Phenol-base complexation enthalpies

According to the t-scores, Vmin is the most important parameter also for this correlation. However, the relative importance of Is,min is much larger than in the correlation with the phenol-base complexation enthalpies, consistent with the larger effect of charge transfer on frequency shifts compared to enthalpies. 

Computed quantities are from ref. (50). Experimentally determined enthalpies for 1.1 phenol-base complexation in apolar solvents (51). Values in brackets are predicted from eq. 10. Experimentally determined OH frequency shifts for methanol-base complexes in carbon tetrachloride. These values were obtained by Berthelot and co-workers (52-54). Values in brackets are predicted from eq. 11. Experimentally determined gas phase proton affinities (55). Values in parentheses were not included in the correlation with computed quantities. Values in brackets are predicted from eq. 12. ... 

Drago and coworkers have also calculated the enthalpy values for the formation of many complexes or hydrogen bonds by NMR and calorimetric techniques. For example, in a series of phenols or t-BuOH, they observed the IR frequency shifts (Avqh) of the hydroxyl compounds and found that a linear relationship exists between bases and individual acids. In Table 7 shows some AH values calculated by equation 2, and Avqh values of t-BuOH" " while in Table 8 frequency data Avq of various substituted phenols and the AH values are given. 

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