Spectroscopic and DFT Study on the Interaction System of Vanadium with l-Proline in Aqueous Solution

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• 作者：Birong Zeng ; Tonghao Shen ; Anan Wu ; Shuhui Cai ; Xianyong Yu ; Xin Xu ; Zhong Chen
• 刊名：Journal of Physical Chemistry A
• 出版年：2010
• 出版时间：April 22, 2010
• 年：2010
• 卷：114
• 期：15
• 页码：5211-5216
• 全文大小：153K
• 年卷期：v.114,no.15(April 22, 2010)
• ISSN：1520-5215

文摘

To gain more insight into the interactions between vanadium and l-proline, the dynamic transformation of the reaction system of vanadium with l-proline and the coordination structures of the vanadium-containing products in 0.15 mol/L NaCl ionic medium mimicking physiological conditions were explored by multinuclear (¹H, ¹³C, ⁵¹V) NMR, ESR, ESI-MS as well as density functional theory (DFT) calculations. Spectroscopic evidence and computational results showed that a monoperoxovanadium species [VO(O₂)(l-proline)₂]⁻ was a major product, where l-proline coordinated to vanadium via nitrogen and oxygen atoms in a bidentate manner to form a distorted pentagonal bipyramidal structure. The species [VO(O₂)(l-proline)₂]⁻ underwent chemical changes in solution at room temperature, finally leading to the reduction of vanadium(V) to vanadium(IV) and the formation of [VO(l-proline)₂]. In the tetrahedral structure of the reduction product [VO(l-proline)₂], l-proline also coordinated to vanadium in a bidentate manner. Such an investigation may be helpful for a better understanding of vanadium complexes as insulin-enhancing agents for the treatment of diabetes.