Chun Byeong Jae, Lu Jie, Weck Marcus, Jang Seung Soon
School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, 311 Ferst Drive NW, Atlanta, Georgia 30332-0100, USA and Computational NanoBio Technology Laboratory, School of Materials Science and Engineering, Georgia Institute of Technology, 771 Ferst Drive NW, Atlanta, Georgia 30332-0245, USA.
Department of Chemistry, New York University, 100 Washington Square East, New York, New York 10003, USA.
Phys Chem Chem Phys. 2015 Nov 21;17(43):29161-70. doi: 10.1039/c5cp03854e.
The hydrolytic kinetic resolution (HKR) of epoxides has been performed in a shell-crosslinked micellar (SCM) nanoreactor consisting of amphiphilic triblock copolymers based on poly(2-oxazline)s polymer derivatives with attached Co(iii)-salens to the micelle core. To investigate the effect of the molecular interaction of reactant/product molecules with the SCM nanoreactor on the rate of HKR, we calculated the Flory-Huggins interaction parameters (χ) using the molecular dynamics simulation method. For this, the blend systems were constructed with various compositions such as 15, 45, and 70 wt% of the reactant/product molecules with respect to the polymers such as poly(2-methyl-2-oxazoline) (PMOX), poly(2-(3-butinyl)2-oxazoline) (PBOX), and poly(methyl-3-oxazol-2-yl)pentanoate with Co(iii)-salen (PSCoX). From the χ parameters, we demonstrate that the miscibility of reactants/products with polymers has a strong correlation with the experimental reaction rate of the HKR: phenyl glycidyl ether (Reac-OPh) > epoxyhexane (Reac-C4) > styrene oxide (Reac-Ph) > epichlorohydrin (Reac-Cl). To validate this finding, we also conducted the potential of mean force analysis using steered molecular dynamics simulation for the molecular displacement of Reac-Cl and Reac-OPh through PMOX and PSCoX, revealing that the free energy reduction was greater when Reac-OPh molecule enters the polymer phase compared to Reac-Cl, which agrees with the findings from the χ parameters calculations.
环氧化合物的水解动力学拆分（HKR）是在一种壳交联胶束（SCM）纳米反应器中进行的，该反应器由基于聚（2-恶唑啉）的两亲性三嵌段共聚物组成，这些聚合物衍生物在胶束核心处连接有Co(iii)-salen。为了研究反应物/产物分子与SCM纳米反应器的分子相互作用对HKR速率的影响，我们使用分子动力学模拟方法计算了弗洛里-哈金斯相互作用参数（χ）。为此，构建了各种组成的共混体系，例如相对于聚合物，如聚（2-甲基-2-恶唑啉）（PMOX）、聚（2-（3-丁炔基）-2-恶唑啉）（PBOX）和带有Co(iii)-salen的聚（甲基-3-恶唑-2-基）戊酸酯（PSCoX），反应物/产物分子的含量分别为15%、45%和70%（重量）。根据χ参数，我们证明反应物/产物与聚合物的混溶性与HKR的实验反应速率有很强的相关性：苯基缩水甘油醚（Reac-OPh）>环氧己烷（Reac-C4）>氧化苯乙烯（Reac-Ph）>环氧氯丙烷（Reac-Cl）。为了验证这一发现，我们还使用引导分子动力学模拟对Reac-Cl和Reac-OPh通过PMOX和PSCoX的分子位移进行了平均力势分析，结果表明，与Reac-Cl相比，当Reac-OPh分子进入聚合物相时，自由能降低更大，这与χ参数计算的结果一致。
