Synthesis and Characterization of Ni (II) Complex with Tridentate Ligand of Schiff s Bases of Salicylaldehyde with Thiocyanate Ligand

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1 J. Appl. Environ. Biol. Sci., 3(8)75-80, , TextRoad Publication ISS: Journal of Applied Environmental and Biological Sciences Synthesis and Characterization of i (II) Complex with Tridentate Ligand of Schiff s Bases of Salicylaldehyde with Thiocyanate Ligand Roghayeh Fekri 1, Behrooz Shaabani 2 1 Department of Chemistry, Ardabil branch, Islamic Azad University, Ardabil, Iran. 2 Department of Inorganic Chemistry, Faculty of Chemistry, Tabriz University, Tabriz, Iran. ABSTRACT A group of combinations which have more importance in biological studies, biochemistry and also catalytic applications are Schiff base complexes. They have been considered by the chemists. I this work, we reported the synthesis and characterization of tridentate Schiff base ligand from the reaction of isonicotinohydrazide with salicylaldehyde. Metal complex of the Schiff base was prepared from salt of i(ii) on 1:1(ligand: metal).thiocyanate ligand was used in addition to coordinate to transition metal ion, which presents a novel in transition metal complex.the obtained ligand and complex were investigated using techniques such as IR, 1 HMR, 13 CMR,UV/Vis,CV, measurement of electrical conduction, and melt point. The comparison of spectroscopic results for the ligand and complex an also visible absorption spectra for complex suggest that ligand act as tridentate.in UV/Vis spectrum,the observed transfers in ligand include the transfer between n-π * and π- π * orbitals, and in the transfer is related to d-d in complex. KEY WRDS: Schiff base, i (II) complex, Salicylaldehyde, Thiocyanate ITRDUCTI Considerable interest has been shown in metal complexes of thiocarbazate derivatives especially those having S donor sequences. These compounds warrant further study because they provide an interesting series of ligands whose properties can be greatly modified by introducing different organic substituents, thereby giving variation in donor properties. These ligands interact with metal ions to give structures of different geometry and properties and they are often biologically active [1]. Ligand, a metal surrounded by a cluster of ions or molecule, is used for preparation of complex compounds named as Schiff s bases, which are condensation products of primary amines and aldehydes or ketones (RCH=R, where R & R represents alkyl and/ or aryl substituents)[2]. Molecular recognition due to noncovalent intermolecular interactions between two different molecules has become an important subject in areas of chemistry, biology and physiology. In particular, the selective binding via interactions such as hydrogen bonding and π- π aromatic stacking between the receptor and the neutral guest molecule has been known as the basis of the main concept in molecular recognition. [3].The preparation of macrocyclic polyamine ligands bearing functional pendant donor groups and their subsequent ligation to various metal ions has been an active area of research in recent years. Macrocyclic ligands containing a heteroatom are important complexing agents for cations, anions and molecules [4]. The complexes of azo compounds also exhibits bacteriostatic and other biochemical activities, heterocyclie azo Schiff base and their complexes with transition metal ions are also of importance due to their complexing, catalytieal biological properties[5]. Studies of a new kind of chemotherapeutic Schiff bases are now attracting the attention of biochemists. Earlier work reported that some drugs showed increased activity, when administered as metal complexes rather than as organic compounds [6]. Molybdenum has been found to be an important element in biological systems.it possesses a large number of stable and variable oxidation states as well as coordination numbers which can vary from four to eight. Although only a minor constituent of the earth s crust, molybdenum is readily available to biological systems because of the solubility of molybdate salts in water [7]. Studies of new kinds of chemotherapeutic Schiff bases are now attracted the attention of biochemists. Schiff bases of o-phenylenediamine and its complexes have a variety of applications including biological, clinical and analytical [8]. The signals of the H MR spectra as well as the important bands in the IR spectra are considered and discussed in relation to molecular structure [9]. Arylazo derivatives of 1, 3-diketones have gained considerable importance in recent years because of their application in the laboratory as acidbase, redox, metallochromic and other indicators[10]. The transition metal complexes having oxygen and nitrogen donor Schiff bases possess unusual configuration, structural lability and are sensitive to the molecular environment [11]. Tetradentate Schiff base ligands were synthesized by the reaction of diamines with the corresponding salicylaldehyde derivative [12]. A large number of Schiff bases and their complexes have been studied for their interesting and important properties, their ability to reversibly bind oxygen, catalytic activity in hydrogenation of olefins and transfer of an amino group3, photochromic properties, and complexing ability towards some toxic metals [13]. In principle, the central transition metal atoms of different soft and hard Lewis acidity usually need to be satisfied in the most suitable fashion [14]. The coordination chemistry of hydrazones is an intensive area of study and numerous transition metal complexes of these ligands have been investigated [15]. Lanthanide complexes typically exhibit high coordination numbers and structural *Corresponding Author: Roghayeh Fekri, Department of Chemistry, Ardabil branch, Islamic Azad University, Ardabil, Iran. 75

