Synthesis, experimental and computational study of a non-centrosymmetric material 3-methylbenzylammonium trioxonitrate

Abstract This paper shall address the synthesis and characterization of the novel non-centrosymmetric inorganic-organic hybrid material 3-methylbenzylammonium nitrate with general chemical formula C8H12N(NO3) (3MBAN), this compound has been synthesized via slow evaporation method at room temperature and it is structurally characterized by single-crystal X-ray diffraction, crystallized to the monoclinic system with space group Cc and the following parameters 7.574(3), 29.494(10), 5.1894(15), β = 128.669(11)°, Z = 4, V = 905.1(5) A3 at 150 K and its crystal structure was determined and refined down to R = 0.057 and wR = 0.140. The monoprotonated 3-methylbenzylammonium cations are linked to the trigonal (NO3−) anions by multiple bifurcated N—H…(O,O) and weak C—H…O hydrogen bonds forming R44(12) and R32(6) motifs. The paper discusses also quantitatively the intermolecular interactions using the Hirshfeld surfaces (HS) associated with 2D fingerprint plots. The optimized molecular structure and the vibrational spectra were calculated by the density functional theory (DFT) method using the B3LYP function. Good consistency is found between the calculated results and the experimental structure; IR spectra confirmed the presence of the principal bands assigned to the internal modes of the organic cation and nitrate anion. Topological approaches such as reduced density gradient (RDG), atoms in molecules (AIM), electron localization function (ELF), endorse the occurrence of intermolecular hydrogen bonds that are responsible for the stabilization of the title compound leading to high nonlinear optical (NLO) activity. The analyses of HOMO and LUMO have been used to explain the charge transfer within the molecule. The thermal analysis of the title compound indicates its melting at 395 K follows a rapid decomposition appearing around 495 K. Finally Optical absorption reveals an important band gap energy indicating stability of the title compound.