Understanding Conformational Analysis in the Case of Pentane, Butane and a Particular Naphthalene

Question

Here it goes. Why do you think the energy between a 1,5-Me-Me interaction is lower (3.7 Kcal/mol) than a 1,4-Me-Me interaction in butane (3.1 Kcal/mol)? Why is the energy for a Me-Me interaction in 1,9-napththalene 7.6 Kcal/mol?

Use a molecular kit to answer these questions and think about molecular geometries!

Answer 1

Hi! Make sure you check out my brief video to get the answer right! If you have any questions/suggestions/comments do contact me!

Also, I am attaching a few sources and references that can be useful to understanding these problems further.

Wiberg, K. B.; Murcko, M. A., Rotational barriers. 2. Energies of alkane rotamers. An

examination of gauche interactions. Journal of the American Chemical Society 1988, 110

(24), 8029-8038

Bader, R. F. W.; Cheeseman, J. R.; Laidig, K. E.; Wiberg, K. B.; Breneman, C., Origin of

rotation and inversion barriers. Journal of the American Chemical Society 1990, 112 (18),

6530-6536

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