Synthesis of a Tight Intramolecular OH···Olefin Interaction, Probed by IR, 1H NMR, and Quantum Chemistry

We have synthesized a molecule containing a tight hydrogen-bonding interaction between an alcohol and a nonconjugated π-system. The strength of this hydrogen bond results in a large red shift, nearly 189 cm–1, on the alcohol stretching frequency in the IR spectrum in comparison to a free alcohol control. The interaction is notable in that it possesses a better defined intramolecular hydrogen bond compared to the usual molecules for which it is noted, such as syn-7-norbornenol. This interaction was studied through the use of IR and NMR spectroscopy, X-ray crystallography, and molecular modeling calculations.