Chemistry and Chemical Physics Graduate Programs brochure

ROBERT S. SHERIDAN
Professor
Organic Chemistry
E-mail: rss@unr.edu
28 - Faculty
B.S. (1974), Iowa State University; Ph.D. (1979),
University of California, Los Angeles (O.L. Chapman), NSF
Predoctoral Fellow; NIH Postdoctoral Fellow (1979-80),
Yale University (J.A. Berson); Foundation Professor,
University of Nevada, Reno (2001-03).
Our research revolves around highly reactive organic molecules. These
unstable and elusive intermediates, such as carbenes, nitrenes, and biradicals,
are especially important in photochemistry, but their chemistry and
properties are poorly understood. Moreover, these molecules are related
to searches for organic conducting and magnetic materials. Much of the
organic synthesis that we carry out involves making previously unknown
compounds, and we spend a considerable amount of our time developing
new synthetic methods to tackle these challenging molecules. A specialized
technique that we use to study
reaction intermediates involves matrix isolation
photochemistry. In this method, organic molecules
are frozen into glasses of inert gas at extremely
low temperatures (10 K). The samples are
then irradiated with UV light to generate highly
reactive intermediates. The low temperatures
and high dilution in inert surroundings protect
these otherwise unstable species from reaction.
IR and UV spectra of the samples, acquired at low
temperature, tell us a great deal about the bonding
and structures of the products. Finally, we
carry out a variety of ab initio and DFT electronic
structure calculations to model the structures,
spectra, and electronics of these novel molecules.
Our recent work has focused on three major
areas: (1) investigations of carbenes important
in biological photoaffinity labeling, (2) highly strained organic molecules, and (3) quantum
mechanical tunneling in reactive intermediates.
Selected Publications
1. “Quantum mechanical tunneling in organic reactive intermediates,” Sheridan, R.S., in Reviews
in Reactive Intermediate Chemistry, R.A. Moss, M.S. Platz, and M.J. Jones, Jr., Ed., John Wiley &
Sons, 2007, pp 415 – 463.
2. “A singlet aryl-CF carbene: 2-Benzothienyl(trifluoromethyl)carbene and interconversion
3
with a strained cyclic allene,” Wang, J.; Sheridan, R.S. Org. Lett. 2007, 9, 3177 – 3180.
3. “Conformational product control in the low-temperature photochemistry of cyclopropylcarbenes,”
Zuev, P.S.; Sheridan, R.S.; Sauers, R.R.; Moss, R.A.; Chu, G. Org. Lett. 2006, 8, 4963.
4. “Kinetic studies of the cyclization of singlet vinylchlorocarbenes,” Moss, R.A.; Tian, J.; Sauers,
R.R.; Sheridan, R.S.; Bhakta, A.; Zuev, P.S. Org. Lett. 2005, 7, 4645.
5. “Geometry and aromaticity in highly strained heterocyclic allenes: Characterization of a
2,3-didehydro-2H-thiopyran,” Nikitina, A.; Sheridan, R.S. Org. Lett. 2005, 7, 4467.
6. “Activation energies for the 1,2-carbon migration of ring-fused cyclopropylchlorocarbenes,”
Chu, G.; Moss, R.A.; Sauers, R.R.; Sheridan, R.S.; Zuev, P.S. Tetrahedron Lett. 2005, 46, 4137.
7. “Singlet Vinylcarbenes: Spectroscopy and Photochemistry,” Zuev, P. S.; Sheridan, R. S. J. Am.
Chem. Soc. 2004, 126, 12220.