Research Article
Open Access
Synthesis and Spectroscopic Investigation of Novel
Nickel(II) Complexes from Pentadentate Schiff Base
Ligand
Rangaswamy Venkatesh and Kannappan Geetha*
PG& Research Department of chemistry, Muthurangam Govt. Arts College(Autonomous), Vellore-2
*Corresponding author: Dr. K Geetha, PG& Research Department of chemistry, Muthurangam Govt. Arts College (Autonomous), Vellore-2,
Tel: +91 09486925596; +91 0416 2262068; Fax: +91 0416 2263768; E-mail: senthil_geetha@rediffmail.com
Received: May 25, 2015; Accepted: June 14, 2015; Published: July 01, 2015
Citation: Venkatesh, Geetha K (2015) Synthesis and Spectroscopic Investigation of Novel Nickel(II) Complexes from Pentadentate
Schiff Base Ligand. SOJ Mater Sci Eng 3(2): 1-5. DOI: http://dx.doi.org/10.15226/sojmse.2015.00121
AbstractTop
The coordination chemistry of dinucleating ligands is currently
an area of great activity. One reason for this is the facile synthesis
of dinuclear species toward model compounds of metallo-enzymes.
On the other hand, these multidentate ligands might be useful as
building blocks for high-nuclearity compounds. Three different para
substituted dinuclear nickel(II) complexes [Ni2L(O2CC6H4-p-X)] [
X= NO2(1), Cl(2),OCH3(3) ] were synthesized by the reaction of
corresponding precursor with pentadentate Schiff base ligand. The
ligand was characterized by UV-Visible, FTIR, NMR studies. The
synthesized complexes were characterized by molar conductance,
UV- Visible, FTIR, LCMS spectral studies.
Keywords: Penta-Dentate Schiff Base Ligand; Nickel(II) Precursors; Novel Nickel(II) Complexes
Keywords: Penta-Dentate Schiff Base Ligand; Nickel(II) Precursors; Novel Nickel(II) Complexes
Introduction
Over the past two decades, extensive research has been carried
out on symmetrical bis-Schiff base ligands and their transition
metal complexes, which can be prepared by usual condensation of
one mole of diamine and two moles of β-diketone or an aromatic
O-hydroxy carbonyl compound [1-5]. But there are only a few
reports regarding with synthesis of unsymmetrical Schiff bases
derived from equimolar condensation of a diamine and different
aldehydes / ketones which is more difficult to obtain. During the
recent years, there has been a remarkable interest in the design,
synthesis and characterization of transition metal complexes of
unsymmetrical Schiff base ligands from the fact that the central
metal ions in natural systems are in unsymmetrical organic
moieties [6-12]. Hence transition metal complexes synthesized
from unsymmetrical Schiff bases serve as models of relevance
to bio-inorganic chemistry such as metallo proteins and metallo
enzymes in which transition metal ions are found usually in a
disorted environment. Unsymmetrical Schiff base complexes
have shown wide spectrum of applications such as biochemical,
analytical, and antimicrobial agents [13, 14].
Sau-Fun et al reported unsymmetrical bis-Schiff base ligands by partial displacement of the symmetrical bis-Schiff bases of ethylenediamine and salicylaldehyde/ O-hydroxyacetophenone/ acetylacetone/ benzoylacetone which have led to the formation and isolation of unsymmetrical Schiff base ligands. Nickel(II) and copper(II) complexes of these ligands have been prepared and characterized [15,16].
This paper reports on the synthesis and characterization of Nickel (II) complexes using pentadentate Schiff base ligand obtained from 5-nitro salicylaldehyde with salicylaldehyde and 1,3-diamino-2-propanol.
Sau-Fun et al reported unsymmetrical bis-Schiff base ligands by partial displacement of the symmetrical bis-Schiff bases of ethylenediamine and salicylaldehyde/ O-hydroxyacetophenone/ acetylacetone/ benzoylacetone which have led to the formation and isolation of unsymmetrical Schiff base ligands. Nickel(II) and copper(II) complexes of these ligands have been prepared and characterized [15,16].
