Synthesis, characterization, and theoretical investigation of optical and nonlinear optical (NLO) properties of triazene-based push–pull chromophores

Abstract A short and efficient synthetic strategy for the synthesis of triazene-substituted push–pull dyes has been developed. The formal [2 + 2] cycloaddition-retroelectrocyclization was utilized for the preparation of the target push–pull dyes. These atom-economic, click-type chemical transformations occurred under ambient conditions and provided structurally interesting push–pull dyes in high yields. The effects of different triazene substituents on optical and non-linear optical properties were investigated by means of density functional theory (DFT), in order to support design criteria. The dipole moment, HOMO-LUMO gaps, electronegativity, global chemical hardness and softness, average polarizability, first hyperpolarizability were calculated for push–pull dyes at the CAM-B3LYP/6–31++G(d,p) level of theory. Frontier orbital depictions and electrostatic potential maps were used to establish charge-transfer characteristics of the aforementioned molecules.