Tricyclo heptyl cation

In a subsequent calculational study [HF and MP2 levels of theory with 6-31G(d) basis set and MP4(SDQ)], Szabo and Cremer849 explored the he C7Hn+ potential energy surface. Cation 487 (tricyclo[4.1,0.01,3]heptyl cation), the protonated ethano-bridged derivative of spirocyclopentyl cation, was considered to be the missing link between the bicyclo[3.2.0]hept-3-yl cation 488 and the 7-norbomyl cation 489. It is a kinetically stabilized species separated from cations 488 and 489 by 18.9 and 15.9 kcal mol-1, respectively. 

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