Chiral Recognition of Diols by Complexation with (R)-(+)-1-Phenyl-1-propanol: a R2PI Approach in Supersonic Beam

Wavelength and mass resolved resonance-enhanced multiphoton ionization (REMPI) excitation spectra of (R)-(+)-1-phenyl-1-propanol (PR) and its complexes with some chiral diols, i.e. 1,2-propanediols, 2,3-butanediols, and 2,4-pentanediols, have been recorded after a supersonic mol. beam expansion and interpreted in the light of mol. dynamic (MD) conformational min. searches. The spectral features of the selected complexes were found to depend on cooperative hydrogen-bond interactions between the two components, whose intensity depends upon the specific configuration of the diol moiety and the relative position of its hydroxy groups. The study further confirms resonant two-photon ionization spectroscopy, coupled with time-of-flight mass resoln. (R2PI-TOF), as an excellent tool for gathering valuable information on the interactive forces in mol. clusters and for enantio-discrimination of chiral mols. in the gas phase.