Axial - Equatorial (larger view)
Axial - Equatorial (larger view)
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cis-1,4-Dimethylcyclohexane
What is the difference in energy between the two chair conformations of cis-1,4-dimethylcyclohexane? Cis-1,4-substitution in a chair cyclohexane means that one group (methyl) must be equatorial and the other axial [Review]. The left hand structure has an axial blue methyl group and the an equatorial red methyl group. A chair-chair interconversion merely switches the position of the two groups: equatorial ---> axial; axial ---> equatorial. The right hand structure has a red axial methyl group and a blue equatorial methyl group. Therefore, ΔGo = 0 kcal/mol and Keq = 1 for the two chair conformations. The total energy for each chair conformation is 1.8 kcal/mol.
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<SCRIPT LANGUAGE="">jmolInitialize("../../jmol"); // REQUIRED
jmolApplet(300, "load ../../jmol/movies/dimecyclhex-1,4-cis-1.mol; select hydrogen; color atoms yellow;\
select atomno=4; color atoms red; select atomno=8; color atoms blue; select atomno=1, atomno=2, atomno=3, atomno=5, atomno=6, atomno=7;\
color atoms gray; select all;spin off; set spin y 20; set spin z 20")</SCRIPT></FONT>
<P><FONT SIZE="+1" COLOR="#0000FF">Axial</FONT><FONT SIZE="+1">-</FONT><FONT SIZE="+1" COLOR="#FF0000">Equatorial</FONT><FONT SIZE="+1">
(</FONT><A HREF="dimecyclohex-1,4-cis1F.html"><FONT SIZE="+1">larger
view)</FONT></A></P></CENTER>
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<SCRIPT LANGUAGE="" src="../../jmol/Jmol.js"></SCRIPT> </head>
<SCRIPT LANGUAGE="">jmolInitialize("../../jmol"); // REQUIRED
jmolApplet(300, "load ../../jmol/movies/dimecyclhex-1,4-cis-1.mol; select hydrogen; color atoms yellow;\
select atomno=4; color atoms blue; select atomno=8; color atoms red; select atomno=1, atomno=2, atomno=3, atomno=5, atomno=6, atomno=7;\
color atoms gray; select all;spin off; set spin y 20; set spin z 20")</SCRIPT></FONT>
<P><FONT SIZE="+1" COLOR="#FF0000">Axial</FONT><FONT SIZE="+1">-</FONT><FONT SIZE="+1" COLOR="#0000FF">Equatorial</FONT><FONT SIZE="+1" COLOR="#FFFFFF">
</FONT><FONT SIZE="+1">(</FONT><A HREF="dimecyclohex-1,4-cis2F.html"><FONT SIZE="+1">larger
view</FONT></A> <FONT SIZE="+1">)</FONT></P></CENTER>
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