Supramolecular Assembly of Morpholin-4-ium hydroxy(diphenyl)acetate—Structural, Spectral and Nonlinear Optical Analyses

Abstract

A supramolecular assembly of Morpholin-4-ium hydroxy(diphenyl)acetate (MHA) was synthesized by acquiring morpholine and benzilic acid in equimolar ratio via solvent vaporization technique using methanol as a solvent. The structure of MHA was analyzed by single-crystal X-ray diffraction analysis, which confirms that the crystal is crystallized in a monoclinic crystal system with C2/c centrosymmetric space group. The molecule was stabilized via NH….O and OH..O supramolecular assembly networks. Close contacts are observed over dnorm surface with red spots, from Hirshfeld analysis which are owing to OH…O and NH…O intermolecular interactions. 1H NMR analysis confirmed the migration of proton from benzilic acid to morpholine and in 13C NMR analysis, the signal at δ 176.36 ppm confirmed the presence of highly deshielded carboxylate carbon in the molecule. The vibrational frequencies associated with the functional groups in the MHA crystal are estimated using Fourier transform infrared spectroscopy. Refractive index (n) and extinction coefficient (K), bandgap, optical conductivity (σop), electrical conductivity (σel), optical susceptibility (χop) and polarization (P) were estimated using UV–vis spectroscopy. Fluorescence peaks were observed at 334 and 380 nm via photoluminescence spectroscopy. The third order nonlinear optical properties were obtained using Z-scan studies. The Z-scan curve in the closed aperture configuration indicates the change in refractive index of the MHA crystal with a strong self-defocusing effect.