Exploring the NLO Properties of Brominated Dimethoxybenzaldehydes: From Synthesis to Molecular Modeling.

The development of multifunctional organic compounds with advanced optical properties is crucial for technological advancements in photonic devices. In this study, we synthesize and characterize three brominated dimethoxybenzaldehyde derivatives: 4,5-dibromo-2,3-dimethoxybenzaldehyde (IB1), 2,3-dibromo-5,6-dimethoxybenzaldehyde (IB2), and 4,6-dibromo-2,3-dimethoxybenzaldehyde (IB3). Single-crystal X-ray diffraction reveals that the positional variation of bromine atoms significantly influences molecular geometry and electronic configurations. The DFT calculations at the CAM-B3LYP/aug-cc-pVTZ level provide insights into their electronic properties and third-order nonlinear optical (NLO) susceptibilities (χ). By employing a Supermolecule (SM) approach to model the crystalline environment, we account for electrostatic interactions with adjacent molecules, enhancing the accuracy of our simulations. IB2 and IB3 exhibit significant NLO responses, with χ values reaching up to 172.65 × 10 (m/V) at 532 nm, underscoring their potential for integration into advanced photonic devices. Our findings elucidate the structure-property relationships in IB1, IB2, and IB3, highlighting their applicability in photonic technologies.