Bishop's University (Quebec, Canada)
Dalhousie University (Nova Scotia, Canada)
Research Group of Prof. Devens Gust
Arizona State University
Physical organic chemistry
laser flash photolysis
chemistry of materials
Currently, three projects are under investigation the Keirstead research group at UNE. Each project employs a photochemical probe reaction that was selected to learn more about the physicochemical properties of ionic liquids. Ionic liquids (ILs) are thought to be "green" alternatives to conventional solvents for chemical processes and could be employed in nanotechnology devices.
1) Quantifying the cage effect of ionic liquids using the photo-Fries reaction.
The goal of this project is to learn more about the "cage effect" of ILs, or how ILs "restrict" species within a solvent cage. A large cage effect could reduce the efficiency of a photovoltaic cell that uses an IL as the electrolyte, or could influence the product distribution of a chemical reaction.
2) Examining the photochromism of spiropyrans in ionic liquids using emission spectroscopy.
To explore the feasibility of using ILs as solvents for molecular devices, we are examining the dynamics of spiropyran photochromism in ILs. Spiropyrans are a class of photochromic "on-off" molecular switches that could be used as molecular electronic devices. We have used emission spectroscopy to show that the dynamics of the switch are slowed in ILs compared to molecular solvents, due to the unique properties of ILs. Specifically, our system could be used as a robust two-color (red and blue) emitting molecular switch.
3) Investigating the influence of ionic liquid media on the photoluminescence of siloles (with Jerry Mullin, UNE and Hank Tracy, USM).
Siloles are a class of substituted silacyclopentadienyl molecules that are thought to have applications as sensors and luminescent optoelectronic devices, e.g., OLEDs. Siloles typically have low fluorescence quantum yields when dissolved in organic solvents, but their emission increases when in a viscous or polar medium. In this project, we are investigating how the unique properties of ILs influence the photoluminescence of siloles, and in turn, more about the physicochemical properties of ILs.
My research program uses photochemical probe reactions to learn about the properties of novel materials for use in green chemistry and nanotechnology applications. While my current focus is on ionic liquids, I am also interested in other heterogeneous media such as zeolites and metal-organic frameworks (MOFs).
1,1-Dimethyl-2,3,4,5-tetraphenylsilole as a Molecular Rotor Probe to Investigate the Microviscosity of Imidazolium Ionic Liquids. Scalise, Regina E.*; Caradonna, Peter A.*; Tracy, Henry J.; Mullin, Jerome L.; Keirstead, Amy E. Journal of Inorganic and Organometallic Polymers and Materials 2014, 24 (2), 431-441. (*UNE undergraduate students)
Direct observation of spiropyran phosphorescence in imidazolium ionic liquids. Naughton, Sean P.*; Gaudet, Robyn M.*; Leslie, Anne A.*, Keirstead, Amy E. Chemical Physics Letters 2013, 556, 102-107. (*UNE undergraduate students)
2010: "Exploring the Influence of Organized Media on the Photoluminescence Behavior of Siloles" ($25,000/1 year), funded by the Maine Space Grant Consortium Maine Space Grant Education and Seed Research Program (MSG/ESR). With co-PIs Jerome Mullin (UNE) and Hank Tracy (USM).
2011: "Using the photo-Fries reaction as a photochemical probe to quantify the cage effects of ionic liquids" ($50,000/2 years) from the American Chemical Society Petroleum Research Fund.
2012: MRI: Acquisition of a Gas Chromatography-Mass Spectrometry Instrument for Research and Teaching. Ursula Roese PI; with co-PIs Amy Deveau, Teresa Dzieweczynski, Amy Keirstead and Stephan Zeeman ($137,527/2 years) from the National Science Foundation.