Roseanne Sension

Light, Molecules, Action.

Light provides a versatile energy source capable of precise manipulation of material systems on size scales ranging from molecular to macroscopic. Photochemistry provides the means for harnessing light energy through the movement of charge, a change in molecular shape, or the cleavage of a bond. Photochemistry produces action. The potential for optically powered molecular devices covers a wide range of applications, from motors, and switches, to sensors and delivery platforms. Cobalamins and other cyclic tetrapyrroles can provide spatial and temporal control of radical formation, charge transfer, and drug delivery. Water soluble photoacids are capable of providing control of the local pH on an ultrashort time scale.

The practical development of optically controlled molecular devices faces a range of challenges. In our group we use time-resolved spectroscopic methods coupled with theoretical simulations to investigate, predict, and control the photochemistry of important light-activated transformations. Femtosecond transient absorption spectroscopy in the UV-visible region of the spectrum is used to characterize time-scales and monitor product formation. State-of-the-art femtosecond X-ray studies carried out at X-ray free electron laser facilities such as LCLS at SLAC allow the direct observation of structural evolution beginning at the very earliest times.

Representative Publications

Wiley, T.E., Konar, A., Miller, N.A., Spears, K. G. and Sension R. J., 2018, “Primed for Efficient Motion: Ultrafast Excited State Dynamics and Optical Manipulation of a Four Stage Rotary Molecular Motor” Journal of Physical Chemistry A, v122, 7548-7558. DOI:10.1021/acs.jpca.8b06472

Wiley, T.E., Miller, N.A., Miller, W. R., Sofferman, D., Lodowski, P., Toda, M. J., Jaworska, M., Kozlowski, P. M. and Sension, R. J., 2018, “Off to the races: Comparison of excited state dynamics in vitamin B12 derivatives hydroxocobalmin and aquocobalamin” Journal of Physical Chemistry A, v122, 6693-6703. DOI: 10.1021/acs.jpca.8b06103

Miller, N.A., Deb, A., Alonso-Mori, R., Glownia, J.M., Kiefer, L.M., Konar, A., Michocki, L., Sikorski, M., Sofferman, D., Song, S., Toda, M.J., Wiley, T.E., Zhu, D., Kozlowski, P.M., Kubarych, K.J., Penner-Hahn, J.E. and Sension, R.J. 2018, “Ultrafast X-Ray Absorption Near Edge Structure Reveals Ballistic Excited State Structural Dynamics” Journal of Physical Chemistry A, v122, 4963-4971. DOI: 10.1021/acs.jpca.8b04223

Miller, N.A., Deb, A., Alonso-Mori, R., Garabato, B.D., Glownia, J.M., Kiefer, L.M., Koralek, J., Sikorski, M., Spears, K.G., Wiley, T.E., Zhu, D., Kozlowski, P.M., Kubarych, K.J., Penner-Hahn, J.E. and Sension, R.J. 2017, “Polarized XANES Monitors Femtosecond Structural Evolution of Photoexcited Vitamin B12.”  Journal of the American Chemical Society, v139, 1894-1899. DOI: 10.1021/jacs.6b11295

Miller, N.A., Wiley, T.E., Spears, K.G., Ruetz, M., Kieninger, C., Kräutler, B., and Sension R.J., 2016, “Toward the Design of Photoresponsive Conditional Antivitamins B12: A Transient Absorption Study of the Photochemistry of an Arylcobalamin and an Alkynylcobalamin.”  Journal of the American Chemical Society, v138, 14250-14256. DOI: 10.1021/jacs.6b05299 

Smith, B. D., Spears, K. G., and Sension, R. J., 2016, “Probing the Biexponential Dynamics of Ring-Opening in 7-Dehydrocholesterol.”  Journal of Physical Chemistry A, v120, 6575-6581. DOI: 10.1021/acs.jpca.6b06967

Wiley, T. E., Miller, W. R., Miller, N. A.,  Sension, R. J., Lodowski, P., Jaworska, M., Kozlowski, P. M., 2016, “Photostability of Hydroxocobalamin: Ultrafast Excited State Dynamics and Computational Studies” Journal of Physical Chemistry Letters. v7, 143-147. DOI: 10.1021/acs.jpclett.5b02333 

Rury, A.S., Wiley, T.E., and Sension R. J. 2015 “Energy cascades, excited state dynamics, and photochemistry in cob(III)alamins and ferric porphyrins.” Accounts of Chemical Research, v48, 860-867. DOI: 10.1021/ar5004016

Arruda, B. C. and Sension, R. J. 2014 “Ultrafast polyene dynamics: The ring opening of 1,3-Cyclohexadiene Derivatives” Physical Chemistry Chemical Physics, v16, 4439 - 4455. DOI: 10.1039/C3CP54767A 

Research Areas(s)

• Bioinorganic Chemistry
• Biophysical Chemistry
• Chemical Biology
• Energy Science
• Optics and Imaging
• Physical Chemistry
• Sustainable Chemistry
• Ultrafast Dynamics
• Ultrafast Laser Spectroscopy and Chemical Reaction Dynamics

Award(s)

• Mildred Dresselhaus Award, CUI-Hamburg, 2014
• American Physical Society Fellow, 2007
• LSA Excellence in Education Award, 2005