Synthesis, characterization, and computational exploration of 6-ethoxy-2-aminobenzothiazolium diphenylacetate crystal as an efficient NLO material

In this paper, nonlinear optical (NLO) active single-crystal 2-amino-6-ethoxy benzothiazolium diphenylacetate ( BTDPA ) crystallized in an orthorhombic crystal system with non-centrosymmetric space group P2 1 2 1 2 1 . The thermal studies (TG–DTA and DSC) and characterization studies such as FT-IR, FT-Raman, NMR, UV–Vis–NIR, PXRD, and NLO studies (Kurtz–Perry powder method) of BTDPA crystal were recorded and investigated. Molecular geometry of BTDPA was optimized using quantum chemical computational method with M06-2X functional and 6-31G** basis set. Frontier molecular orbitals, molecular electrostatic potential, and density of states were calculated for optimized geometry to see the trend of electronic charge distributions at ground state. The TD-M06-2X method was used to calculate electronic transitions which were compared with experimental UV–Visible spectrum of BTDPA. Additionally, at molecular-level static isotropic, anisotropic linear polarizability, and third-order NLO polarizability were also calculated which were found to be 42.33 × 10 –24 esu, 24.27 × 10 –24 esu, and 18.95 × 10 –36 esu, respectively. The current investigation of BTDPA molecule highlights good optical and nonlinear optical properties which can be of added value in the field of optoelectronic and laser applications.