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Phys Chem Chem Phys. 2015 Nov 21;17(43):29161-70. doi: 10.1039/c5cp03854e.

Characterization of molecular association of poly(2-oxazoline)s-based micelles with various epoxides and diols via the Flory-Huggins theory: a molecular dynamics simulation approach.

Author information

1
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. SeungSoon.Jang@mse.gatech.edu.
2
Department of Chemistry, New York University, 100 Washington Square East, New York, New York 10003, USA.
3
Computational NanoBio Technology Laboratory, School of Materials Science and Engineering, Georgia Institute of Technology, 771 Ferst Drive NW, Atlanta, Georgia 30332-0245, USA. SeungSoon.Jang@mse.gatech.edu and Institute for Electronics and Nanotechnology, Georgia Institute of Technology, Atlanta, GA, USA.

Abstract

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.

PMID:
26463559
DOI:
10.1039/c5cp03854e
[Indexed for MEDLINE]

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