Molecular and suprramolecular chirality: R2PI spectroscopy as a tool for the gas-phase recognition of chiral systems of biological interest

A review. In life sciences, diastereomeric chiral mol./chiral receptor complexes are held together by a different combination of intermol. forces and are therefore endowed with different stability and reactivity. Detn. of these forces, which are normally affected in the condensed phase by solvent and supramol. interactions, can be accomplished through the generation of diastereomeric complexes in the isolated state and their spectroscopic investigation. This review presents a detailed discussion of the mass resolved Resonant Two Photon Ionization (R2PI-TOF) technique in supersonic beams and introduces an overview of various other technologies currently available for the spectroscopic study of gas phase chiral mols. and supramol. systems. It reports case studies primarily from the authors' recent work using R2PI-TOF methodol. for chiral recognition in clusters contg. mols. of biol. interest. The measurement of absorption spectra, ionization and fragmentation thresholds of diastereomeric clusters by this technique allow the detn. of the nature of the intrinsic interactions, which control their formation and which affect their stability and reactivity.