Chiral clusters in a supersonic beam: R2PI-TOF spectroscopy of diastereomeric carboxylic esters/(R)-(+)-1-phenyl-1-propanol complexes

Abstract

Wavelength and mass resolved resonance-enhanced two photon ionization (R2PI) excitation spectra of (R)-(+)-1-phenyl-1-propanol (P_R) and its complexes with some chiral esters, i.e. methyl lactates (L_R and L_S), methyl 3-hydroxybutyrates (H_R and H_S), and methyl 2-chloropropionates (C_R and C_S), have been recorded after a supersonic molecular beam expansion and interpreted in the light of DFT calculations. The spectral features of the selected complexes were found to depend on the nature of hydrogen-bond interactions within the diasteromeric complexes, whose intensity in turn depends upon the structure and the configuration of the estereal moiety. The study further confirms resonant two-photon ionization spectroscopy, coupled with time-of-flight mass resolution (R2PI-TOF), as an excellent tool for gathering valuable information on the interactive forces in molecular clusters and for the enantiodiscrimination of chiral molecules in the gas phase.