Potentiometric investigations and effects of substituents on basicity of some acyclic(polyether)s with Schiff base type in acetonitrile and acetic acid

The basicity of the acyclic(polyether)s with Schiff base type, namely 1,5-di[N-2-oxyphenyl-salicylidene]-3-oxapentane (1), 1,5-di[N-2-oxyphenyl-5-methoxvsalicylidene]-3-oxapentane (2), 1,5-di[N-2-oxyphenyl-5-broinosalicylidene]3-oxapentane (3), 1,5-di[N-2-oxyphenyl-5-nitrosalicylidene]-3-oxapentane (4), 1,5-di[N-2-oxyphenyl-2-oxo-1-naphthylidenemethylamino]-3-oxapentane (5), 1,8-di[N-2-oxyphenylsalicylidene]-3,6-dioxaoctane (6), 1,8-di[N-2-oxyphenyl-5-methoxysalicylidene]-3,6-dioxaoctane (7), 1,8-di[N-2-oxyphenyl-5-bromosalicylidene]-3,6-dioxaoctane (8), 1,8-di[N-2oxy phenyl-5-nitrosalicylidene]-3,6-dioxaoctane (9), 1,8-di[N-2-oxyphenyl-2-oxa-1-naphthylidenemethylamino]-3,6-dioxaoctane (10) was investigated potentiometrically in acetonitrile and acetic acid solvents. All compounds except one have shown rather well-shaped and stoichiometric titration curves in acetonitrile and acetic acid. The effect of substituents on basicities of these compound have been investigated. The orders of the basicity of substituents is H > OCH3 > Br > NO2.