Mechanisms and Dynamics in Homogeneous Catalysis

A bright field (white light illumination) image of toluene droplets surrounded by water on a glass coverslip functionalized with perfluorosilanes. An illustration of that can be seen below.
An overlayed image of bright field (grey/black) droplets and the fluorescence (red-artifical coloring) from single fluorescently labeled molecules inside of them. These microdroplets (<1 um diameter) allow us to investigate single molecules while again pushing the concentration barrier.

Homogeneous catalysis consists of complex pathways which can pass through multiple intermediates to generate the desired product but often can undergo side reactions producing unwanted products or catalyst decomposition. It is necessary to design active and selective catalysts to meet the ever-growing demand of sustainably produced fuels and materials. Understanding the dynamics and mechanism of molecular catalysts is critical for future catalyst designs. Traditional bulk or ensemble-averaged experiments can provide a lot of important mechanistic information. However it’s limited in being able to identify unsynchronized events that can have a major impact on reaction mechanism. These unsynchronized events can be due to heterogeneity within a catalyst population. We aim to use single-molecule fluorescence microscopy to uncover and identify unsynchronized catalyst dynamics directly under reaction conditions. This goal is approached in a variety of ways that include synthesis of fluorescently labeled molecules, development of non-invasive immobilization techniques, and designing new ways to break the concentration barrier for single molecules studies using droplets and nanophotonic devices.