Molecules of the year – 2019: twisty tetracene.

All of the molecules in this year’s C&EN list are fascinating in their very different ways. Here I take a look at the twisty tetracene (dodecaphenyltetracene) which is indeed very very twisty.[cite]10.1002/anie.201812418[/cite]

Click on image to view 3D model

Unfortunately, the authors point that the twisty-ness does not lead to a stable helical configuration at room temperatures and so separate enantiomers cannot be isolated. But its still worth speculating what the optical rotation of such a species might be if measured. An ωB97XD/Def2-SVP/SCRF=dichloromethane calculation (DOI: 10.14469/hpc/6527) gives the following values:

[α]589 -11178°
[α]800 -2310°

Of course, mere helicity (however twisty) does not necessarily map to high optical rotation! This would be a nice molecule to 3D print and sit on a coffee table for people to admire!

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