Quantitative Treatment of Solvent-Induced Shifts

1 Invest gations of the factors which govern the H solvent shifts 

Several kinds of approaches have been applied to the explanation of solvent effects on shifts and conversely the variations of may be used to obtain information about intermolecular interactions. 

The differential shifts have been correlated with various solvent polarity parameters. We have already mentioned that many solvent effects have been explained on the basis of hydrogen bonding with the solvent. However, for methylamine for example, a lack of correlation with the acceptor strength of the solvent is noted (P 2) (L 44). Moreover, no simple correlation with the dielectric constant e or a function of e (e-1)/ (2e+2.5), seems to hold in amines or pyridine (P 2) 

A more general analysis concerning the variations introduced by 15 29 

It is interesting to note that the N and Si shifts are opposite in direction but linearly correlated 

---