L07 Chem 261 Quiz: Conformations of Straight Chain Alkanes
13 Dec 2016
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Therefore, it takes 3. 0 kcal/mol to overcome this barrier to rotation (torsional strain) The in phase (constructive) interaction of these mos is an energetically favorable interaction. The e- in the filled (bonding) mo can go into the new lower energy orbital formed between mos. This is stabilizing/lower in energy b/c in phase. The interaction is pi-like but is not a pi bond. Mlx are rotating around a bond through all possible conformations, can"t isolate a single conformer of ethane. Ethane prefers to be in the energetic valley associated with the low energy staggered conformation. Not as high as totally eclipsed (max steric interactions: = 120 , 240 , the anti or anti-periplanar conformer, lowest energy due to min sterics. Me groups are as far away from each other as possible and no groups/atoms are eclipsed. Ie the 2. 6 kcal/mol barrier crossing through the eclipsed conformer going form anti to gauche.
