The scope of organic photochemistry has been significantly broadened through reactions that proceed via electron transfer.
The dynamics of radical ion pairs (contact and solvent-separated) and the factors that control their radiative and nonradiative
decay provided a framework to design efficient photoinduced electron transfer reactions. Investigating these reactions relied
on the combined use of several transient and steady state kinetics. Current interest is on electron transfer reactions that
take place only when coupled with a chemical transformation (e.g., bond cleavage, bond formation or proton transfer). Careful
examination of several reactions revealed that these bond-coupled electron transfer reactions (uni-, bi-, and ter-molecular) are
not uncommon. A second theme of the current research is on quantum amplification. Very high quantum yields were achieved in complex
chain reactions involving free radicals that proceed via electron transfer, as well as those propagated via adiabatic reactions
in the triplet state.
Relevant Publications
Gillmore, J.G., Neiser, J.D., McManus, K.A., Roh, Y., Dombrowski, G.W., Brown, T.G., Dinnocenzo, J.P., Farid, S., Robello, D.R.
"Quantum Amplified Isomerization: A New Concept for Polymeric Optical Materials,"
Macromolecules
2005,
38,
7684-7694.
Shukla, D., Ahearn, W.G., Farid, S.
"Chain Amplification in Photoreactions of N-Alkoxypyridinium Salts with Alcohols: Mechanism and Kinetics,"
J. Org. Chem.
2005,
70,
6809-6819.
Dombrowski, G.W., Dinnocenzo, J.P., Zielinski, P.A., Farid, S., Wosinska, Z., Gould, I.R.
"Efficient Unimolecular Deprotonation of Amine Radical Cations,"
J. Org. Chem.
2005,
70,
3791-3800.
Gould, I.R; Lenhard, J.R., Farid, S.
"A Curve-Crossing Model for Oxidative Decarboxylation. Kinetics of Anilino Carboxylate Fragmentation,"
J. Phys. Chem. A
2004,
108,
10949-10956.
Shukla, D; Young, R.H., Farid, S.
"Reducing Power of Photogenerated α-Hydroxy Radicals. Proton-Coupled Electron Transfer,"
J. Phys. Chem. A
2004,
108,
10386-10394.
Wang, Y., Luttrull, D.K., Dinnocenzo, J.P., Goodman, J.L., Farid, S., Gould, I.R.
"Associative Return Electron Transfer. A Bond-Coupled Electron Transfer in the Photoreactions of Cyclopropylamines,"
Photochem. Photobiol. Sci.
2003,
2,
1169-1176.
Gould, I.R., Boiani, J.A., Gailard, E.B., Goodman, J.L., Farid, S.
"Intersystem Crossing in Charge-Transfer Excited States,"
J. Phys. Chem. A
2003,
107,
3515-3524.
Gould, I.R., Shukla, D., Giesen D., Farid, S.
"Energetics of Electron-Transfer Reactions of Photoinitiated Polymerization: Dye-Sensitized Fragmentation of N-Alkoxypyridinium Salts,"
Helv. Chim. Acta
2001,
84,
2796-2812.
Gould, I.R., Lenhard, J.R., Muenter, A.A., Godleski, S.A., Farid, S.
"Two-Electron Sensitization: A New Concept for Silver Halide Photography,"
J. Am. Chem. Soc.
2000,
122,
11934-11943.
Dockery, K.P., Dinnocenzo, J.P., Farid, S., Goodman, J.L., Gould, I.R., Todd, W.P.
"Nucleophile-Assisted Cleavage of Benzyltrialkylsilane Cation Radicals,"
J. Am. Chem. Soc.
1997,
119,
1876-1883.
