STERIC FACTORS IN THE SHORT-RANGE SOLVATION OF SECONDARY AMINES

Article abstract of DOI:10.1016/0022-2860(90)80147-C

Steric aspects of the short-range solvation of proton transfer complexes between 2,4-dinitrophenol and various secondary amines was studied in benzene-DMSO and benzene-dioxane mixed solvent systems.Diisopropylamine was hindered when compared with diethylamine, and 2,2,6,6-tetramethylpiperidine was hindered when compared with 2,6-dimethylpiperidine in forming the proton transfer complex.The smaller electron-donating solvent dimethylsulfoxide was capable of solvating the more hindered amines, but the the bulkier dioxane could only solvate diethylamine and dimethylpiperidine readily.Tetrahydropyran could solvate tetramethylpiperidine weakly, inferring that it did not solvate in precisely the same fashion as does dioxane.It is concluded that the solvation structure is sufficiently crowded as to be sensitive to small changes in the structures of the participants.