ORGN 680 |
| A systematic study has been carried out to understand the mechanistic details of photochemical excitation and addition of water to enhance the reactivity of SmI2. In the first study, bimolecular quenching constants (kq) for SmI2 in the presence of a series of substrates were derived from Stern-Volmer plots. Values of kq paralleled the free energy changes of the photoinduced electron transfer processes and were in good agreement with the electron transfer rate constants (ket) derived from Marcus theory. In the second study, the role of water as an additive to reactions of SmI2 was examined in detail. Water was found to have an unusually high affinity towards Sm(II). Coordination of water was found to alter the mechanistic pathway of reductions. The rate order with respect to water, kinetic isotopic effects (kH/kD) and comparisons with other proton donors are consistent with water being unique among additives containing an O-H bond.
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Physical Organic Chemistry: Calculations, Mechanisms, Photochemistry, and High-Energy Species
1:00 PM-5:00 PM, Wednesday, 16 March 2005 Convention Center -- Room 11A, Oral
Division of Organic Chemistry |
