Qian Xianghong
Department of Chemical Engineering, University of Arkansas , Fayetteville, Arkansas 72701, United States.
J Phys Chem B. 2013 Oct 3;117(39):11460-5. doi: 10.1021/jp402739q. Epub 2013 Sep 13.
Car-Parrinello-based molecular dynamics coupled with metadynamics simulations were used to determine the mechanism and associated free energy surface for opening the ring structure of cyclic glucopyranose in acidic aqueous solutions. The ring-opening process is initiated by the protonation of the ring oxygen atom and the breakage of the C1-O5 bond. The barrier for this process is about 25 kcal/mol, in good agreement with experimental measurements. Moreover, the glucose cyclic conformation is found to be more stable than the open chain form. The barrier for proton-catalyzed ring-opening in aqueous solution appears to be largely solvent induced due to the high affinity of water molecules for protons.
基于Car-Parrinello的分子动力学与元动力学模拟相结合，用于确定酸性水溶液中环状葡萄糖吡喃糖环结构打开的机制及相关自由能面。开环过程由环氧原子的质子化和C1-O5键的断裂引发。该过程的势垒约为25千卡/摩尔，与实验测量结果吻合良好。此外，发现葡萄糖的环状构象比开链形式更稳定。由于水分子对质子的高亲和力，水溶液中质子催化开环的势垒似乎很大程度上是由溶剂诱导的。
