Bisazo dye compounds based on aliphatic and aromatic diamine linking groups: Thermal behavior, chemical stability, electrochemical study, interaction with AgNPs and in vitro anti-pathogen activity

In this study, a family of bisazo dye molecules (BA1-BA5) has been investigated as versatile compounds. Influence of various linking groups in amine moiety on thermal stability and electrochemical behavior of the compounds was determined and discussed. BA1 and BA2 with aliphatic-based diamine moiety have been found to be more thermal stable than others. Besides, the chemical stability of BA1-BA5 was studied in boiling water, acid and base media. All compounds showed strong resistance toward boiling water. Moreover, BA3-BA5 containing aromatic diamine moiety were stable after treatment with 6 N HCl. This feature may make them suitable as dye media in optical recording devices. Ag nanoparticles reacted with various bisazo dye molecules in a green approach to produce AgNPs/BA1-BA5 hybrids. Ag content in each hybrid was determined using an atomic absorption spectrometer (AAS). Antimicrobial activity of bisazo compounds and their nano silver counterparts has been screened in vitro against various pathogens including Methicillin-resistant Staphylococcus aureus (MRSA), Enterococcus faecalis (E. faecalis), Salmonella typhi (S.typhi), Pseudomonas aeruginosa (P. aeruginosa), Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) and Aspergillus fungi. Contrary to the bisazo compounds, AgNPs/BA hybrids were effective on both Gram-positive and negative bacteria. Moreover, AgNPs/BA3 and AgNPs/BA5 were able to efficaciously inhibit the growth of Aspergillus fungus.