Synthesis, crystal growth and supramolecular chemistry of 4-dimethylaminopyridinium salts of benzoates and a phenolate ion

Abstract

Abstract Seven novel molecular salts were synthesized from the commonly available 4-dimethylaminopyridine organic base and benzoic acid derivatives contain additional functional groups. Benzoic acids with additional hydroxyl, nitro, amino, and bromo functional groups, were successfully employed and investigated their role in non-covalent interactions within the supramolecular chemistry of heterosynthons solid-state architecture. The collection of all 4-dimethylamopyrinium salts of benzoates and phenolate was accomplished through the utilization of conventional solvent evaporation technique. The resulting molecular salts were afforded by deprotonation of the acidic moiety such as COOH, or OH to the ring N of 4-dimethylaminopyridine, establishing a strong charged-assisted hydrogen bond between the deprotonated group (benzoate or phenolate) and protonated ring N. The structure of compounds was fully elucidated by single X-ray diffraction, powder X-ray diffraction, 1H NMR, FT-IR, and thermogravimetric analysis. The crystal packing is interpreted by the strong charge-assisted N–H⋯O hydrogen bond between the NH+ and the corresponding deprotonated group and O–H⋯O, N–H⋯N hydrogen bonding. The analysis concluded that C–H⋯O, CH3⋯O, C–H⋯π, CH3⋯π, π–π, C–H⋯Br, and CH3⋯Br contacts contribute significantly to stabilizing and expanding the high-dimensionality (2D–3D framework) of the structures. The structures were thoroughly explored for their various bonding and nonbonding interactions, as well as their supramolecular chemistry in detail. The antimicrobial activities of all compounds were evaluated using the Oxford cup method.