ORGN 36 |
| We have computationally studied the effect of steric bulk on the Pd(0)-catalyzed activation of alkane C-H bonds. Interestingly, introducing methyl substituents at the C-H bond causes the latter to become weaker but, nevertheless, the barrier for its activation increases. To understand this behavior, we used an extended variant of our Activation Strain model. In this model the relative energy ΔE of the reaction system is decomposed, along the entire reaction coordinate, into the strain of the reactants ΔEstrain and their mutual interaction ΔEint, see illustration (black: Pd + methane, blue: Pd + methylpropane). By employing this model trends (both the more pronounced and the subtle ones) in the height and position along the reaction coordinate of transition states could be explained in a transparent and straightforward manner.
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Physical Organic Chemistry: Calculations, Mechanisms, Photochemistry, and High-Energy Species
8:00 AM-11:40 AM, Sunday, 10 September 2006 Moscone Center -- Room 133, Oral
Division of Organic Chemistry |
