Bond donor and acceptor strength

The most informative approach to understanding these solvation forces at the present time is the Solvatochromic method introduced by Kamlet and his colleagues, which separates the contributions to log/ into measures of solute size, polarity/polarizability, and hydrogen bond donor and acceptor strength. In its most general form, log/ for any solvent pair can be stated as... 

HYBOT will compute hydrogen bond donor (SCa) and acceptor (2Ca) factors that describe the donor and acceptor strengths, respectively, of a compound. Using these two parameters, the authors developed models with significant statistical quality (r2 = 0.91, q2 = 0.87) of intestinal absorption. 

The basic features of the model are the following a) Lone pair and bonds are classified according to their intrinsic donor and acceptor abilities. Tables 36 and 37 summarize the relative intrinsic donor and acceptor strengths of various lone pairs and bonds. 

The E and C parameters are consistent with chemical intuition and with the earlier qualitative explanations of donor and acceptor strengths in terms of the ionic-covalent bonding and in some cases with... 

Wuest et al. have also prepared a related tetrahedral tecton 8.63, which also produces a diamondoid polymeric framework. In this case, the solid-state network is seven-fold interpenetrated, with one diamondoid lattice filling much of the large cavities in those adjacent. It is possible that the interpenetration in this instance is a result of the self-complementary nature of the host, which contains an equal number of hydrogen bond donor and acceptor sites. However, even in this case small cavities exist, which are filled by two molecules of butyric acid per host formula unit. The formation of these kinds of framework materials opens entirely new possibilities for tailor-made porous materials with very large cavities, although it is unlikely that purely organic frameworks will ever rival aluminosilicate-based materials for sheer mechanical strength. 

TABLE 21.3 Potential Hydrogen Bond Donor and Acceptor Groups Classified According to Their Strength of Interaction ... 

Tab. 6.1 Potential hydrogen bond donor and acceptor groups classified according to their strength of interaction.

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