Conductometric and Spectrophotometric Studies of the Thermodynamics Complexation of Cu2+, Hg2+, Ni2+, Zn2+, Cd2+ and Co2+ Ions with (E)-(Pyridine -2-Ylmethylidene)({2-(E)-(Pyridine-2- Ylmethylidene)Amino]ethyl} Ligands in Acetonitrile Solution and Comparison of Their Behaviors

Document Type: Original research article


1 Department of Chemistry, Payame Noor University (PNU), P.O. BOX, 19395-3697, Tehran, Iran

2 Faculty of Chemistry, Tarbiat Modarres University, Tehran, Iran


A new pyridine derivative ligand, (E)-(Pyridine-2-ylmethylidene)({2-(E)-(Pyridine-2-ylmethylidene)amino]ethyl}has been synthesized and kf value of its complexes with Cu2+, Ni2+, Cd2+, Zn2+, Hg2+ and Co2+has been determined by spectrophotometric and conductometric methods in acetonitrile at various temperatures. The formation constants (Kß = K1 × K2) of the 1:1 and 1:2 (metal ion to ligand) complexes were calculated by computer fitting of the absorbance-mole ratio data, and molar conductance-mole ratio data at different temperatures, and   found that complexes to vary in acetonitrile solvent in the order of Cu2+ >Hg2+>Zn2+>Co2+> Cd2+> Ni2+>Ag+. The enthalpy and entropy changes of the complexation reaction were evaluated from the temperature dependence of formation constants.



[1]     R. Ziessel, Schiff-based bipyridine ligands. Unusual coordination features and mesomorphic behavior, Coord. Chem. Rev. 216-217 (2001) 195-223.

[2]     P.A. Vigato and S. Tamburini, The challenge of cyclic and acyclic Schiff bases and related derivatives, Coord. Chem. Rev. 248 (2004) 1717-2128.

[3]     C. Janiak, Engineering coordination polymers towards applications, Chem. Soc. Dalton Trans. 14 (2003) 2781-2804.

[4]     S.D. Ittel, L.K. Johnson and M. Brookhart, Late-Metal Catalysts for Ethylene Homo- and Copolymerization, Chem. Rev. 100 (2000) 1169-1204.

[5]     B.L. Small and M. Brookhart, Polymerization of Propylene by a New Generation of Iron Catalysts:  Mechanisms of Chain Initiation, Propagation, and Termination, Macromoleculares 32 (1999) 2120-2130.

[6]     C.M. Liu, R.G. Xiong, X.Z. You and Y.J. Liu, Crystal structure and some properties of a novel potent Cu2Zn2SOD model Schiff base copper (II) complex {[Cu (bppn)] (ClO4)2}2·H2O, Polyhedron 15 (1996) 4565-4571.

[7]     J. Szklarzewicz, A. Samotus, J. Burgess, J. Fawcett and D.R. Russel, Structural and spectroscopic characterization of a dicyanooxomolybdenum(IV) complex with a tetradentate schiff-base ligand, J. Chem. Soc. Dalton Trans. 18 (1995) 3057-3061.

[8]     S. Gourbatsis, S.P. Perlepes, I.S. Butler and N. Hadjiliadis, Zinc(II) complexes derived from the di-Schiff-base ligand N,N′-bis[1-(pyridin-2-yl)ethylidene]ethane-1,2-diamine (LA) and its hydrolytic-cleavage product N-[1-pyridin-2-yl)ethylidene]ethane-1,2-diam-ine(L): preparation, characterization and crystal structure of the 5-coordinate species [ZnLCl2], Polyhedron 18 (1999) 2369-2375.

[9]     P.K. Bowyer, K.A. Porter, A.D. Rae, A.C. Willis and S.B. Wild, From helicate to infinite coordination polymer: crystal and molecular structures of silver (I) complexes of readily prepared di-Schiff bases, J. Chem. Soc. Chem. Commun. 10 (1998) 1153-1154.

[10]  S. Gourbatsis, N. Hadjiliadis, S.P. Perlepes, A. Garoufis and I.S. Butler, Structural and spectroscopic characterization of a cationic aquanitrato copper (II) complex with tetradentate Schiff- base ligand N, N'- bis[1-(2 - pyridyl) ethylidene] ethane – 1 , 2 -diamine, Transition Met. Chem. 23 (1998) 599-604.

[11]  R.G. Pearson, The HSAB Principle - more quantitative aspects, Inorg.  Chim.  Acta 240 (1995) 93-98.

[12]  P.J. Stang and B. Olenyuk, Self-Assembly, Symmetry, and Molecular Architecture:  Coordination as the Motif in the Rational Design of Supramolecular Metallacyclic Polygons and Polyhedra, Acc. Chem. Res. 30 (1997) 502-518.

[13] D. Braga, Intermolecular Interactions in Nonorganic Crystal Engineering, Acc. Chem. Res. 33 (2000) 601-608.

[14]  B.F. Abrahams, B.F. Hoskins, D.M. Michall and R. Robson, Assembly of porphyrin building blocks into network structures with large channels, Nature 369 (1994) 727.

[15] P. Schwarz, E.  Siebel, R.D. Fischer, D.C. Apperley, N.A. Davies and R.K. Harris, Angew. [(CoCp2) ⊂ Fe (μ-CNSnMe3NC) 3]: A Purely Organometallic Channel Inclusion Compound, Chem., Int. Ed. Engl. 34 (1995) 1197-1199.

[16]  O.M. Yaghi, G. Li and H. Li, Selective binding and removal of guests in a micro porous metal–organic framework, Nature 378 (1995) 703.

[17]  G.B. Gardner, Y.H. Kiang, S. Lee, A. Asgaonkar and D. Venkartraman, Exchange Properties of the Three-Dimensional Coordination Compound 1,3,5-Tris(4- ethy-nylbenzonitrile)benzene ·AgO3SCF3,  J. Am. Chem. Soc. 118 (1996) 6946-6953.

[18]  G. Denti, S. Serroni, S. Campagna, A. Juris, M. Ciano and V. Balzani, Decanuclear homo- and heterometallic polypyridine complexes: syntheses, absorption spectra, luminescence, electrochemical oxidation, and inter-component energy transfer,  Perspect. Coord.   Chem. 114 (1992) 2944-2950.

[19]  H. Khajesharifi and M. Shamsipur, Spectrophotometric study of the thermo-dynamics of complexation of lithium and sodium ions with dibenzo-24-crown-8 in binary dimethylsulfoxide-acetonitrile mixt-ures using murexide as a Metallochromic Indicator, J. Coord. Chem 35 (1995) 289-297.

[20]  M. Payehghadr, A.A. Babaei, L. Saghatforoush and F. Ashrafi, Spectro-photometric and conductometric studies of the thermodynamics complexation of Zn2+, Cu2+, Co2+, Ni2+ and Cd2+ ions with a new schiff base ligand in acetonitrile solution, Afr. J. Pure Appl. Chem. 3 (2009) 092-097.

[21] M. Shamsipour, A. Avanes, G. Aghapour and H. Sharghi, Spectrophotometric studies of acidity constant and Cu2+ ion complexation of  1-Hydroxy-2-(prop-2’- enyl)-4-(prop-2’-enyl-oxy)-9,10-anthraquinone in methanol-water mixtures, Pol. J. Chem. 75 (2001) 1533-1541.