The electric dipole moments of aniline, aminopyridines, and their N-methyl derivatives in benzene and 1,4-dioxan solutions

Abstract

The electric dipole moments of aniline, 2-, 3-, and 4-aminopyridines, of their mono- and di-N-methyl derivatives, and of 2,3- and 2,6-diaminopyridines have been calculated from measurements of the dielectric constants, specific volumes, and refractive indices of their solutions in benzene and 1,4-dioxan at 25·00°. The results for 3-amino-pyridine are analogous to those for aniline. There is an appreciable mesomeric interation, increasing on N-methylation, between an amino-group in the 4 position and the pyridine ring but in the 2 position its direct interaction with the heterocyclic nitrogen atom complicates the situation. Amino-hydrogen atoms form bonds to dioxan solvent molecules.