Discrimination of Rotamers of Aryl Alcohol Homologues by Infrared−Ultraviolet Double-Resonance Spectroscopy in a Supersonic Jet

Abstract

Infrared−ultraviolet double-resonance spectroscopy has been applied to discriminate rotamers of jet-cooled aryl alcohol homologues, φ-(CH 2 ) n OH, where φ represents phenyl group and n = 1, 2, and 3 correspond to benzyl, phenethyl, and 3-phenylpropyl alcohols, respectively. Experimental results indicate that different OH stretching frequencies are associated with different rotamers and that the ability of intramolecular hydrogen bonding with the benzene π-electron decreases with an increase in alkyl chain length. In each aryl alcohol, the most prominent species in jets corresponds to the non-hydrogen-bonded rotamer having higher OH stretching frequency.