Local Electric Field Effects on Rhodium-Porphyrin and NHC-Gold Catalysts
Technical Report,30 Sep 2011,30 Sep 2014
The Leland Stanford Junior University Stanford United States
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Controlling the selectivity of catalytic reactions is one of the greatest challenges of synthesizing organic compounds that are essential for health, technology, and defense. The purpose of this project was to investigate the use of externally applied electric fields to control the selectivity of reactions in a way that is complementary to conventional methods. Using a custom reaction vessel, it was shown that the selectivity of reactions that are confined to an insulating electrode-electrolyte interface could be altered by the application of a voltage across the interface. The magnitude of the selectivity changes depended on the charge density that accumulated at the interface, which was controlled by the voltage and the interfacial capacitance. It was proposed that the charge density affects the reaction outcome through local field-dipole interactions with the reacting species themselves andor the surrounding solvent molecules. In a separate set of experiments, it was shown that field-dipole interactions that arise in tight ion pairs could be exploited to control selectivity. The counterion to a reactive complex in a tight ion pair preferentially stabilizes transition states with the largest dipole moments.