J. Iran. Chem. Soc., Vol. 8, No. 3 September 2011, pp.734~749.

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Two Zn(II) and Cd(II) Compounds Derived from 9-Aminoacridine: Syntheses, Characterizations, Crystal Structures and Solution Studies

J. Attar Gharamalekia, H. Aghabozorgb,*, Z. Derikvandc, M.M. Olmsteadd, A. Shokrollahie, R. Aghaeie and M. Shamsipurf

aYoung Researchers Club, Islamic Azad University, North Tehran Branch, Tehran, Iran
bFaculty of Chemistry, Islamic Azad University, North Tehran Branch, Tehran, Iran
cDepartment of Chemistry, Faculty of Science, Islamic Azad University, Khorramabad Branch, Khorramabad, Iran
dDepartment of Chemistry, One Shields Avenue, University of California, Davis, CA 95616, USA
eDepartment of Chemistry, Faculty of Science, Yasuj University, Yasuj, Iran
fDepartment of Chemistry, Razi University, Kermanshah, Iran

The aqueous reactions of zinc(II) and cadmium(II) nitrate and pyridine-2,6-dicarboxylic acid, (pydcH2), with 9-aminoacridine, (AAcr), resulted in the formation of two new proton transfer compounds, (AAcrH)2[Zn(pydc)2].3H2O (1) and (AAcrH)2[Cd(pydc)2].4H2O(2). The compounds were characterized using IR spectroscopy and single crystal X-ray diffraction. Both compounds crystallized in the triclinic crystal system, space group P, with two molecules per unit cell. The anions were six-coordinate complexes with distorted octahedral geometries around the Zn(II) and Cd(II) centers. The dihedral angles indicated that the two (pydc)2- ligands were almost perpendicular to each other. The complex anions of [M(pydc)2]2- were neutralized with (AAcrH)+ cations. These cations formed extended stacks throughout the structures. The water molecules clustered around cyclic tetramers, bridging the anions and forming a link to the aminoacridiunium stacks. A potentiometric pH titration method was used to investigate the protonation constants of AAcr and pydc, the pydc-AAcr proton transfer equilibrium constants, and the stoichiometries and stabilities of complex formation with Zn2+ and Cd2+ ions in 50% dioxane-50% water.

Keywords: Pyridine-2,6-dicarboxylic acid, 9-Aminoacridine, Zn(II) and Cd(II) complexes, Crystal structures, Solution studies

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