Selectivity in proton transfer, hydrogen bonding, and solvation

The site of protonation (or deprotonation) of polyfunctional bases and acid s can be determined through the comparison of experimental NMR properties ( chemical shift and relaxation rates) with the corresponding data calculated by quantum chemical methods. The results can be interpreted in terms of th e competition between intrinsic base strengths and solvation. Qualitatively similar criteria are found to hold for hydrogen bonding. The selective enr ichment in a cosolvent in the solvation shell of a solute dissolved in a so lvent mixture (preferential solvation) can be determined through the analys is of intermolecular cross-peak intensities in NOESY spectra.