title: The effect of a complexed lithium cation on a norcarane-based radical clock.
abstract: Density-functional theory (DFT) and ab initio calculations have been used to investigate the effect of a complexed lithium cation on the radical-clock rearrangement of the 2-norcaranyl radical to the 3-cyclohexenylmethyl radical. As found earlier for ring-closing radical clocks, complexation with a metal ion leads to a significant lowering of the barrier to rearrangement. DFT calculations on a model for the norcaranyl clock in cytochrome P450 confirm the two-state reactivity proposal of Shaik et al. and indicate that the porphyrin exerts little or no electrostatic effect on the rearrangement barrier.
authors.affiliation: Computer Chemie Centrum, Friedrich-Alexander Universität Erlangen-Nürnberg Nägelsbachstrasse 25, 91052 Erlangen, Germany.
authors.forename: Christof M
authors.initials: CM
authors.lastname: Jäger
authors.forename: Matthias
authors.initials: M
authors.lastname: Hennemann
authors.forename: Timothy
authors.initials: T
authors.lastname: Clark