Synthesis and characterization of p-xylylenediaminium bis(nitrate). Effects of the coordination modes of nitrate groups on their structural and vibrational properties

The p-xylylenediaminium bis(nitrate) compound have been synthesized and then, it was characterized by using Fourier Transform infrared (FT-IR) in the solid phase and, by using the Ultraviolet-Visible (UV-Visible) and Hydrogen and Carbon Nuclear Magnetic Resonance (H-1- and C-13-NMR) spectra in aqueous solution and in dimethylsulfoxide solvent. In this work, two monodentate and bidentate coordination modes were considered for the nitrate ligands in both media in order to study the structural and vibrational properties of that salt. Hence, the natural bond orbital (NBO), atoms in molecules (AIM), Merz-Kollman (MK) charges, molecular electrostatic potentials (MEP) and frontier orbitals studies were performed for p-xylylenediaminium bis(nitrate) and their cation and anion species taking into account for the salt those two coordination modes for the nitrate ligands. The intermolecular interactions of this salt were also evaluated by Hirshfeld surface analysis. The B3LYP calculations performed by using the hybrid method and the 6-311G* and 6-311++G basis sets generate monodentate and bidentate structures with C-i and C-2 symmetries, respectively. The force fields and the force constants values for these two structures were also computed and their complete vibrational assignments were performed by using those both levels of theory. The strong band at 1536 cm(-1), the bands between 2754 and 2547 cm(-1) and the bands between 1779 and 1704 cm(-1) support clearly the presence of the dimeric species while the IR bands at 1986/1856 cm(-1) could justify the presence of the bidentate species in the solid phase. (C) 2017 Elsevier B.V. All rights reserved.