²H₃-Triphenylmethane: Propping its hidden chirality

Absolute configuration of an enantiomer is defined to be “S” or “R” according to the Cahn-Ingold-Prelog rules. The distinguishing is based on the way each enantiomer rotates the plane of polarized light. However, sometimes the optical rotation can’t be measured because of the electronic properties of a chiral molecule, and therefore the determination of the absolute configuration of such molecules is extremely challenging.

We hereby report the synthesis and spectroscopic investigation of unprecedented crypto-optically active ²H_3­­-tri-phenylmethane. The chirality in this molecule comes exclusively due asymmetric positional distribution of the three deuterium atoms (ortho, meta and para), and this slight change of the nuclei at the aryl group presents formidable challenges towards the determination of its absolute configuration.

Both the synthesis and the absolute configuration made using VCD and NMR are described for the first time. We believe that our hypothesis will open new horizons in the development of innovative materials, and will help in understanding the secrets of the mysterious hidden chirality substance.

References:

Marek et. al., Angew. Chem. Int. Ed. 2015, 54,13106–13109