Synthesis, characterization, and a study of the influence of [HSO4]- and [SO4]2- on thermal phase transition and thermal stability of two new organic acid salts containing dication cyclic amine

Two new organic acid salts were synthesized, and their chemical structures were elucidated by various spectroscopy analyses including infra-red, one and two dimensions of nuclear magnetic resonance, and mass spectroscopy. The pH and thermal behavior and thermal stability displayed different acidity and stability which approved the existence of different chemical structures for two acid salts containing the same dication i.e., 4,4'-trimethylene-N,N'-dipiperidinium and two different anions of sulfate and hydrogensulfate. Although H-1 NMR did not show acid proton of [HSO4](-), the FTIR spectra of acid salts act as key support to approve of their chemical structures. The thermal behavior and thermal stability of two as-synthesized acid salts were mainly different. This fact indicates various electrostatic and hydrogen-bonding interactions, which in turn, is further supports their proposed chemical structures. (C) 2021 Elsevier B.V. All rights reserved.