Computational and Spectroscopic Study of Newly Synthesized Bio‐Active Azo Dyes: DFT, Solvatochromism, and Preferential Solvation

Abstract

The computational, solvatochromism, and preferential solvation studies have been carried out on newly synthesized bio‐active azo dye molecules, namely 5‐[(E)‐(1,5‐dimethyl‐3‐oxo‐2‐phenyl‐2,3‐dihydro‐1H‐pyrazol‐4‐yl)diazenyl]‐6‐hydroxy‐4‐methyl‐2‐oxo‐1,2‐dihydropyridine‐3‐carbonitrile (A1) and 5‐[(E)‐(1,5‐dimethyl‐3‐oxo‐2‐phenyl‐2,3‐dihydro‐1H‐pyrazol‐4‐yl)diazenyl]‐6‐hydroxy‐1,4‐dimethyl‐2‐oxo‐1,2‐dihydropyridine‐3‐carbonitrile (A2). The electronic properties, chemical reactivity, and optical characteristics of the dye molecules have been computed using density functional theory (DFT). These findings suggest that the dye molecules are chemically active and show their suitability in NLO applications. The computations related to light‐harvesting properties have been carried out on the dye molecules. The ADME properties of the dye molecules have been evaluated using SwissADME and PreADMET online tools. The solvatochromic behavior of dye molecules has been investigated using Lippert's and Reichardt's solvent polarity parameters. The dye molecules' dielectric interactions and hydrogen bonding characteristics are analyzed using the Catalan multiple regression approach. The findings of the solvatochromic studies suggest the potentiality of the molecules in polarity sensing applications. Additionally, the solvatochromic data has been exploited to determine the excited state dipole moments using various solvatochromic approaches. The HOMO‐LUMO energy values, absorption wavelengths, light‐harvesting properties, and excited state dipole moments of the synthesized dye molecules indicate their suitability in dye‐sensitized solar cell applications. The preferential solvation studies of dye molecules have been conducted in a DCM–DMSO solvent mixture.