From transient to induced permanent chirality in 2-propanol upon dimerization: a rotational study.

Five different hydrogen-bonded conformers of the dimer of 2-propanol have been characterized by Fourier transform microwave spectroscopy. In all observed species, the proton donor moiety adopts a gauche conformation. While in the gauche monomer a transient chirality takes place, all dimers are classical chiral systems. The Ubbelohde effect has been observed upon OH → OD isotopic substitution and its structural effects--a 5 mÅ reduction of the O---O distance--have been quantitatively defined.