| Budget Amount *help |
¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 2003: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2002: ¥2,300,000 (Direct Cost: ¥2,300,000)
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| Research Abstract |
We showed that the five-membered ring is the most stable of the monocylic molecules (XH)n (XN,P,As) composed of the 15 group elements and designed mono-and polycyclic molecules with low strains.
A lone pair of an atom in the 15 group delocalize in a cyclic manner since the phase of the n-orbital for the lone pairs and the σ^*-orbitals of the vicinal X-X bonds is continuous. The bond model analysis showed that n-σ^* interaction does not contribute to significant stabiizization for X=N but for X=P and As. The five membered ring is more strained than the six-membered ring for X=N. To our surprise, the five-membered rings (X=P and As) have negative strain energies, and are less strained than the six-membered rings. According to the pentagon stability, we designed polycycic molecules of P and As with low strains.
We showed the pentagon stability of the chemical species, aluminum anion, carbene, silylene, and germylene, where an carbon atom of cyclopentane is replaced by the corresponding atom.
The pentagon stability is shown for the transition states of chemical reactions. For example, the activation energy (4.25) kcal/mol) of the deprotonation from cyclopentane is lower than that (4.52 kcal/mol) from cyclohexane.
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