Modulation of the effective π-conjugation in anthracenyl chalcone for enhanced nonlinear optical properties and optical limiting potential

Abstract

The modulation of effective π-conjugation in anthracenyl chalcone derivatives is investigated to enhance their nonlinear optical (NLO) properties and optical limiting potential. Two derivatives, (E)-1,3-di(anthracen-9-yl)prop-2-en-1-one (1) and (E)-1-(anthracen-9-yl)-3-(naphthalen-2-yl)prop-2-en-1-one (2), are synthesized and characterized using Fourier Transform Infrared-Attenuated Total Reflectance (FTIR-ATR) spectroscopy, Nuclear Magnetic Resonance (¹H and ¹³C NMR), and UV–Visible spectroscopy. The absorption spectra reveal strong absorption in the 383–390 nm range, indicative of enhanced electron-accepting capabilities. Density Functional Theory (DFT) and Time-Dependent DFT (TD-DFT) calculations, employing the CAM-B3LYP/6–311 +  + G(d,p) approach, provide insights into the molecular electronic properties, including Frontier Molecular Orbitals (FMOs), Global Reactivity Descriptors (GRD), and hyperpolarizabilities. Natural Bond Orbital (NBO) analysis confirms significant intramolecular charge transfer, supporting the compounds’ potential for NLO applications. Notably, compound 1 exhibits a stronger third-order NLO response (χ³ = 3.99 × 10^-6 esu) compared to compound 2 (5.52 × 10^-6su), attributed to its extended conjugation and favorable electronic structure. These findings establish a strong correlation between π-conjugation modulation and enhanced NLO performance, positioning anthracenyl chalcones as promising candidates for advanced optical limiting applications.

Graphical Abstract