Molecular Recognition of Chiral Conformers: A Rotational Study of the Dimers of Glycidol

摘要

The role of chirality in favoring the formation and stability of specific aggregates can be investigated through the behavior of relatively simple molecular systems in forming molecular complexes, with the subunits held together through nonbonding interactions. The conformational and dynamical properties of such weakly bound complexes can then guide our understanding of molecular recognition, which characterizes many biological processes.rnVarious spectroscopic techniques, with different degrees of sensitivity and spectral resolving power, are already established for this purpose. A wealth of results obtained by resonant-two-photon-ionization (R2PI) excitation spectra of the S_1 ← S_0 transition of mass resolved hydrogen bonded molecular complexes have been reported. To observe the electronic transitions of chiral systems, typically their fluorescence spectrum, this technique requires a chromophoric group. Therefore, chiral alcohols with an aromatic ring, such as indan-1-ol, 1-phenyl-1-propanol, 2-naphtyl-1-ethanol, etc., have been investigated. Also gas phase supersonic-jet Fourier transform infrared (FTIR) spectroscopy of the OH-stretching bands was used for this purpose, and clusters of neutral methyl lactate, glycidol, and related aggregates beyond dimers were observed. Both techniques required complementary theoretical calculations to assign the experimental bands to specific conformers.