schiff bases derived from the reaction of aromatic alde-
hydes and primary amines represent an important class of
organic ligands in coordination chemistry. The metal com-
plexes derived from Schiff bases have received considerable
attention in bioinorganic chemistry.[1–3] Schiff bases and their
metal complexes exhibit biological activity such as antibi-
otics, antiviral and antitumour agents, due to their specific
structures.[4,5] In this article, the structures and antibacterial ac-
tivities of two new Schiff bases, 2-bromo-6-[(3-cyclohexylami
nopropylimino)methyl]phenol (L1) and 2-bromo-6-[(2-ethyl
aminoethylimino)methyl]phenol (L2), and their mononuclear
nickel(II) complexes, 2[Ni(L1)2(N3)2]·EtOH·H2O (1) and
[Ni(L2)2(NCS)2] (2), are reported.
Preparation of the Schiff Bases
For L1: 3-Bromosalicylaldehyde (2.01 g, 10 mmol) and N-
cyclohexylpropane-1,3-diamine (1.56 g, 10 mmol) were mixed
in ethanol (30 mL). The mixture was refluxed for 1 h, and
then allowed to cool to room temperature. The resulting yel-
low microcrystals were collected and dried in air. Yield: 2.71 g
(80%). Anal. Calcd. (%) for C16H23BrN2O: C, 56.6; H, 6.8;
N, 8.3. Found (%): C, 56.4; H, 6.9; N, 8.2. L2 was pre-
pared by the same method as described for L1, with N-
cyclohexylpropane-1,3-diamine replaced by N-ethylethane-1,2-
diamine (0.88 g, 10 mmol). Yield: 1.35 g (50%). Anal. Calcd.
(%) for C11H15BrN2O: C, 48.7; H, 5.6; N, 10.3. Found (%): C,
48.6; H, 5.5; N, 10.3%.
EXPERIMENTAL
Materials and Methods
Preparation of the complex 1
3-Bromosalicylaldehyde,
mine, and N-ethylethane-1,2-diamine were purchased from
N-cyclohexylpropane-1,3-dia
A solution of nickel perchlorate hexahydrate (0.37 g, 1 mmol)
in ethanol (20 mL) was added to a solution of L1 (0.34 g, 1 mmol)
and sodium azide (0.06 g, 1 mmol) in ethanol (20 mL) and water
(5 mL). The mixture was refluxed for 30 min, and then allowed
to cool to room temperature. Green block-shaped single crystals
of 1 were formed by slow evaporation of the solution in air. The
crystals were isolated by filtration, and dried in air. Yield: 0.27 g
(61% based on L1). Anal. Calcd. (%) for C34H54Br2N10NiO4:
Received 25 April 2012; accepted 17 November 2012.
The author thanks Jingchu University of Technology for support.
Address correspondence to Y. Xiong, College of Chemical Engi-
neering and Pharmacy, Jingchu University of Technology, Jingmen
448000, P. R. China. E-mail: yanxiong088@163.com.
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