Title of article :
Ab initio and density functional study of the 5-pentacyclo[6.2.1.13,6.02,7.04,10]dodecyl cation. A symmetrical μ-hydride bridged carbocation
Author/Authors :
Carneiro، نويسنده , , José Walkimar de M. and Taft، نويسنده , , Carlton A. and de Paula e Silva، نويسنده , , Carlos H.T. and Tostes، نويسنده , , José Glauco R. and Seidl، نويسنده , , Peter R. and Pinto، نويسنده , , Paulo Sérgio da S. and Costa، نويسنده , , Valentim Em??lio U. and Alifantes، نويسنده , , Jo?o، نويسنده ,
Abstract :
MP2/6-31g(d,p) and B3LYP/6-31g(d,p) calculations for the pentacyclo[6.2.1.13,6.02,7.04,10]dodecyl cation reveal two minima on the potential energy surface. The most stable minimum is the μ-hydride bridged cation 2. The second minimum is the two-electron three-center bonded structure 3. At MP2/6-31g(d,p) 2 is only 0.2 kcal/mol more stable than 3, but at B3LYP/6-31g(d,p) this energy difference increases to 3.3 kcal/mol. The energy difference between 2 and 3 is only 3.8 kcal/mol. Solvent effect does not affect these numbers significantly. This low energy barrier may account for the product distribution observed on solvolysis of pentacyclic derivatives.
