The structure-property studies and mechanism of optical limiting action of methyl 4-((4-aminophenyl)ethynyl)benzoate crystal under continuous wave laser excitation

This study focuses on the design of the new dye of donor-π-acceptor (D−π−A) system of methyl 4-((4-aminophenyl)ethynyl)benzoate (MAPEB) to highlight its structural-property relation through a combined experimental and quantum chemical calculation approaches for optical limiting applications. MAPEB was synthesized via aerobic condition palladium-catalysed Sonogashira cross-coupling reaction with good yield. This molecular structure was confirmed by single crystal X-ray crystallographic analysis and the crystal exhibits monoclinic non-centrosymmetric space group of Pc. The existence of intermolecular interactions was confirmed by Hirshfeld analysis, showing high contribution of C⋯H contact which suggested the high nonlinear optical response of the compound. The experimental spectroscopic data including Fourier Transform Infrared (FT-IR), 1H and 13C Nuclear Magnetic Resonance, electronic absorption spectra, HOMO-LUMO energy gap were compared with Density Functional Theory (DFT) at 6–311++G (d,p) basis set. The experimental results complement the theoretical findings in supporting anticipated electronic properties of the molecule. Additionally, the z-scan analysis unveils an excellent value of χ3 of MAPEB in the order of 10−6 esu which indicate good nonlinear optical material under 532 nm continuous wave laser. Low optical limiting action was measured at 110 kW/cm2 which is suitable for various continuous wave laser applications. These findings prove that MAPEB has the potential to be employed as NLO materials for photonic applications. [Display omitted] •The newly synthesized D-π-A molecular structure (MAPEB) containing amino and methoxycarbonyl moieties on the phenylethynylphenyl backbone is a promising NLO material.•The head-to-tail arrangement of intermolecular N–H⋯O and C–H···π interactions in MAPEB strengthen the molecular architecture and induce high SHG efficiency.•The MAPEB small energy gap leads to efficient charge excitation, while the large amplitude of electronic dipole moment influences strong nonlinearity properties.•MAPEB possesses an excellent value of third-order susceptibility (10−6 esu) and exhibit low optical limiting threshold which suitable for various CW laser operation.