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

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 hyper-polarizability 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. (C) 2020 Elsevier B.V. All rights reserved.