Theoretical study on structure, conformation, stability and electronic transition of C4 and C5 anions of ascorbic acid stereoisomers

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• 作者：Hossein A. Dabbagh ; Fatemeh Azami ; Hossein Farrokhpour ; Alireza Najafi Chermahini
• 关键词：Vitamin C stereoisomers ; Conformational analysis ; TD-DFT ; MP2 ; Potential energy surface scan ; Ascorbic acids anions
• 刊名：Journal of Molecular Structure
• 出版年：5 March, 2014
• 年：2014
• 卷：1061
• 期：Complete
• 页码：69-75
• 全文大小：1576 K

文摘

The structures, stabilities, conformational analysis and electronic transitions of l-ascorbic acid anions (four stereoisomers) were studied theoretically. These anions are produced from the de-protonation of C4-H and C5-H sites of l-ascorbic acid stereoisomers. The geometries of these anions were fully optimized in gas phase and aqueous phase in order to determine their relative stabilities. It was observed that the de-protonation at C5 site of two stereoisomers leads to the ring opening in both phases. Isomerization of the l-form to one of the d-form was observed during the optimization of the anions at C5. Conformational analysis (potential energy surface scan) of the opened ring anions was performed in search of energy minima and/or maxima. The absorption electronic transitions of the anions in the UV region were calculated using Time-Dependent Density Functional Theory (TD-DFT).