Do cis/trans isomers have similar chemical properties?

[tym]

Do cis/trans isomers have similar or different chemical properties? I saw conflicting answers to this question:

"Cis/ trans isomers alsohave similar chemical properties but different physical properties." (http://chemed.chem.purdue.edu/genchem/topicreview/bp/1organic/isomers.html)

"Cis/trans isomers have different chemical and physical properties and can exhibit dramatically different biological activity." (http://en.wikibooks.org/wiki/Organic_Chemistry/Chirality/Diastereomers#Cis-trans_Isomerism)

Which one is right? (Or more right for the purpose of the MCAT?) Thanks.

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[sillyjoe]

Depends. The constituents are very important. A trans isomer can be non-polar while a cis isomer can be VERY polar. This would change both the chemical and physical properties.

To my understanding, it would be very hard to make a global generalization about this.

 

[Mantis Toboggin]

Here's how Kaplan taught it, and how I think of it.

Cis/trans isomerism is a form of diastereomerism. Diastereomers have different physical AND chemical properties. Therefore I'd think that they'd have different phys/chemical properties.

As the poster above said, the groups attached are important to determine polarity. For example, cis alkenes have higher boiling points due to intermolecular forces. Trans alkenes have higher melting points.

 

[Mantis Toboggin]

Sorry to double post but this is something that has been bothering me, related to this.

The distinction between Cis/trans and e/z is that the former involves the same substs. On both sides whereas the latter my have different on both sides.

So I'm assuming that if we wanted to estimate the phys properties of e/z we would pay attention to the net polarity of the molecule, same as CIs/trans and work from there?