Hydrogen bonds physical interpretations

Solvent effects on chemical equilibria and reactions have been an important issue in physical organic chemistry. Several empirical relationships have been proposed to characterize systematically the various types of properties in protic and aprotic solvents. One of the simplest models is the continuum reaction field characterized by the dielectric constant, e, of the solvent, which is still widely used. Taft and coworkers [30] presented more sophisticated solvent parameters that can take solute-solvent hydrogen bonding and polarity into account. Although this parameter has been successfully applied to rationalize experimentally observed solvent effects, it seems still far from satisfactory to interpret solvent effects on the basis of microscopic infomation of the solute-solvent interaction and solvation free energy. 

The principal factors affecting solvent-ion interactions can be classified as ion-dipole, Lewis acid-base, hydrogen-bonding, solvent structural, and steric. The solvent obviously plays a major part in these interactions. Therefore, to interpret trends in conductance data, bulk solvent properties such as viscosity and dielectric constant should be considered. Table 1 lists selected physical properties for a number of organic solvents. 

We have written The Hydrogen Bond with emphasis upon the physical and chemical facts and with three primary goals in mind. The first is to compile and summarize these experimental facts, thus furnishing a basis for prediction and interpretation of hydrogen bond behavior in substances not yet studied. The second is to present a critical discussion of the present state of the theory of this bond and its effects on physical and chemical behaviors. The third is to present a bibliography (comprehensive through 1956) which will aid workers in locating relevant studies. 

---