2 Fekri and Shaabani, 2013 diversity. Unlike their transition metal counterparts, the solid-state coordination geometries of lanthanides are difficult to predict, particularly for complexes of simple mono- and bi-dentate ligands [16]. MATERIALS AD METHDS Synthesis of Ligand In a 250 ml ballon we solved isonicotinohydrazide (10 mmol and 1.37 g) in 30 ml ethanol and refluxed it for half an hour. Then we added salicylaldehyde (10 mmol) and refluxed it for 3 to 4 hours on a magnetic mixer and we continued refluxion until sediment formed. Also sample electrical conduction in ethanol solvent was measured. The synthesis of H 2 L ligand has been illustrated in figure1. H H 2 + H H EtH/Reflux H H isonicotinohydrazide Figure (1). Synthesis of the tridentate Schiff base ligand ( H 2 L) Synthesis of Complex After preparation of ligand, complex was formed in following way: With respect to this point that ligand and metal must be in the proportion 1:1to make complex. Synthesized ligand and 25 ml pure ethanol were poured into beaker and the compound was heated for 1 hour during the mixing. Metal salt was added to the solution and mixing as well as heating was continued for 1 hour. Afterwards, thiocyanate ligand was added and it was refluxed for 3-4 hour. The structure of metal complex has been illustrated in figure 2. K 2 M S C C S M Figure (2). Structure of the complex RESULTS AD DISCUSSI In IR spectrum the C= band for synthesized ligand in cm -1 frequency confirms the ligand formation so that the frequency was in cm -1 rang in the case of i metal complex.in UV/Vis spectrum the absorption band in 370 nm and 335 nm in synthesized ligand related to n-π * and π- π * indicates the presence of C= band. In obtained i (II) metal complex, the observed wavelength in nm rang is related to d-d transfer.cyclic voltammogram synthesized complex i (II) with 0.1 Vs-1 scan rates in 1.5 to volt was studied in DMS solvent. In comparing ligand graph with obtained complex in above graph a peak in Ea = V zone it is observed that it has moved, compared to ligand peak. Also a relatively high peak is seen in Ea = 0.75 V zone.in lower zone of the graph i.e in reduction zone two tiny peak Ec = 0.90 V and Ec = -.75 V are observed that hasmoved in reduction zone compared to ligand peak. In a comparison on oxidation and reduction peaks of thisgraph, it can be concluded that the appeared peak has been seen in oxidation and also reduction zones. So its electrochemical behavior shows reversible state of the complex. Since ligand and metal appear in a place close to each other, the peak of oxidation zone is relatively wide and high. Due to the movements which have been done in oxidation and reduction zones, the considered combination formation has been confirmed and the prepared complex is electroactive Figures (3-9). 76

3 J. Appl. Environ. Biol. Sci., 3(8)75-80, Transmittance [%] Wavenumber cm Figure (3). IR Spectroscopy of the tridentate Schiff base ligand (H 2 L) C:\Program Files\PUS\meas\Sample description.141 Sample description Instrument type and / or accessory 29/05/2012 Page 1/1 Figure (4). IR Spectroscopy of the complex i (II) Figure(5). UV- Vis Spectroscopy of the tridentate Schiff base ligand (H 2 L) 77

4 Fekri and Shaabani, 2013 Figure(6).UV- Vis Spectroscopy of the complex i (II) Figure(7). CV Spectroscopy of the complex i(ii) Figure(8). 1 HMR Spectroscopy of the tridentate Schiff base ligand (H 2 L) 78

5 J. Appl. Environ. Biol. Sci., 3(8)75-80, 2013 Figure(8). 1 HMR Spectroscopy of the tridentate Schiff base ligand (H 2 L) Figure(8). 1 HMR Spectroscopy of the tridentate Schiff base ligand (H 2 L) Figure(9). 13 CMR Spectroscopy of the tridentate Schiff base ligand (H 2 L) 79

6 Fekri and Shaabani, 2013 Figure(9). 13 CMR Spectroscopy of the tridentate Schiff base ligand (H 2 L) The chemicals used in this research Compounds Product Molecular mass Purity percent Density Isonicotinohydrazide Merck % - Bromide ickel Merck % - Salicylaldehyde Merck % 1.17 Ethanol Merck % 0.79 DMF Merck % - DMS Merck % - Thiocyanate Potassium Merck % - The electrical conduction and melt point Compound Melt point Electrical conduction Ligand c 1.63 µs.cm -1 Complex i (II) c 99.1 µs.cm -1 REFERECES [1] M.T.H. Tarafder, Teng-Jin Khoo, Karen A. Crouse,A.M. Ali, B.M. Yamin, H.-K. Fun, Polyhedron 21 (2002) 2691_2698. [2]Sh.Kumar,D. athdhar, P.. Saxena, J. Scien. Res. 2009(68), [3] M. Park, Y. Kim, Thin Solid Films 363 (2000) [4]S. Ilhan,, H. Temel,Journal of Molecular Structure 891 (2008) [5] L.V. Gavali, P.P. Hankarep, Journal of Physical Sciences, Vol. 11, 2007, [6].Raman, J. Dhaveethu, A. Sakthivel, J. Chem. Sci., Vol. 119, o. 4, July 2007, pp [7] R. Chakravarthy, D. Kumar, J. Chem. Sci. Vol. 123, o.2, March 2011, pp [8] A. agajothi, A. Kiruthika, S. Chitra, K. Parameswari, Journal of Chemical Sciences, Vol. 3(2), 2013, [9]M. Issa, M. Khedr, H. Pizh, Journal of Chinese Chemical, 2008, 55, [10] M. Ummathur, P. Sayuderi, K. Krishnankotty, Journal of the Argentine Chemical, Vol. 97, 2009, [11] B. Cristovao, J. Serb. 76 (12), 2011, [12] M. Asadi, H. Sepehrpour, K. Mohammadi, J. Serb. Chem. 76(1), 2011, [13] G. Mohamed, M. mar, A. Hindy,, J. Chem. 30 (2006), [14]. Karabocek, S. Karabocek, F. Kormali,, J. Chem, 31(2007), [15] S. Yaul, A. Yaul, G. Pethe, A. Aswar, Journal of Scientific, 4(4), 2009, [16] S. Salehzadeh, M. Bayat, L. Davoodi, R. Golbedaghi, V. Izadkhah, J. Serb. Chem, 24(1), 2010,