Analysis of hydrogen-bond complexation constants in 1,1,-trichloroethane:: the α2Hβ2H relationship

Hydrogen-bond complexation constants determined by Taylor and co-workers using 1,1,1-trichloroethane (TCE) solvent have been analysed through the alpha(2)(H) beta(2)(H) relationship; alpha(2)(H) and beta(2)(H) are the solute hydrogen-bond acidity and basicity parameters obtained from complexation constants in tetrachloromethane, Constants for three alcohol/N-methylpyrrolidinone complexations have been determined in TCE, and if these are used instead of the original alcohol/N-methylpyrrolidinone complexation constants, a good relationship is obtained, eqn. (i), The slope in eqn. (i) is smaller than that for the alpha(2)(H) beta(2)(H) relationship in tetrachloromethane, but the intercept is the same. log K = 6.856 alpha(2)(H) beta(2)(H) - 1.144 (i) n = 84, r(2) = 0.9604, sd = 0.16, F = 1993 Eqn. (i) has been used to obtain 25 new alpha(2)(H) values for acids; these include acetanilides, sulfonamides, triazoles and tetrazoles, The latter two types of compound have very large alpha(2)(H) values; that for 5-phenyl-1,2,3,4-tetrazole (0.88) being near the value for dichloroacetic acid (0.90), Values of beta(2)(H) for 31 hydrogen-bond bases have also been calculated using eqn, (i), These include bases with heterocyclic moieties to which beta(2)(H) values had not previously been assigned, e.g. oxazole, isoxazole, triazoles and a tetrazole.