Zhang Xu, Yang Zhanlan, Li Weihong, Yang Limin, Weng Shifu, Wu Jinguang
The State Key Laboratory of Rare Earth Materials Chemistry and Applications, Department of Chemical Biology, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
Spectrochim Acta A Mol Biomol Spectrosc. 2004 Jan;60(1-2):235-40. doi: 10.1016/s1386-1425(03)00224-5.
D,L-Homocysteic acid (DLH), an amino acid in the mammalian central nervous system, can excite the cerebral activities and has been proposed as an agonist of endogenous glutamate receptor. It contains -NH(3)(+), -COOH and -SO(3)(-) groups, therefore, the interactions between DLH and metal ions may be expected. In the present investigation, the complexes of DLH with NH4(+), Li+, Na+ and K+ at different pH conditions were synthesized and characterized by Fourier transform infrared (FT-IR) spectroscopy. It was concluded that the structures of the complexes prepared at pH 2.6 and 4.0 are similar to each other and the C=O groups are mono-dentate coordination for these complexes. However, the structures of the complexes synthesized at pH 13.0 change considerably from the complexes at pH 2.6 and 4.0, which show that dissociation has occurred in aqueous solution. The four cations coordinate to DLH, which result in the rearrangement of the hydrogen bond network and the skeletal structure change of the ligand.
