meso, cic/trans optical activity

[datdat]

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1. meso is diastereomers? or what?

2. cic/trans are gemometric isomers and wondering if they are optically inactive or not

Thanks^^

 

[loveoforganic]

Complete. Sentences. Are. Important.

1. Meso compounds are compounds with 2 or more chiral centers that contain a plane of symmetry.

2. There isn't a rule.

 

[datdat]

Complete. Sentences. Are. Important.

1. Meso compounds are compounds with 2 or more chiral centers that contain a plane of symmetry.

2. There isn't a rule.

sorry, I just wanted to be simple..and thanks..

well, as to 1. I was wondering where I can put meso, or classifcation of meso. is it under diastereomers like geometric isomer? or just one example of configurational isomer?


Thanks

 

[loveoforganic]

It depends what you're comparing it to. (1R,3S)-dichlorocyclohexane would be a diastereomer of (1R,3R)-dichlorocyclohexane, a constitutional isomer of 1,1-dichlorocyclohexane, etc.

 

[nze82]

1. meso is diastereomers? or what?

Meso compounds are compounds that have an internal mirror of symmetry. So, by definition, figure-a is a meso compound. Diastereomers are compounds that have the same configuration at one or more chiral centers, but an opposite configuration at others. Notice that this definition applies, when we compare figure-b to figure-a, because the top carbon retains its S conformation, while the bottom carbon in figure (a) has the exact opposite conformation as the one in figure (b). So, figure-a is the diastereoisomer of figure-b, but it's also a meso compound. Thus, meso compounds can indeed be diastereoisomers.

2. cic/trans are gemometric isomers and wondering if they are optically inactive or not
They could be optically activate.

Thanks^^

Hope this helps!