Campus Units

Chemistry, Ames Laboratory

Document Type

Article

Publication Version

Published Version

Publication Date

12-15-2015

Journal or Book Title

The Journal of Physical Chemistry B

DOI

10.1021/acs.jpcb.5b08446

Abstract

The aldol reaction catalyzed by an amine-substituted mesoporous silica nanoparticle (amine-MSN) surface was investigated using a large molecular cluster model (Si392O958C6NH361) combined with the surface integrated molecular orbital/molecular mechanics (SIMOMM) and fragment molecular orbital (FMO) methods. Three distinct pathways for the carbinolamine formation, the first step of the amine-catalyzed aldol reaction, are proposed and investigated in order to elucidate the role of the silanol environment on the catalytic capability of the amine-MSN material. The computational study reveals that the most likely mechanism involves the silanol groups actively participating in the reaction, forming and breaking covalent bonds in the carbinolamine step. Therefore, the active participation of MSN silanol groups in the reaction mechanism leads to a significant reduction in the overall energy barrier for the carbinolamine formation. In addition, a comparison between the findings using a minimal cluster model and the Si392O958C6NH361 cluster suggests that the use of larger models is important when heterogeneous catalysis problems are the target.

Comments

Reprinted (adapted) with permission from The Journal of Physical Chemistry B, doi: 10.1021/acs.jpcb.5b08446. Copyright 2015 American Chemical Society.

Copyright Owner

American Chemical Society

Language

en

File Format

application/pdf

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