Abstract:

Photochromic materials reversibly change color upon irradiation. A photochrome is often a pair of isomers with different optical spectra which undergo isomerization in one or both directions upon irradiation. There is great interest in the application of photochromes as demonstrated by research in data storage, holography recording, microfabrication, microfluidic devices, and photoactuators. Application has been limited due to fatigue, low efficiency, and thermal instability. The photochromic response in most cases depends on an isomerization which is inherently assymetric. Thus a more favorable isomerization in one direction often means the complementary (reverse) isomerization is less favorable particularly when a common intermediate is involved. Our lab designs ultrafast organometallic photochromes based on a linkage isomerization. Non-productive processes that compete with a linkage isomerization and strategies to eliminate them will be discussed.

Biosketch:

Professor Burkey obtained a B.S. in Chemistry at Harvey Mudd College, and a Ph.D. at UC San Diego determining linear free energy relationships for unfavorable equilibria of thiol addition to carbonyl compounds. Post doctoral studies at the Hydrocarbon Research Laboratory of the National Research Council Canada included studies of free radicals utilizing modulation spectroscopy, time-resolved ESR spectroscopy, and time-resolved photoacoustic calorimetry. A second postdoctoral appointment at the Louisiana State University focused on investigations of lipid peroxidation initiation by free radicals in second-hand smoke and persistent radicals in lung tissue after exposure to cigarette tar. Since joining the University of Memphis (originally Memphis State University) studies have included thermochemistry and time resolved studies of organometallic intermediates, decomposition mechanisms of energetic materials, and the design of organometallic photochromes.