Enantiomerism and Conformation .

[Rishabh123]

Enantiomerism and Conformation... :)

How are enantiomers and conformers of a optically active compund different..??

In other words an enantiomeric pair can e formed y taking a compund that has a chiral centre and preparing a suitable conformer by rotation of bonds then what's the difference... please help guys.

 

[frodft]

I think it's the enantiomer's orientation with respect to the direction that the incident light is polarized in. This will determine how much the enantiomer can rotate the polarized light and in what direction.

I only just learned this stuff in orgo today so don't hold me to it. Any help from anyone else would be much appreciated.

 

[FlavorD]

Wiki: In chemistry, conformational isomerism is a form of stereoisomerism in which the isomers can be interconverted exclusively by rotations about formally single bonds.[1] Such isomers are generally referred to as conformational isomers or conformers and specifically as rotamers[2] when they differ by rotation about only one single bond. Conformational isomers are thus distinct from the other classes of stereoisomers for which interconversion necessarily involves breaking and reforming of chemical bonds. The rotational barrier, or barrier to rotation, is the activation energy required to interconvert rotamers.

Translation: conformers are so similar that they're just differences from rotating around one bond. See http://en.wikipedia.org/wiki/Conformational_isomerism for a diagram example using butane. This makes them different from other types of isomers that would need to break bonds to rearrange the atoms to make the isomers match.

In the diagram examples at http://en.wikipedia.org/wiki/Isomer#Instances_of_Isomerization, the first isomers need actual atom rearrangement to be made to match, not just a bond rotation. A good example of a bond rotation is retinal in your eye: http://books.google.com/books?id=Y2...&q=retinol photoisomerization diagram&f=false. If you read far enough, you find that the photon has weakened a pi bond and allowed the molecule to straighten, which then (if I'm reading this right) presses against another molecule and sends off an electron which ends up triggering the nerve in the eye.