This paper reports on the synthesis and characterization of Nickel (II) complexes using pentadentate Schiff base ligand obtained from 5-nitro salicylaldehyde with salicylaldehyde and 1,3-diamino-2-propanol.
Experimental Materials and methods
1,3-diamino-2-propanol was purchased from Alfa Aesar, all
other chemicals and solvents were purchased from commercial
sources and were used after purification. Conductance of
complexes was recorded using Elico conductometer. UV-Vis
spectra were recorded using Systronics spectrophotometer
operating in the range of 200-800 nm with quartz cell. FT-IR
spectra of ligand and complexes were obtained on a Schimadzu
IR-Affinity-I spectrometer and samples were prepared using
KBr. 1H NMR spectrum of Schiff base ligand was recorded using
Bruker 400 MHz model.
Synthesis of ligand
The ligand was synthesized by using 1, 3-diamino-2-
propanol( 10 mmol) with 5-nitro salicylaldehyde (10 mmol) and
salicylaldehyde (10 mmol) in the ratio of 1:1:1 using ethanol as a
solvent and the mixture was refluxed for 6 hours. Colour change
was observed and the reaction was monitored by TLC primarily
using hexane as eluent. It was characterized by UV-Vis, FT-IR and
1HNMR spectral studies.
Synthesis of Nickel (II) Precursors
The Nickel(II) precursors were synthesized by using organic
acids para-nitro benzoic acid, para-chloro benzoic acid and paramethoxy
benzoic acid( 10 mmol) with NaOH( 20 mmol) were
stirred for 10 minutes and NiSO4.6H2O( 20 mmol) was added to
above mixture and magnetically stirred with 30 minutes. The
ratio of organic acid, base and metal was taken as 1:2:2 for the synthesis of Nickel (II) Precursors. The crude green Nickel (II)
precursors obtained was washed thoroughly with water and
dried well. The Nickel (II) precursors obtained was used for the
synthesis of Nickel (II) complexes.
Synthesis of Nickel (II) complexes
A general method was used for the preparation of Dinuclear
Nickel(II) complexes. The ligand (2 mmol) with KOH (6 mmol)
and Nickel(II) precursor( 2 mmol) was refluxed for 6 hours
using ethanol as a solvent. The ratio of the ligand, KOH, Nickel
(II) precursors were taken as 1:3:1 for the synthesis of Dinuclear
Nickel(II) complexes. The complexes formed were characterized
by UV-Vis, FT-IR, Conductivity measurement and LCMS. The
scheme for the preparation of the ligand and complexes are given
below. The scheme of the ligand and its complex are shown in
Figure 1 and Figure 2.
Results and Discussion
Conductance Measurements
Molar Conductivity measurements values revealed nonelectrolytic
nature of Nickel (II) complexes [17], since for the
molar conductance values are in the range for non-electrolytes.
The solvent used for conductance measurement is DMF. The
physical properties and conductance of the metal complexes
values are listed in Table.1.
UV-Visible Spectra
The UV-Visible spectra of the ligand was recorded in DMF
in the wavelength range 200-800 nm. The complexes were
recorded in the DMF solution in the above wave length range. The
band observed at 245nm was due π-π* transition of the benzene
ring present in the ligand and it shifted to higher wavelength(red
shift) upon complexation and the band was observed at 255, 250
and 270 nm respectively for complex-I,II &III. The band at 355
Figure 1: The scheme of the Ligand.
Figure 2: The scheme of the complex.
Table 1: Physical properties and Conductance of the metal complexes.
Compound |
Molecular formula |
Colour |
Molar Conductance (S cm2 mol-1) |
Complex-I |
C24H18N4O9Ni2 |
Light Green |
4.0 |
Complex-II |
C24H18N3O7ClNi2 |
Light Green |
12.9 |
Complex-III |
C25H21N3O8Ni2 |
Light Green |
4.9 |
Table 2: IR data for ligand and its complexes.
