Chirality recognition in the glycidol···propylene oxide complex: a rotational spectroscopic study.

Chirality recognition in the hydrogen-bonded glycidol···propylene oxide complex has been studied by using rotational spectroscopy and ab initio calculations. An extensive conformational search has been performed for this binary adduct at the MP2/6-311++G(d,p) level of theory and a total of 28 homo- and heterochiral conformers were identified. The eight binary conformers, built of the two dominant glycidol monomeric conformers, g-G+ and g+G-, were predicted to be the most stable ones. Jet-cooled rotational spectra of six out of the eight conformers were observed and unambiguously assigned for the first time. The experimental stability ordering has been obtained and compared with the ab initio predictions. The relative stability of the two dominant glycidol monomeric conformers is reversed in some cases when binding to propylene oxide. The contributions of monomeric energy, deformation energy, and binary intermolecular interaction energy to the relative stability of the binary conformers are discussed.