Cloner
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cis-trans conversions
If a diene exists in the trans configuration, what is needed to get it to become cis?
I am sure there was some reaction involving a 500W mercury lamp somewhere, but I can't find the reference. Does it take light, heat? Time?
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12AX7
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Trans is more favorable, so wouldn't you need a like catalyst or something to make it prefer cis?
IANAOC...
Tim
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praseodym
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I believe heat is needed in this case. One good example of converting a trans- to a cis-molecule is the conversion of fumaric acid (trans-butendioic
acid) to maleic acid (cis-butendioic acid). When fumaric acid is heated to 300C, it rearranges to form maleic acid. This would probably be the same
for dienes as well.
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Cloner
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The molecule I am working on should undergo a diels alder, and that is not going to happen in trans configuration. But if an equilibrium can be
created, the diels alder will happen eventually.
I know that light can do this, but wasn't sure about temperature yet.
If I take the light source, how to determine the wavelength? Is anything ok? I suppose my cis-trans isomerisation occurs at one specific wavelength.
If temperature can do the trick, then it is even simpler because the only thing needed is heat, for diels alder and for isomerisation. But 300 degrees
is a lot
edit: just made s uv-vis spectrum. There is a peak at 250 nm and a broad range from 300 to 420 nm. Nothing at all after 420 nm. The compound is
lightly yellow. I would have thought the pi-pi* absorptions to be less energetic???
[Edited on 4-4-2006 by Cloner]
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