Sigma Bond Rotation

As we’ve learned before, single bonds have the ability to freely rotate, meaning that we have to get used to seeing multiple arrangements of single bonds and understanding that they are all the same thing. 

These multiple arrangements are known as conformers.

Notice that the only difference between these was one rotation?

This next one is tricky because it has two rotations in it. See if you can identify them.

Example: Determine if the following pairs of molecules are isomers or conformers 

4m

Remember: If double bonds are switching configuration, that’s an isomer. If single bonds are rotating, that a conformer. 

Example: Determine if the following pairs of molecules are isomers or conformers 

2m

One more, hopefully these are getting a little easier!

Example: Determine if the following pairs of molecules are isomers or conformers 

3m

We’ll be rotating double bonds all the time in this course, so I’m hoping by now you are more comfortable recognizing that multiple rotations really equal to the same thing.