R2PI Study of intermolecular hydrogen bond in solvent-free chiral complexes.

Abstract

One- and two-color, mass selected R2PI spectra of the S(1)<--S(0) transitions in the bare (+)-(R)-1-phenyl-1-ethanol (E(R)) and its complexes with different solvent molecules (solv) (-)-(R)-2-butanol (B(R)) or (+)-(S)-2-butanol (B(S)) and (-)-(R)-2-butylamine (A(R)) or (+)-(S)-2-butylamine (A(S)), have been recorded after a supersonic molecular beam expansion. The one-color R2PI excitation spectra of the diastereomeric complexes are characterized by significant shifts of their band origin relative to that of bare E(R). The extent and the direction of these spectral shifts are found to depend on the structure and the configuration of solv and are attributed to different short-range interactions in the ground and excited states of the complexes. In analogy with other diastereomeric complexes, the phenomenological binding energy of the homochiral cluster is found to be greater than that of the heterochiral one.