New benzotriazole-based D–A–D type solvatochromic dyes for water content detection in organic solvents

Two new D-A-D structured organic dyes ( LM1 and LM2 ) based on methoxy substituted triphenylamine (MeO-TPA) as the electron donor , N -aryl benzotriazole as the electron acceptor have been designed and synthesized for water content detection in organic solvents . Both dyes exhibit large stoke shift with solvatochromic properties and display apparent fluorescence quenching upon the addition of different amount of water in organic solvents. Compared to LM1 , LM2 with stronger electron-withdrawing acceptor fluorinated benzotriazole possesses red-shifted absorption and fluorescence emission , enhanced intramolecular charge transfer (ICT) properties and stronger hydrogen-bonding interaction, resulting in a lower limit of detection (LOD) for water. The LODs in THF and 1,4-dioxane of LM2 are 0.009 % and 0.024 %, respectively, which indicates its great potential application in detecting water content in organic solvents. • Two D-A-D structured solvatochromic dyes were designed and synthesized. • The two dyes exhibited significant fluorescence quenching with the addition of water in organic solvents. • LM2 with F atom in benzotriazole is more suitable for water sensing application.