[Mikez]

I was comparing the stability of the 3 isomers of dibenzalacetone and I was stuck on why the E,E isomer was the most stable. How exactly dose conjugation help this isomer be more stable? don't all 3 of the isomers have conjugation to stablize them.

 I know that this isomer allows the phenyl groups to be far away from the ketone group but there is more than just this factor that makes it stable and I having a hard time figuring out what those other factors are.

thanks

[sjb]

I was comparing the stability of the 3 isomers of dibenzalacetone and I was stuck on why the E,E isomer was the most stable. How exactly dose conjugation help this isomer be more stable? don't all 3 of the isomers have conjugation to stablize them.

 I know that this isomer allows the phenyl groups to be far away from the ketone group but there is more than just this factor that makes it stable and I having a hard time figuring out what those other factors are.

thanks

If, as you say all three isomers of dibenzalacetone are equal in terms of conjugation, then perhaps you need to look elsewhere for potential factors that can (de-)stabilise molecules. Typically, these will be sterics.

[Mikez]

thanks,

is the steric strain caused by the 2 phenyl groups
or
the phenyl with the carbonyl group?

If I were to instead rotated around the single bond connecting the phenyl and the carbonyl would the maxima and minimas here be caused by the 2 phenyl grps or
the phenyl with the carbonyl group?

thanks