PHYS 349 |
| Photoexcitation of alkylcobalamins in the visible and near ultraviolet results in the rapid formation of an alkyl radical and a cob(II)alamin radical with unit or near unit quantum yield. The photolysis pathways of several alkylcobalamins have been characterized in both water and ethylene glycol at room temperature. The availability of a clear spectroscopic signature for the dissociation and recombination of the geminate radical pair now allows for a detailed investigation of the dynamics of geminate recombination and cage escape. We have exploited this signature to use a combination of solvent polarity, viscosity, and temperature as parameters to investigate the role of the solvent in the radical cage escape subsequent to the photolysis of adenosylcobalamin, propylcobalamin, ethylcobalamin, and methylcobalamin in water, ethylene glycol, and mixtures of water and ethylene glycol. The results are not consistent with simple continuum models considering radical size and solvent viscosity as the key parameters. |
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PHYS Poster Session - Optical Probes of Dynamics in Complex Environments
7:30 PM-10:00 PM, Wednesday, April 9, 2008 Morial Convention Center -- Hall A, Poster
Division of Physical Chemistry |