Interactions of aromatic carboxylic acids with 8-aminoquinoline: Synthesis and the crystal structures of the proton-transfer compounds of 8-aminoquinoline with nitro-substituted benzoic acids

Abstract

Proton-transfer compounds of 8-aminoquinoline with the nitro-substituted aromatic carboxylic acids 3-nitrobenzoic acid, [(C9H9N2+)(C7 H4NO4-)] (1), 4-nitrobenzoic acid, [(C9H9N2+) (C7H5NO4)] (2), 3, 5-dinitrobenzoic acid, [(C9H9N2+)(C7 H3N2O6-)] (3), 5-nitrosalicylic acid, [(C9H9N2+) (C7H4NO5-)] (4) and 3, 5-dinitrosalicylic acid, [(C9H9N2+) (C7H3N2O7-)] (5) have been prepared and characterized by using both infrared spectroscopy and single-crystal X-ray diffraction methods [(1) (4) and (5)]. In all compounds, protonation of the quinoline nitrogen occurs together with primary hydrogen-bonding interactions involving this group and the carboxylate group of the acid, while further peripheral as..