Keywords
EDTA
Coordination Polymer
How to Cite
Abstract
The coordination behavior of ethylenediaminetetraacetic acid (EDTA) toward transition-metal ions plays a decisive role in determining the structural stability and physicochemical properties of coordination polymers. In the present study, the synthesized poly[ethylenediaminetetraacetato-aqua-disodium-nickel(II)] coordination polymer was investigated by Fourier Transform Infrared (FT-IR) spectroscopy in order to establish the coordination mode of the ligand and verify the metal-ligand bonding environment. The FT-IR spectrum exhibits broad absorption bands at 3461 and 3374 cm-1, which are assigned to the stretching vibrations of coordinated water molecules involved in hydrogen-bonding interactions. Characteristic asymmetric stretching vibrations of coordinated carboxylate groups appear at 1591 and 1475 cm-1, whereas the corresponding symmetric vibrations are observed at 1393 and 1359 cm-1 The frequency separation between these bands confirms that the carboxylate oxygen atoms actively participate in coordination with the Ni(II) center. Additional absorptions at 1316 and 1295 cm-1 originate from C–N stretching vibrations, indicating that the nitrogen donor atoms of EDTA are also involved in metal coordination. The appearance of new bands within the 709–444 cm-1 region provides direct spectroscopic evidence for the formation of Ni-O and Ni-N coordination bonds
References
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