J. Chil. Chem. Soc., 57, Nº 3 (2012)
PREPARATION, SPECTROSCOPIC CHARACTERIZATION OF A NEW Cd(II) COMPLEX CONTAINING
TRIDENTATE NNO SCHIFF BASE DERIVED AND X-RAY CRYSTALLOGRAPHIC STRUCTURAL STUDY OF
3,4,5-TRIHYDROXYBENZOIC ACID[1-(PYRIDYL)-ETHYLIDENE]HYDRAZONE
ABEER A. ALHADI1, SHAYMA A. SHAKER2, *, NURA SULEIMAN G1, WAGEE A.
YEHYE1, HAPIPAH MOHD ALI1
1Department of Chemistry, College of Sciences, University of Malaya, 50603 Kuala Lumpur, Malaysia, 2Department of Sciences and Mathematics, Universiti
Tenaga Nasional, KM 7 Jalan Kajang-Puchong, 43009 Kajang, Selangor, Malaysia.
(Received: February 9, 2012 - Accepted: May 2, 2012)
ABSTRACT
A new Cd(II) complex with a tridentate Schiff base derivative which was obtained from condensation of gallic hydrazid with 2-acetylpyridine has been
prepared. The structure of the ligand 3,4,5-Trihydroxybenzoic acid[1-(pyridyl)-ethylidene]hydrazone (GAPy) was confirmed using the X-ray structure analysis.
The elemental analysis, FTIR, UV-Vis, 1H NMR spectral and Thermal analysis indicates that the Schiff base ligand GAPy is a tridentate ligand which is coordinated
with the Cd(II) complex through N,N and O atoms. Thus, the acetate ion is a bidentate ligand that is coordinated with the metal ion through two O atoms.
Keywords: Schiff base derivatives, Cd(II) complexes, hydrazone derivatives complexes, spectroscopic characterization.
2-acetylpyridine (1.21 mL, 0.01 mmol). The mixture was refluxed in a water
bath for 6-8 h. The white precipitate formed was filtered, washed 3 times with
ethanol and crystallized with DMF. Elemental analysis found (calc.) %: C,
57.99 (58.53); H, 4.56 (4.56); N, 14.06 (14.63). The m.p was 155 C and the
yield was 65%.
1.
INTRODUCTION
Schiff bases from gallic hydrazides are well known as polydentate
ligands which are considered as an important class of ligands in coordination
chemistry.1 Thus, gallic hydrazide and its substituted derivative have been
ο
2-9
prepared and characterized during the past few years. Metal complexes of
1.3 Synthesis of the Cd(II) complex
tridentate Schiff base ligands with donor atoms such as (NNO) have attracted
considerable attention because they display anti-fungal activity against various
fungal such as Aspergillus Flavus, Trichophyton longifusus, Candida albicans
An ethanol solution (35 mL) of Cd(II) acetate (0.088 g, 0.33 mmol)
was added to an ethanol solution of 3, 4, 5-trihydroxybenzoic acid [1-
(pyridyl)- ethylidene]hydrazone (0.20g, 0.66 mmol) together with 4 drops of
triethylamine. The mixture was refluxed at room temperature for 10 h. The
product precipitated as a brown solid and was recrystallized from DMSO.
Elemental analysis found (calc.) %: C, 38.99(39.53); H, 2.75(2.95); N, 7.59
(7.68). The m.p was 255°C and the yield was 60%.
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and Microsporum canis.4, Moreover, these complexes display remarkable
antitumor activity against HL60 and A-549 cancer cell lines, and also display
antioxidative, anti-inflammatory, antimutagenic, anticarcinogenic and anti-
allergic activities.11 The hydrazone group has two imino and amino nitrogen
atoms whose valance electrons differ in their degree of hybridization. The
possibility of chelate formation via a hydrogen bond between the nitrogen atom
of a gallic hydrazones and the hydrogen atom of the OH group of salicyldehyde
has been reported.12-15 Since little work has been reported on Cd(II) complex
containing 3,4,5-Trihydroxybenzoic acid[1-(pyridyl)-ethylidene]hydrazide.
