Solvent effects on the electronic structure, excited states, and nonlinear optical properties of two anthracene-based chalcone derivatives: a DFT and TD-DFT study

Context Anthracene-based chalcones are π-conjugated donor–acceptor chromophores with potential second-order nonlinear optical applications, but solvent-field polarization and solvent-induced geometry relaxation can affect their response in different ways. This work compares ANT–IND and ANT–DMNAF, which differ in donor environment, to identify how the medium controls absorption and static first hyperpolarizability. Solvation red-shifts the principal UV band by about 14 nm and substantially increases the computed nonlinear optical response. Methanol-optimized ANT–DMNAF reaches β∥=10269 a.u. (88.7× 10⁻³⁰ esu) β ‖ = 10269 a . u . ( 88.7 × 10 - 30 e s u ) , exceeding ANT–IND under the same conditions and indicating a solvent-dependent crossover in the computed NLO ranking. Methods Gas-phase and solvated geometries were optimized with density functional theory at the CAM-B3LYP/6–31 + G(d,p) level using the SMD continuum model in Gaussian 16. Harmonic frequency calculations confirmed true minima. The six media considered comprise the gas phase plus five solvents: n-hexane, toluene, dichloromethane, methanol, and DMSO. Time-dependent DFT calculations with 30 excited states provided UV–Vis spectra, and static dipole moments, isotropic polarizabilities, and first hyperpolarizabilities were obtained analytically. NLO properties were evaluated with both fixed gas-phase geometries (GasGeom) and solvent-relaxed geometries (SolvGeom); this comparison is used as a computational sensitivity analysis and not as an experimentally separable partition of the response.