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Divinylketone: Conformational preferences. Molecular geometry and vibrational force field in the ground state

✍ Scribed by Per N. Skancke

Publisher: John Wiley and Sons
Year: 1983
Tongue: English
Weight: 635 KB
Volume: 4
Category: Article
ISSN: 0192-8651
DOI: 10.1002/jcc.540040204

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✦ Synopsis

The conformational preferences of the molecule 1,4-pentadien-3-one (divinylketone) have been studied by ab initio molecular orbital calculations and discussed in terms of interaction between molecular fragments. The calculations predict a molecular ground state having a fully coplanar s-cis, s-cis conformation. In addition, we find three other structures that represent local minima on the energy surface. These are a fully coplanar s-cis, s-trans form, and two nonplanar s-trans, s-trans forms having symmetries CS and Clh, respectively. The energies of these forms relative to the ground state are 7.5, 19.2, and 35.9 kJ/mol, respectively. The coplanar s-trans, s-trans form represents a saddle point on the energy surface. All conformers and the saddle point have been completely geometry optimized by the gradient technique. For the ground state a complete in-plane harmonic force field has been evaluated.

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