Calculations are performed on optimal geometries and relative stabilities of 48 new candidates for the structure of the experimentally identified but as yet uncharacterised C70H36molecule. Three structures with entirely unconjugated π systems, which differ only in the siting of the double bond in each polar pentagon, are more stable than all others by ˜ 45 kJ mol−1in the MNDO model. Localisation alone does not ensure stability, but the low strain of this particular arrangement apparently outweighs the total loss of π delocalisation energy.
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