Preparation, Crystal Structure, Physico‐chemical and Nonlinear Optical Properties of a New D‐π‐A Centrosymmetric Stilbazolium Framework of 4‐[2‐(3hydroxy‐phenyl)‐vinyl]‐1‐methyl‐pyridinium iodide (HMPI)

Abstract

New organic Stilbazolium cation Salt of 4‐[2‐(3 hydroxy‐phenyl)‐vinyl]‐1‐methyl‐pyridinium iodide (HMPI), which was obtained through solvent evaporation solution growth. The crystal structure was proved via the SC‐XRD technique. Its outcome reveals that the HMPI crystallised in a centrosymmetric pattern (P121/n1) and monoclinic crystal system. The compositional analysis was performed via 1H NMR and 13C NMR. The FT‐IR spectrum was used to determine the vibrational mode of the different molecular groups present in the material. The intermolecular interactions in the crystal structure were studied using Hirshfeld surface analysis. The molecular orbital energies (HOMO‐LUMO) and molecular electrostatic potential (MESP) were estimated using the Gaussian program with the density functional theory (DFT) method. The linear optical study revealed the transmittance percentage, lower cut‐off wavelength, and energy band gap for HMPI crystal. In the photoluminescence study, a green colour broad emission peak is observed at 521 nm. TG and DTA measured the thermal behaviour of grown HMPI crystal. Chemical etching and atomic force microscopy (AFM) experiments were used to report the surface properties of grown HMPI crystal. The Z‐scan technique, a He−Ne continuous wave laser at 632.8 nm used to measure the third‐order nonlinear optical susceptibility of the HMPI crystal. The Z scan approach reveals a saturable absorption and self‐defocusing nature of the title crystal.