Andrew Ingram

Mentors Robert Waymouth and Richard Zare

Project Title Direct Detection of Reaction Intermediates

Bio

Andrew grew up locally in San Jose, CA and received a B.S. in Chemistry from San Jose State University, where he studied luminescence and chiroptical properties of lanthanide coordination complexes with Prof. Gilles Muller.  At Stanford, he is a National Science Foundation Graduate Research Fellow and a Robert and Anne T. Bass Stanford Graduate Fellow.  He works jointly in the laboratories of Prof. Robert M. Waymouth and Prof. Richard N. Zare and applies state of the art mass spectrometry, as well as conventional techniques, to mechanistic problems in organometallic catalysis.  

Research Summary

To determine the precise route, or mechanism, of a chemical reaction, studies tend to rely on the creativity and experience of practitioners to envision plausible intermediates and correct mechanisms.  When present, unanticipated species and unconsidered routes can be overlooked.  Furthermore, most mechanistic experiments are indirect, where conclusions are inferred from kinetic rate laws and dependences or, when available, synthetic model systems.

Electrospray based mass spectrometry (ES-MS) methods provide another dimension to these traditional techniques by producing direct information regarding the speciation of intermediates in a reaction mixture.  Unexpected species can be identified and characterized directly from solutions, and their roles interrogated by MS methods.  This MS data is not biased by prior knowledge and complete mechanistic proposals must accommodate it as well as the traditional kinetic data and model systems.

We are applying state of the art mass spectrometry, in conjunction with conventional mechanistic techniques, in order to solve significant problems in organometallic catalysis.  Most of our work has focused on the aerobic oxidation of alcohols catalyzed by palladium, where air is used to drive these reactions.  Using a variety of MS techniques we have examined this process in real time at a range of timescales, from milliseconds to hours.  We have gained insight on the process of alcohol oxidation and uncovered an entirely new mechanism for ambient, room temperature oxygen reduction by palladium.  The knowledge can be used to reduce waste streams for the processes and guide the development of other aerobic oxidation reactions.