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Short‐Range Interactions within Molecular Complexes Formed in Supersonic Beams: Structural Effects and Chiral Discrimination
Author(s) -
Latini Andrea,
Satta Mauro,
Giardini Guidoni Anna,
Piccirillo Susanna,
Speranza Maurizio
Publication year - 2000
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/(sici)1521-3765(20000317)6:6<1042::aid-chem1042>3.0.co;2-w
Subject(s) - chemistry , steric effects , chromophore , molecule , excited state , conformational isomerism , spectral line , enantiomer , crystallography , computational chemistry , photochemistry , stereochemistry , atomic physics , organic chemistry , physics , astronomy
One‐ and two‐color, mass‐selected R2PI spectra of the S 1 ←S 0 transitions in the bare chiral chromophore R ‐(+)‐1‐phenyl‐1‐propanol ( R ) and its complexes with a variety of alcoholic solvent molecules ( solv ), namely methanol, ethanol, 1‐propanol, 2‐propanol, 1‐butanol, S ‐(+)‐2‐butanol, R ‐(−)‐2‐butanol, 1‐pentanol, S ‐(+)‐2‐pentanol, R ‐(−)‐2‐pentanol, and 3‐pentanol, were recorded after a supersonic molecular beam expansion. Spectral analysis, coupled with theoretical calculations, indicate that several hydrogen‐bonded [ R⋅solv ] conformers are present in the beam. The R2PI excitation spectra of [ R⋅solv ] are characterized by significant shifts of their band origin relative to that of bare R . The extent and direction of these spectral shifts depend on the structure and configuration of solv and are attributed to different short‐range interactions in the ground and excited [ R⋅solv ] complexes. Measurement of the binding energies of [ R⋅solv ] in their neutral and ionic states points to a subtle balance between attractive (electrostatic and dispersive) and repulsive (steric) forces, which control the spectral features of the complexes and allow enantiomeric discrimination of chiral solv molecules.