Determination of the Minimum Energy Conformations of Benzyl Alcohol and 2-Phenethyl Alcohol.

摘要

Supersonic jet mass resolved excitation spectroscopy is employed to determine the minimum energy conformation of the alcohol group with respect to the benzene ring for benzyl alcohol (BA) and 2-phenethyl alcohol (2-PEA). The mass resolved excitation spectra of these molecules are presented and assigned. The C-O bond orientation in BA is determined to be perpendicular to the benzene ring (tau (Cortho-Cipso-C alpha-O) = 90deg) and in 2-PEA it is determined to be gauche with respect to the Cipso-C alpha bond (tau(Cipso-C alpha-C beta-O)= + or -60 deg). By considering the OH....pi-electron cloud internal hydrogen bonding and the repulsive interaction between the non-bonding electrons on the oxygen atom and pi-electron cloud, the hydroxyl proton in both molecules is suggested to be pointing toward the benzene ring. (RRH)