1. Conformations of Alkanes Title

2. 3.0 1.0 Eclipsed C-H/C-H interaction = 1.0 kcal/mol 0 120 240 360 180 60 300 Ethane

3. 0 60 120 180 240 300 360 1.3 1.0 3.3 Eclipsed CH 3 /H interaction = 1.3 kcal/mol Propane

4. 300 0.9 240 3.6 180 0, anti 0 60 120 3.6 1.3 1.0 360 5.3 1.0 3.3 1.0 Eclipsed CH 3 /CH 3 interaction = 3.3 kcal/mol 0.9 Gauche CH 3 /CH 3 interaction = 0.9 kcal/mol Butane

5. 2- Methylbuta ne 0 3.3 1.3 1.0 5.6 60 0.9 120 3.9 300 1.8 360 5.6 180 0.9 240 5.6 Highest energy eclipsed conformations Lowest energy staggered conformations Conformation of 2-Methylbutane

6. EtPrBuIsobutG raph Conformational Energy of C 2 - C 5 Acyclic Alkanes Energy (kcal/mol) Dihedral Angle 600180240300360120 2-Methylbutane

7. Cyclohexane chair 10 half chair 10 half chair 5.5 kcal/mol @ 25 o K eq = e -  E/RT K eq = ~10 4 5.5 twist boat 5.5 twist boat 6.9 boat

8. The End Title F. E. Ziegler 2009