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.[1]

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!

References

  1. Y. Xiao, J.T. Mague, R.H. Schmehl, F.M. Haque, and R.A. Pascal, "Dodecaphenyltetracene", Angewandte Chemie International Edition, vol. 58, pp. 2831-2833, 2019. http://dx.doi.org/10.1002/anie.201812418

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