Innovative Azo Disperse Dyes Containing a Hydrazide–Hydrazone Moiety: Design, DFT Calculations, Antimicrobial and Antibiofilm Activities, and Dyeing Performance on Polyester Fabrics

This study presents a novel azo disperse dye that incorporates a hydrazide-hydrazone moiety, designed for multifunctional applications. Three novel azo dyes were synthesized by treating resorcinol <b>3</b> with diazotized 4-aminobenzophenone <b>1</b>, followed by the condensation of the benzophenone derivative <b>4</b> with acid hydrazide. The molecular structures of newly synthesized azo dye molecules have been understood through the utilization of spectroscopic and elemental analysis techniques. The main goal of the study was to optimize dyeing factors, such as temperature, duration, pH, and shade, to understand how disperse dyes such as benzophenone-based disperse dye (compound <b>4</b>) and hydrazone derivatives (compounds <b>8</b> and <b>12</b>) affect polyester fabrics. The colored polyester samples exhibited a range of colors from beige, reddish brown, to dark brown, depending on the coupler moieties at a concentration of 3%. Overall, synthetic dyes seem to be advantageous options for dyeing polyester materials in various hues. The antibacterial and antifungal properties of compounds <b>4</b>, <b>8</b>, and <b>12</b> were evaluated against various pathogens. Benzophenone <b>4</b> demonstrated the strongest antifungal activity against <i>Aspergillus fumigatus</i> and <i>Candida albicans</i>, while <b>8</b> and <b>12</b> were more effective against Gram-positive bacteria but less so against Gram-negative bacteria. Hydrazone <b>12</b> exhibited the lowest MIC and MBC values for <i>Bacillus subtilis</i>. Biofilm assays revealed that compounds <b>4</b> and <b>8</b> significantly inhibited biofilm formation in <i>Staphylococcus aureus</i>. Additionally, molecular structures were analyzed using DFT, and docking experiments predicted interactions with <i>S. aureus</i> DNA gyrase B and CTX-M β-lactamases, highlighting their potential for further antibacterial applications.