Multifunctional properties of benzophenone based acid dyes: Synthesis, spectral properties and computational study

The two series of benzophenone based acid dyes are synthesized using diazotized derivatives of amino benzene sulfonic acid and amino benzoic acid, which were characterized by H-1 NMR, C-13 NMR, CHN analysis and FTIR. They are applied on wool and silk substrate, and their functional properties such as UPF, antibacterial activity and fastness properties are evaluated. The 2,4-dihydroxy benzophenone series showed red shifted absorption and emission compared to 2-hydroxy-4-methoxy benzophenone series. The dyes show excellent UV protection on wool (UPF<40). The dyes and dyed fabrics shows acceptable antibacterial activities for Gram (+) Staphylococcus Aureus (ATCC 6538), Bacillus Subtilis (ATCC 6633) and Gram (-) Klebsiella Pneumonia (ATCC 4352), Salmonella Typhi (ATCC 6539) bacteria. All the fabrics dyed using synthesized dyes can be explored for functional clothing. Frontier Molecular Orbital diagrams obtained and HOMO-LUMO energy band gap was selected to calculate the electrophilicity index values of dyes using Density Functional Theory (DFT).