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Hydrogen‐bonding 8. Possible equivalence of solute and solvent scales of hydrogen‐bond basicity of non‐associated compounds
Author(s) -
Abraham Michael H.,
Buist Gabriel J.,
Grellier Priscilla L.,
McGill R. Andrew,
Prior David V.,
Oliver Susan,
Turner Elizabeth,
Morris Jeffrey J.,
Taylor Peter J.,
Nicolet Pierre,
Maria PierreCharles,
Gal JeanFrançois,
Abboud JoséLuis M.,
Doherty Ruth M.,
Kamlet Mortimer J.,
Shuely Wendel J.,
Taft Robert W.
Publication year - 1989
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.610020706
Subject(s) - chemistry , solvatochromism , hydrogen bond , solvent , aniline , solvation , computational chemistry , molecule , organic chemistry
Using the solvatochromic indicator method, a scale of solvent hydrogen‐bond basicity, β 1 (General), has been set up using a series of double regression equations,\documentclass{article}\pagestyle{empty}\begin{document}$$ \nu = \nu _0 + s\pi _1^* + b\beta _1 $$\end{document}for 11 aniline‐type indicators. A similar solvent scale, β 1 (Special), has been constructed by the homomorphic comparison method using only results by Laurence et al. on the indicators 4‐nitroaniline and 4‐nitro‐ N , N ‐dimethylaniline. Results are available from our previous work on a general solute scale, β 2 H , and we have also obtained a special solute scale, β 2 (p K HB ) from available log K values for hydrogen‐bond complexation of bases with 4‐fluorophenol in CCl 4 . However, the two solute β 2 scales are virtually identical. It is shown that there is a general connection between β 1 (General) and β 2 H , with r = 0·9775 and s.d. = 0·05 for 32 compounds, and between β 1 (Special) and β 2 H , with r = 0·9776 and s.d. = 0·06 for the same 32 compounds. The latter correlation over 60 compounds yields r = 0·9684 and s.d. = 0·07. However, there are so many compounds in these regressions for which the differences in the solvent and solute β values are larger than the total expected error of 0·07 units that the use of β 1 to predict β 2 or vice versa is a very hazardous procedure. About 70 new β 1 values obtained by the double regression method are also reported.