Keywords
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Keywords: Cu(II) coordination polymer, Magnetic studies, Crystal structure, Spectroscopic studies, Amino acid
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Abstract
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10 Abstract
11 A 2D coordination polymer of Cu(II) was synthesized by the reaction of CuCl2·2H2O with L-
12 alanine and characterized by elemental analysis, spectroscopic methods and single crystal X-ray
13 studies. X-ray analysis indicated that the compound is a 2D coordination polymer which the
carboxylate group of amino acid ligands acts as bridging ligand between Cu(II) ions. The crystal
structure of compound is stabilized by intermolecular hydrogen bond interactions. Magnetic
susceptibility data of powdered sample between 2 and 300 K were interpreted in terms of a 2D-
spin model, with weak antiferromagnetic exchange-coupling through syn-anti carboxylate
bridges, with coupling constant J = –0.2 cm-1 between nearest-neighbor Cu(II) ions. The results
are compared with those obtained from similar studies in other copper amino acid complexes.
2DFT studies showed that overlap of magnetic d x 2 − y 2 orbitals of the neighboring Cu(II) ions and
the molecular orbitals of bridging carboxylate groups is negligible what makes only weak
antiferromagnetic interaction between them. Thermal gravimetric analysis (TGA) indicated that
the compound is stable up to 240 oC and it converts to CuO at about 800 oC. Cyclic voltammetry studies showed a quasi-reversible redox and an irreversible peaks which can be attributed to Cu(I)/Cu(II) and Cu(II)/Cu(III) couples, respectively.
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