Higher Pressure

1. Pressure sensing photodimer moleculesChristopher J. Bardeen, University of California-Riverside, DMR 0907310 The research supported by this grant has centered on investigating organic materials that turn light into mechanical work using solid-state photochemical reactions. These materials have potential applications as soft actuators and as photon-fueled engines for nanoscale machines. We recently demonstrated that it is also possible to go in the reverse direction, using mechanical force to “undo” photochemical reactions. By making a highly strained anthracene photodimer, we demonstrated for the first time that molecular carbon-carbon bonds could be broken using mild, isotropic pressure in a polymer matrix. These molecules have potential applications as nanoscopic sensors that can be placed inside carbon materials that are subject to strain. High pressure stabilizes “squeezed” transition state and lowers the barrier for going from PI to BA. Faster Reaction Higher Pressure “Pressure catalyzed bond dissociation in an anthracene cyclophane photodimer,” S. R. Jezowski, L. Zhu, Y. Wang, A. P. Rice, G. W. Scott, C. J. Bardeen, E. L. Chronister, J. Am. Chem. Soc., 134, 7459-7466 (2012).

2. Science outreach to local elementary schoolsChristopher J. Bardeen, University of California-Riverside, DMR 0907310 We have developed outreach lessons that conform to the California State standards for science education. Working with teachers, we have visited 1st, 3rd and 4th grade classrooms at predominantly Hispanic local elementary schools in Riverside, CA. At left is a thank-you card from a 1st grade class. We have directly impacted more than 500 pre-college students over the past 12 months. In collaboration with an undergraduate student organization at UC Riverside, the Young Science Scholars, we are starting a new outreach effort where college students go into classrooms to demonstrate the scientific method and provide mentoring for elementary school students.