Synthesis, physicochemical, nonlinear optical properties of azonaphtharylmide dyes: Dyeing and UV-protection performance on wool, silk, polyester

Abstract

This study focuses on the synthesis and characterization of three azonaphtharylmide dyes, APAS, APASD, and APASTR, using naphthol AS, ASD, and ASTR couplers. The research also observes the presence of a hydrazone tautomer in a DMSO solution. It was characterized through spectroscopic analysis, which revealed three characteristic carbonyl carbon peaks in the 13C NMR spectrum. The calculated low LUMOs (−3.46 eV to −3.54 eV) align closely with experimental calculations (−3.45 eV to −3.48 eV), indicating the potential of these dyes as electron acceptors. Furthermore, the alignment of frontier molecular orbital (FMO) values supports their suitability for electron acceptance. When applied to wool, silk, and polyester materials, these dyes confer UV protection properties, with wool-dyed fabrics achieving a UV Protection Factor (UPF) of 50+. Additionally, these dyes exhibit significantly improved nonlinear optical responses, with beta (β0) values ranging from 11 × 10−30 to 23 × 10−30 esu and gamma (γ0) values ranging from 275 × 10−36 to 365 × 10−36 esu, indicating their functionality as nonlinear optical materials.