title: On the role of interfacial hydrogen bonds in "on-water" catalysis.
abstract: Numerous experiments have demonstrated that many classes of organic reactions exhibit increased reaction rates when performed in heterogeneous water emulsions. Despite enormous practical importance of the observed "on-water" catalytic effect and several mechanistic studies, its microscopic origins remains unclear. In this work, the second generation Car-Parrinello molecular dynamics method is extended to self-consistent charge density-functional based tight-binding in order to study "on-water" catalysis of the Diels-Alder reaction between dimethyl azodicarboxylate and quadricyclane. We find that the stabilization of the transition state by dangling hydrogen bonds exposed at the aqueous interfaces plays a significantly smaller role in "on-water" catalysis than has been suggested previously.
authors.affiliation: Department of Chemistry, University of Paderborn, Warburger Str. 100, D-33098 Paderborn, Germany.
authors.forename: Kristof
authors.initials: K
authors.lastname: Karhan
authors.affiliation: Institute of Physical Chemistry, Johannes Gutenberg University Mainz, Staudinger Weg 7, D-55128 Mainz, Germany.
authors.forename: Rustam Z
authors.initials: RZ
authors.lastname: Khaliullin
authors.affiliation: Department of Chemistry, University of Paderborn, Warburger Str. 100, D-33098 Paderborn, Germany.
authors.forename: Thomas D
authors.initials: TD
authors.lastname: Kühne