Modelling neurotransmitter functions: a laser spectroscopic study of (1S,2S)-N-methylpseudoephedrine and its complexes with achiral and chiral molecules

Wavelength and mass resolved resonance-enhanced two photon ionization (R2PI) excitation spectra of (1S,2S)-N-Me pseudoephedrine (MPE) and its complexes with several achiral and chiral solvent mols., including water (W), Me (R)-lactate (LR), Me (S)-lactate (LS), (R)-2-butanol (BR), and (S)-2-butanol (BS), have been recorded after a supersonic mol. beam expansion and examd. in the light of ab initio calcns. The spectral patterns of the selected complexes have been interpreted in terms of the specific hydrogen-bond interactions operating in the diastereomeric complexes, whose nature in turn depends on the structure and the configuration of the solvent mol. The obtained results confirm the view that a representative neurotransmitter mol., like MPE, "communicates" with the enantiomers of a chiral substrate through different, specific interactions. These findings can be regarded as a further contribution to modeling neurotransmitter functions in biol. systems.