Hydrogen-bond donating solvents

To study solvent effects in aqueous mixtures we have used the non-hydrogen-bond-donating solvent tetrahydrofuran. With 5CN2, the molecularity with respect to water is lowered to 3, while that for DCN2 is lowered to 2 (Fig. 13.8). Clearly there is a relationship between molecularity and driving force. It is also interesting that the molecularity, or order, with respect to water, is entirely contained in the hydrogen bonds donated by water, not alcohol, since there is no methanol present. 

A second approach to molecular lines has been developed in our laboratory [6]. It owes its success to the discovery that oligomeric imides can be made soluble in strongly hydrogen-bond donating solvent mixtures. In this synthesis, repetitive imide-forming reactions lead from monomer to trimers to the nonamer 3. It was characterized by IR and NMR (end-group analysis). 

A critical compilation of scales of solvent parameters pertaining to pnre, non-hydrogen-bond donating solvents by Abboud and Notario is available in [37]. In addition to the solvent scales described in the following (with valnes listed in Table 3.9), many other scales are dealt with in [37] and elsewhere, but those shown here appear to be the most popnlarly nsed ones. 

Figure 2. (A) Absorption shift of dye solution as a function of dielectric constant in non-hydrogen-bond donating solvents, (B) Absorption shift of dye solution as a function of dielectric constant in hydrogen bonding solvents.

The parameters are DI (the Dispersion-Induction Parameter), ES (Electrostatic, Non-Hydrogen Bond Donating Solvents), ui (Lewis Acidity) and Pi (Hydrogen-Bond Basicity), while di, e, a, and h are the regression coefftcients. 

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