Functional group |
Ligand (cm-1) |
Complex-I (cm-1) |
Complex-II (cm-1) |
Complex-III(cm-1) |
ʋ(C=N) |
1635 |
1618 |
1620 |
1616 |
ʋ(C-O)(Phenolic) |
1307 |
1313 |
1308 |
1315 |
ʋ(-OH) |
3142 |
- |
- |
- |
ʋ(Ni-N) |
- |
524 |
545 |
530 |
ʋ(Ni-O) |
- |
466 |
474 |
466 |
ʋ(Ni-OCO) |
- |
1579,1475 |
1579, 1471 |
1583,1487 |
nm was due to π-π* transition of the azomethine group present
in the ligand and it shifted to higher wave length observed at
390, 370 and 380nm. This shows the coordination of metal with
the azomethine nitrogen [18]. The weak band observed at 470,
480 and 460 nm was due to n-π* transition of complex-I, II &III.
The new characteristic band at 640, 642, 641 nm was due to d-d
transition of complex-I, II& III. UV-Visible spectrum for ligand
and its complexes shown in Figure 3.
Figure 3: UV-Visible spectrum for ligand and its complexes shown.
Figure 4: The NMR spectrum of ligand.
Figure 5: The mass spectrum of complex (III).
Infrared Spectra
In order to study the binding mode of ligand to metal in
the complexes, IR spectrum of the free Schiff base ligand was
compared with the spectra of the metal complexes. The free
ligand exhibits IR peaks at 3142 cm-1 (O-H), 1635 cm-1 (C=N) and
1307 cm-1 phenolic (C-O) [19,20]. In complexes the peak due to
(O-H) of the ligand disappeared indicating the co-ordination of
phenolic oxygen to the metal ion via deprotonation. This was
further supported by upward shift to the phenolic (C-O) mode.
The peak at 1635 cm-1 was due to azomethine group of the ligand
and it shifted to lower frequency after complexation. This shows
the co-ordination of metal with azomethine nitrogen [21]. Some
new bands have also appeared indicating the complexation of
metal with the ligand corresponds to (Ni-N), (Ni-O) and (Ni-
OCO). IR data for ligand and its complexes are shown in Table.2
1H-NMR of the Ligand
The ligand was characterized by 1H-NMR and the values
were obtained at 2.5 δ for secondary alcohol proton; 3.4 δ
for methylene proton; 6.69 δ for azomethine group; 8.78 δ for
phenolic proton. The solvent used for NMR spectrum is DMSO-d6.
NMR data for ligand shown in Figure 4
Mass spectrum of the Complex
The mass spectrum of complex (III) exhibited peak at m/z
606.97, this is in good agreement with the proposed molecular
formula of molecular weight 607. The peak at 166 is due to
C7H4NO4, the peak at 387 is due to C11H12N2
O6Ni2 and the peak at
487 is due to C17H14N3O7Ni2. The mass spectrum of complex (III)
shown in Figure 5.
Conclusion
In the present work three dinuclear nickel (II) complexes
were synthesized and characterized by various analytical
techniques like molar conductance, electronic, vibrational, NMR
and LCMS studies. IR spectral data showed that the ligand acts
as pentadentate coordinating through azomethine nitrogen and
oxygen atoms. The lower molar conductance values suggested
the non-electrolytic nature of the complexes.
ReferencesTop
- Ueno K & Martell AE. J Phys Chem. 1995;59:998.
- Mc Carthy PJ, Hovey RJ, Ueno K and Martell AE. Inner Complex Chelates. I. Analogs of Bisacetylacetoneethylenediimine and its Metal Chelates1,2 . J Am Chem Soc. 1955;77(22):5820.
- Bailes RH, Calvin M. The oxygen-carrying synthetic chelate compound. VII. Preparation1. J Am Chem Soc. 1947;69(8):1886-1893. DOI: 10.1021/ja01200a013
- Carter MJ, Rillema DP, and Basolo F. Catalytic Activation of Dioxygen by Metal Complexes. J Am Chem Soc. 1974;96:392.
