A Symmetric Recognition Motif between Vicinal Diols: The Fourfold Grip in Ethylene Glycol Dimer.

Ethylene glycol has a transiently chiral, asymmetric global minimum structure, but it favors a highly symmetric, achiral dimer arrangement which has not been considered or found in previous quantum-chemical studies. Complementary FTIR and Raman spectroscopy in supersonic jets allows for the detection and straightforward assignment of this four-fold hydrogen-bonded dimer, which introduces an interesting supramolecular binding motif for vicinal diols and provides a strong case for transient chirality synchronization.