Deciphering the Mechanism Involved in the Switch On/Off of Molecular Pistons  

作　　者：Peng Liu Xueguang Shao Wensheng Cai 

机构地区：[1]State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin 300071, China [2]Collaborative Innovation Center of Chemical Science andEngineering (Tianjin), Tianjin 300072, China [3]Research Center for Analytieal Sciences, College of Chemistry, Nankai University, Tianjin 300071, China

出　　处：《Chinese Journal of Chemistry》2015年第10期1199-1205,共7页中国化学（英文版）

摘　　要：Manufacturing machines converting energy to mechanical work at the molecular level is a vital pathway to ex- plore the microscopic world. A kind of operable molecular engines, composed offl-cyclodextrin （fl-CD）, aryl, al- kene and amide moiety was investigated using molecular dynamics simulations combined with free-energy calcula- tions. To understand how the integrated alkene double bond controls the work performed on the engines, two alkene isomers of the prototype were considered as two molecular engines. The free-energy profiles delineating the binding process of the amide （Z）- and （E）-isomers for each alkene isomer with 1-adamantanol indicate that for the alkene （E）-isomer, the apparent work performed on the amide bond is 1.6 kcal/mol, while the alkene （Z）-isomer is incapa- ble to perform work. Direct switch on/off of engines caused by the isomerization of the alkene bond was, therefore, witnessed, in line with experimental measurements. Decomposition of the free-energy profile into different compo- nents and structural analyses suggest that the isomerization of the alkene bond controls the position of the aryl unit relative to the cavity of the CD, resulting in the difference among the free-energy profiles and the stark contrast of the work performed on engines.Manufacturing machines converting energy to mechanical work at the molecular level is a vital pathway to ex- plore the microscopic world. A kind of operable molecular engines, composed offl-cyclodextrin （fl-CD）, aryl, al- kene and amide moiety was investigated using molecular dynamics simulations combined with free-energy calcula- tions. To understand how the integrated alkene double bond controls the work performed on the engines, two alkene isomers of the prototype were considered as two molecular engines. The free-energy profiles delineating the binding process of the amide （Z）- and （E）-isomers for each alkene isomer with 1-adamantanol indicate that for the alkene （E）-isomer, the apparent work performed on the amide bond is 1.6 kcal/mol, while the alkene （Z）-isomer is incapa- ble to perform work. Direct switch on/off of engines caused by the isomerization of the alkene bond was, therefore, witnessed, in line with experimental measurements. Decomposition of the free-energy profile into different compo- nents and structural analyses suggest that the isomerization of the alkene bond controls the position of the aryl unit relative to the cavity of the CD, resulting in the difference among the free-energy profiles and the stark contrast of the work performed on engines.

关 键 词：molecular pistons cyelodextrins cis-trans isomerization molecular dynamics simulations 

分 类 号：TP309[自动化与计算机技术—计算机系统结构] Q7[自动化与计算机技术—计算机科学与技术]