Intervalence charge transfer in hybrid organic-inorganic neutral radicals

PHYS 524

Lisa N. Perlson, lperlson@stanford.edu1, Imma Ratera2, Christian Sporer2, Jaume Veciana2, and Steven G. Boxer, sboxer@stanford.edu1. (1) Department of Chemistry, Stanford University, Stanford, CA 94305, (2) Institut de Ciencia de Materials de Barcelona, Universitari de Bellaterra, Catalonia, E08913, Spain
Stark spectroscopy is a powerful technique for investigating intervalence charge transfer reactions because it provides a direct measurement of the charge transfer distance. In addition, by fitting the Stark and absorption spectra to a two-state vibronic coupling model, one can determine the values of coupling, reorganization energy, and energetic asymmetry between the charge transfer states (J. Phys. Chem. A, 108, 1764-1778). We used Stark spectroscopy to investigate charge transfer reactions in a series of ferrocene triphenylmethyl radical donor-acceptor compounds in a variety of media and temperatures with an eye toward their use as molecular switches. We show that 1) transient charge transfer occurs by optical excitation; 2) the barrier to thermal charge transfer is prohibitively large at room temperature (ΔG* >> kT); and 3) the potential energy surfaces for these reactions exhibit only one stable minimum.

Poster Session
7:30 PM-10:00 PM, Wednesday, 13 September 2006 Moscone Center -- Hall D, Poster

8:00 PM-10:00 PM, Monday, 11 September 2006 Moscone Center -- Hall D, Sci-Mix

Division of Physical Chemistry

The 232nd ACS National Meeting, San Francisco, CA, September 10-14, 2006