Spectroscopic enantiodifferentiation of chiral molecules in the gas phase

✍ Scribed by Andrea Latini; Daniela Toja; Anna Giardini-Guidoni; Antonio Palleschi; Susanna Piccirillo; Maurizio Speranza

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 286 KB
• Volume: 11
• Category: Article
• ISSN: 0899-0042
• DOI: 10.1002/(sici)1520-636x(1999)11:5/6<376::aid-chir5>3.0.co;2-3

✦ Synopsis

Enantiodiscrimination of several chiral molecules, i.e. S-(+)-(s) vs R-(-)-2-butanol (r) and S-(+)-(s) vs R-(-)-2-butylamine (r), is obtained by two-color resonance-enhanced two-photon ionization time-of-flight (2cR2PI-TOF) spectroscopy of their supersonically expanded complexes with a suitable chromophore, i.e. R-(+)-1phenyl-1-propanol (R). Analysis of the 2cR2PI-TOF excitation spectra indicates that these complexes are formed in the supersonic beam in several isomeric hydrogenbonded structures. The different batochromic shifts of the band origin regions of the molecular diastereomeric complexes relative to that of bare R provide a viable means for spectroscopically discriminating the enantiomers. A further tool for their differentiation is provided by the very reproducible differences in the mass spectral fragmentation patterns of the jet-cooled diastereomeric aggregates.