We prepared the schiff base from gallic hydrazide and synthesized the complex
with Cd(II) ion. Uv-Vis, IR, and TGA spectroscopy as well as X-ray diffraction
were used to examine the coordination site of the ligand and the geometry of
the complex.
3.
RESULTS AND DISCUSSION
TheSchiffbase(GAPy)wasobtainedwithagoodyieldbycondensinggallic
hydrazide with 2-acetylpyridine. Thus, the reaction of the Schiff base with the
metal salt gave a complex with the general formula [Cd(GAPy)(AcO)2].2H O
where GAPy=3,4,5-trihydroxybenzoic acid[1-(pyridyl)-ethylidene]hydrazi2de
and AcO = acetate ion. The prepared complex was solid, and was insoluble in
most organic solvents such as acetone, benzene, and dichloromethane except
for DMSO. The results of elemental analysis were in good agreement with the
calculated values from the proposed empirical formula.
2.
EXPERIMENTAL
3.1 Uv-Vis spectral studies
2.1 Techniques and Materials
The Uv-Vis spectrum of the ligand GAPy in DMSO showed absorption
bands at 270, 276 and 280, 289, 329 nm which were attributed to π → π*
and n→π* transitions respectively. The diamagnetic Cd(II) complex exhibited
absorption bands at 285 and 293 nm which were due to π g π* transitions.
Thus, the spectrum showed charge transfer LMCT at 302 nm. This is because
the electronic configuration of the Cd(II) complex is d10 which indicates the
absence of d-d electronic transition. Moreover, the absorption bands showed a
red shift with a hyper chromic effect which supported the coordination of the
ligand with the metal atom.19, 20
All chemicals were obtained from commercial sources and were used
without further purifications (Cd(II)acetate, gallic hydrazide, 2-acetylpyridine,
ethanol, DMSO, DMF, Triethylamine, KBr) from Merck (Darmstadt,
Germany).
Infrared spectra were obtained using KBr discs (4000-400 cm-1) on a
Perkin–Elmer FT-IR spectrometer (Kyoto, Japan). Measurement of UV-Vis
spectra were carried out using a Shimadzu UV-VIS spectrophotometer UV-
160 (Hitachi, Tokyo, Japan) in 10-3 M DMSO solution. Thermal analysis of the
complex was performed on a Perkin-Elmer Pyris Diamond DTA/TG Thermal
System under a nitrogen atmosphere at a heating rate of 10oC/min and within
a heating range of 30-900oC. Elemental analysis (C, H, N) was performed
by using a Flash EA 1112 Series elemental analyzer (St. Joseph, MI, USA).
Crystal data were obtained from APEX2 16; cell refinement: SAINT 16; data
reduction: SAINT. The program (s) used to solve the structure was SHELXS97
17; the program used to refine the structure was SHELXL97 17; molecular
graphics were analyzed using XSEED 18; and the software used to prepare the
data for publication was publCIF.
3.2 IR spectral studies
The infrared spectra of the free ligand GAPy showed strong bands at
3399 and 3351 cm-1, corresponding to
ν(ph-OH) and ν(NH) respectively.
These bands appeared in the spectra of the complex at 3439 and 3393 cm-1
which indicated that the OH and NH groups were not coordinated with the
Cd(II) ion. However, the spectrum of the ligand showed strong bands at 1618
and 1650 cm-1, corresponding to the ν(C=N) of azomethine and pyridine
respectively. These bands were shifted to lower frequencies by 16 and 18 cm-1
in the spectrum of the complex. Furthermore, the ν(N-N) band was observed
at 1032 cm-1, but was shifted to higher frequency at 1042 cm-1 after complex
formation. The coordination through the N atom was further supported by the
occurrences of new bands at 400-450 cm-1 in the spectra of the complex, which
2. 2 Synthesis of the ligand 3,4,5-trihydroxybenzoic acid[1-(pyridyl)-
ethylidene]hydrazone
The Schiff base was prepared by adding 25 mL of an ethanolic solution
of gallic hydrazide (1.84 g, 0.01 mmol) to 25 mL of an ethanol solution of
e-mail: drshaimaa611@yahoo.com
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Alhadi, Abeer A.
