Impact of intermolecular charge transfer interactions on structural, spectral and third-order nonlinear optical properties of a semiorganic crystal: Poly (bis 4-methoxybenzylammonium) tetra-μ-chlorido-cadmate (II)

The correct crystal system and space group of the title crystal are reported. Powder X-ray diffraction (PXRD) study validates the crystal structure of poly (bis 4-methoxybenzylammonium) tetra-μ-chlorido-cadmate (II) (4MBACD) crystal. The crystal exhibits the optical transmittance from 270 to 1100 nm. The vibrations of different functional groups, formation of crystal, coordination of metal and the intermolecular hydrogen bonding impact in the crystal were analyzed by FT-Raman and 1H nuclear magnetic resonance (NMR) spectroscopy. The 1H NMR spectrum of 4MBACD crystal is recorded in DMSO and D2O solvent but the protonation of amino moiety is revealed only in DMSO solvent. The mechanical stability was determined by Vicker's microhardness study. The Z-scan analysis was carried out to know the nonlinear refractive index (n2), the nonlinear absorption coefficient (β) and third-order nonlinear susceptibility (χ(3)). The result reveals that the crystal possesses saturable absorption and self-defocusing properties. 4MBACD crystal exhibits higher third order nonlinear susceptibility χ(3) = 6.21 × 10−6 esu compared to some well-known crystals due to the impact of intermolecular charge transfer interactions. This ensures the suitability of 4MBACD crystal for nonlinear optical (NLO) applications.