XAFS Study of Coordination Structure of Cu(L-His)2 in Solution
- Received Date: 2011-06-01
- X-ray absorption fine structure, Coordination structure, Copper, Histidine, Chemical modification, pH
Abstract: Multiple coordination modes are present in the CuII-histidine complex in solution and the copper coordination environment varies with pH. In this work, we have investigated the coordination geometry of Cu(His)2 complex using X-ray absorption fine structure (XAFS) analysis. Copper K-edge XAFS spectra were acquired on aqueous Cu2+ samples with his-tidine at different pH values. The coordination environments were further confirmed by chemically modified histidine. Results show that the caboxylate groups coordinate at acidic condition, while amino and imidazole nitrogens get coordinated at higher pH. For the co-ordination geometry of Cu(His)2 in solution at physiological pH, the sixfold coordination is preferentially formed, while the fivefold coordination can co-exist in equilibrium.
|Citation:||Yan Pan, Li-yun Zhang, Yang-zhong Liu. XAFS Study of Coordination Structure of Cu(L-His)2 in Solution[J]. Chinese Journal of Chemical Physics , 2011, 24(4): 451-456. doi: 10.1088/1674-0068/24/04/451-456|