- Tan SF, Ang KP, Jatchandran HL. Synthesis and Characterisation of copper (II), Ni(II) and palladium(II) complexes of some Schiff bases of dehydro acetic acid. Trans Met Chem. 1984;9(10):390-395.
- Pandey YS and Mathur P. Polyhedron. 1994:13:3111.
- Kwiatkowski M, Bandoli G. J Chem Soc. Dalton Trans. 1992;379.
- Costes JP, Fernandez Garcia ML. Easy synthesis of half-units: their use as ligands or as precursors of non-symmetrical base complexes. Inorganica Chimica Acta. 1995;237(1):57-63. doi:10.1016/0020-1693(95)04641-L.
- Jebbar-sid SD, Banali-Baitich O, Deloume JD. Polyhedran. 1997;16:2175.
- Atkins R, Brewer G, Kokot E, Mockler GM, Sinn E. Copper(II) and nickel(II) complexes of unsymmetrical tetradentate Schiff base ligands, Inorg. Chem. 1985;24(2):127-134. DOI: 10.1021/ic00196a003
- Kwiatkowski E, Kwiatowski M, Inorg. Chim. Acta. 1986;117:145.
- Kwiatkowski M and Kwiatkowski E. J Chem Soc. Dalton Trans. 1985; 803-806. DOI: 10.1039/DT9850000803
- Nora H, Al-Sha'alan H. Antimicrobial activity and spectral, Magnetic and thermal studies of some transition metal complexes of a Schiff base hydrazone containing a quinoline moiety. Molecules. 2007;12(5):1080-1091.
- Nishant N, Parveen S, Dhyani S and Asma. Antimicrobial polyesters containing Schiff-base metal complexes. J Coord Chem. 2009;62(7):1091-1099.
- Tan SF and Ang KP. Trans Met Chem. 1998;13:64-68.
- Ray MS, Bhattacharya R, Chaudhuri S, Right L, Bocelli G, Mukhopadhyay G, Ghosh A. Synthesis, characterisation and X-ray crystal structure of copper(II) complexes with unsymmetrical tetradentate Schiff base ligands: first evidence of Cu(II) catalysed rearrangement of unsymmetrical to symmetrical complex. Polyhedron. 2003;22(4):617-624. doi:10.1016/S0277-5387(02)01435-3
- Geary WJ. The use of conductivity measurements in organic solvents for the characterization of coordination compounds. Coord chem Rev. 1971;7(1):81-122.
- Nevin Turan and Memet Sekerci. Synthesis and characterization of Co(II), Ni(II), Cd(II) and Cu(II) complexes of Bis-schiff bases obtained from 1,8- Diamino naphthalene. J Chem Soc Pak. 2009;31(4):564-568.
- Manikshete AH, Awatade MM, Sarsamkar SK, Asabe MR. Synthesis, characterization, antimicrobial, anticancer and antidiabetic activity of new Manganeae (II), Nickel (II) and Cobalt (II) complexes with Salicylaldehyde-4-chlorobenzoylhydrazone. International Journal of Engineering Science Invention. 2015;4(1):22-29.
- Mohanan K, Subhadrambika N, Selwin Joseyphus R, Swathy SS, Nisha VP. Synthesis, spectroscopic characterization, solid state d.c electrical conductivity and biological studies of some lanthanide(III) chloride complexes with a heterocyclic Schiff base ligand. Jounal of Saudi chemical Society. 2012. doi:10.1016/j.jscs.2012.07.007
- Marius Andruh, Olivier Kahn, Joelle Sainton, Yves Dromzee, Suzanne Jeannin. Oxophily of gadolinium(III) and synthesis of dissymmetric di(Schiff bases) and Dissymmetric dinuclear compounds-crystal-structure of [Cu2L'(OH)] (CLO4)2.H2O with L'=-6-[N-Dimethyl Amino)Propyl)Formimidoyl] Phenolato" Inorg. Chem. 1993;32(9):1623-1628. DOI: 10.1021/ic00061a018