Jeffrey J. Rack : Molecules in Motion : Isomerization and Photomechanical Effects in Photochromic Ruthenium Sulfoxide Complexes


Jeffrey J. Rack, Department of Chemistry,
Ohio University, Athens, OH 45701

Salle de séminaire du 3ème étage, Bât. 3R1B4, 14h00

Abstract :
Photochromic compounds are light-activated molecular switches that convert photonic energy to potential energy for specific and selective excited state bond breaking and bond making reactions. Our examination of ruthenium and osmium polypryridine complexes containing sulfoxide ligands demonstrate that S-to-O isomerization is efficient, and can occur rapidly both in the solid state and solution. Picosecond transient absorption spectroscopic data show that S-to-O isomerization time constants may be as fast as 45 ps. Recent studies of ruthenium polypyridine complexes containing chelating sulfoxides illustrate that two different colors of light may be used to trigger between the two ground states. Incorporation of these photochromic compounds within polymers leads to an uncommon photomechanical effect, where the polymer undergoes a macroscopic shape deformation upon irradiation. These results and others will be presented and discussed.


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